Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.cej.2023.144544

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

Abstract

Reactions occurring at surfaces and interfaces necessitate the creation of well‐designed surface and interfacial structures. To achieve a combination of bulk material (i.e., framework) and void spaces, a meticulous process of “nano‐architecting” of the available space is necessary. Conventional porous materials such as mesoporous silica, zeolites, and metal–organic frameworks lack advanced cooperative functionalities owing to their largely monotonous pore geometries and limited conductivities. To overcome these limitations and develop functional structures with surface‐specific functions, the novel materials space‐tectonics methodology has been proposed for future materials synthesis. This review summarizes recent examples of materials synthesis based on designing building blocks (i.e., tectons) and their hybridization, along with practical guidelines for implementing materials syntheses and state‐of‐the‐art examples of practical applications. Lastly, the potential integration of materials space‐tectonics with emerging technologies, such as materials informatics, is discussed.

DOI： 10.1002/anie.202307615

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

Abstract

Ammonia borane (AB) is a promising material for chemical H₂ storage owing to its high H₂ density (up to 19.6 wt %). However, the development of an efficient catalyst for driving H₂ evolution through AB hydrolysis remains challenging. Therefore, a visible‐light‐driven strategy for generating H₂ through AB hydrolysis was implemented in this study using Ni−Pt nanoparticles supported on phosphorus‐doped TiO₂ (Ni‐Pt/P‐TiO₂) as photocatalysts. Through surface engineering, P‐TiO₂ was prepared by phytic‐acid‐assisted phosphorization and then employed as an ideal support for immobilizing Ni−Pt nanoparticles via a facile co‐reduction strategy. Under visible‐light irradiation at 283 K, Ni₄₀Pt₆₀/P‐TiO₂ exhibited improved recyclability and a high turnover frequency of 967.8 mol mol_Pt⁻¹ min⁻¹. Characterization experiments and density functional theory calculations indicated that the enhanced performance of Ni₄₀Pt₆₀/P‐TiO₂ originated from a combination of the Ni−Pt alloying effect, the Mott–Schottky junction at the metal‐semiconductor interface, and strong metal‐support interactions. These findings not only underscore the benefits of utilizing multipronged effects to construct highly active AB‐hydrolyzing catalysts, but also pave a path toward designing high‐performance catalysts by surface engineering to modulate the electronic metal‐support interactions for other visible‐light‐induced reactions.

DOI： 10.1002/anie.202305371

Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

DOI： 10.1021/acsnano.3c01758

Publishing type：Research paper (scientific journal)   Publisher：Wiley  

DOI： 10.1002/chem.202300218

Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

DOI： 10.1007/s12613-022-2573-6

Other Link： https://link.springer.com/article/10.1007/s12613-022-2573-6/fulltext.html

Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry (RSC)  

Metal–organic framework (MOF) derivatives, such as pyrolytic carbons, pyrolytic metal-containing carbons, and MOF-based hybrids, have been designed to replace conventionally used carbon materials for promoting capacitive deionization performance.

DOI： 10.1039/d2ee03530h

Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry (RSC)  

Fibrous hydroxyapatite was synthesised from α-tricalcium phosphate in ethanol and acetic acid solutions via a water controlled-release solvothermal process (WCRSP). Rice-like particles of β-tricalcium phosphate were formed by adjusting the...

DOI： 10.1039/d2ce01703b

Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

DOI： 10.1021/acs.langmuir.2c02872

Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

DOI： 10.1021/acs.inorgchem.2c03550

Publishing type：Research paper (scientific journal)   Publisher：MDPI AG  

Ternary metal oxides (TMOs) with flexible band structures are of significant potential in the field of photocatalysis. The efficient utilization of renewable and green solar energy is of great importance to developing photocatalysts. To date, a wide range of TMOs systems has been developed as photocatalysts for water and air purification, but their practical applications in visible light-assisted chemical reactions are hindered mainly by its poor visible light absorption capacity. Introduction of N atoms into TMOs can narrow the band-gap energy to a lower value, enhance the absorption of visible light and suppress the recombination rate of photogenerated electrons and holes, thus improving the photocatalytic performance. This review summarizes the recent research on N-modified TMOs, including the influence of N doping amounts, N doping sites, and N-induced phase transformation. The introduced N greatly tuned the optical properties, electronic structure, and photocatalytic activity of the TMOs. The optimal N concentration and the influence of N doping sites are investigated. The substitutional N and interstitial N contributed differently to the band gap and electron transport. The introduced N can tune the vacancies in TMOs due to the charge compensation, which is vital for inducing different activity and selectivity. The topochemical ammonolysis process can convert TMOs to oxynitride with visible light absorption. By altering the band structures, these oxynitride materials showed enhanced photocatalytic activity. This review provides an overview of recent advances in N-doped TMOs and oxynitrides derived from TMOs as photocatalysts for environmental applications, as well as some relevant pointers for future burgeoning research development.

DOI： 10.3390/catal12121568

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.jece.2022.108169

Publishing type：Research paper (scientific journal)   Publisher：The Society of Powder Technology, Japan  

DOI： 10.4164/sptj.59.338

Language：English   Publishing type：Research paper (scientific journal)   Publisher：World Scientific Pub Co Pte Ltd  

The bismuth vanadate (BiVO₄) photocatalyst was successfully synthesized by an organic-aqueous hetero-phase reaction method using organic additives (oleic acid, oleyl alcohol, and oleylamine) to investigate the reaction mechanism. The BiVO₄ with a star-like morphology could be synthesized with oleylamine. Bismuth precursors formed by the interaction between bismuth and the amino group of oleylamine were nano-sized complex particles with amorphous phase, finally resulted in the formation of star-like morphology. Moreover, BiVO₄ synthesized with oleylamine showed excellent photocatalytic activity on degradation of rhodamine B.

DOI： 10.1142/s1793604722500205

Scopus

Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

B and N co-doped anatase, rutile, and brookite TiO2 (abbreviated as BN-Ana, BN-Rut, and BN-Bro) were successfully synthesized. The apparent color of as-obtain BN-Ana, BN-Rut and BN-Bro was red, cyan and yellow-green, respectively. The mechanisms of various coloring were concluded as the different band gap configurations and the formation of covalent B-N bonding. The nitridation time expressed less effect on changing the color. On the contrary, nitridation temperature enabled the distinct color changes by altering the brightness. Lower temperature, fewer doping concentration, and brighter apparent color, vice versa. Through tuning the brightness, a gradient of yellow-orange-red was achieved in the case of BN-Ana, as well the transitions of grey-to-cyan and white-to-pale-yellow were achieved in BN-Rut and BN-Bro, respectively. This research proposed a method for the synthesis of color-full titania pigment without the addition of other toxic transition metal elements.

DOI： 10.1016/j.apt.2022.103576

Scopus

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

DOI： 10.1002/asia.202200143

Other Link： https://onlinelibrary.wiley.com/doi/full-xml/10.1002/asia.202200143

Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

The present study explores the oxygen storage capacity of YBaCo4O7+δ prepared by a glycine-complex decomposition method. We reported for the first time that the YBaCo4O7+δ sample was successfully synthesized at such a low temperature of 800 °C by this method. The YBCO-800 N sample exhibited a faster oxygen absorption/desorption speed than that of high calcination temperature samples, and the time required for complete oxygen storage/release was 5 and 6 min at 360 °C, respectively. Moreover, the superior performance observed for this product in the temperature swing adsorption process makes it a promising candidate in oxygen production technologies. This research demonstrated that the glycine-complex decomposition method is an effective method for improving the oxygen storage property of YBaCo4O7+δ and provides a new insight into designing other novel oxygen storage materials.

DOI： 10.1021/acsami.1c15419

Scopus

PubMed

Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

In this work, two-dimensional crystalline C3N4 (CCN) was obtained by promoting the self-condensation reaction of dicyandiamide in an air atmosphere via the molten salt method. Studies show that compared with polymer-C3N4 (PCN) ((9.8 m2/g)), CCN has a larger specific surface area (77.1 m2/g)) and better crystallinity. Additionally, the resistance of CCN in the air is 40 MΩ, 1250 times lower than that of polymer-C3N4 (PCN) (∼50000 MΩ). Secondly, when 50 ppm toluene gas analysis flows into the CCN based gas sensor at room temperature, the gas response value is 350. The CCN based gas sensor works for 60 days, or after 25 cycles continuously, the gas response value remains at about 350 (Rg/Ra), which is due to the excellent crystallinity, optimized π conjugate system, and enhanced interlayer van der Waals of CCN. Additionally, the critical effect of crystallinity on the gas sensitivity of carbon nitride is also discussed in detail.

DOI： 10.1016/j.apt.2021.09.027

Scopus

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.cej.2021.130220

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.seppur.2021.118815

Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

Molybdenum sulfide selenide (MoS2-xSex) solid solution nanoparticles were investigated to modify the crystal structure of molybdenum disulfide (MoS2) for improving the nitric oxide (NO) detection performance at room temperature. The hydrothermal reaction followed by post-annealing treatments was used to engineer the structural, morphological, and electronic properties of MoS2-xSexnanoparticles. MoS2-xSexsamples with different selenium addition ratios (x= 0, 0.2, 1, 1.8, and 2) were prepared to understand the optimum condition for NO detection. The gradual addition of the selenium atom expanded the interlayer distance and increased the lattice parametera=bfrom 3.148(0.1) Å forx= 0 to 3.279(0.08) Å forx= 2. The chemical bonding of Mo-S expands, while Mo-Se bonding compresses in MoS2-xSexsolid solution. The particle size also decreased after selenium addition from 500 nm forx= 0 to 80 nm forx= 2. The band gap also gradually decreased after selenium addition from 1.66 to 1.44 eV, which is related to an increase in the conductivity. The NO detection performance of MoS2-xSexwithx= 1 showed the highest NO detection performance with a response value of around 48% due to its small particle size, high adsorption energy, high charge transferability, and good stability. MoS2-xSexwithx= 1 detection performance was relatively stable under different humidity conditions and also was very sensitive to the NO gas molecule compared to volatile organic compound gases as well as hydrogen gas. This indicates that thex= 1 nanoparticle is very promising to be applied as a NO detection device at room temperature.

DOI： 10.1021/acsanm.1c00926

Scopus

Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

Lanthanide-substituted YMnO3+δ nanoparticles with the hexagonal phase, denoted as R0.25Y0.75MnO3+δ (R = Er, Dy, Tb, Gd, and Sm), have been successfully synthesized by the polymerized complex method. The substitutions did not largely affect the morphologies and specific surface area of the obtained R0.25Y0.75MnO3+δ nanoparticles. From the evaluation for the oxygen storage/release properties, the oxygen storage capacity (OSC) increased significantly by the Tb substitution, and the oxygen absorption/release rate strongly depended on the ion size of the substituted lanthanides. It was found that Tb4+ existed in Tb0.25Y0.75MnO3+δ after oxygen absorption, demonstrating that the remarkable increase in the OSC of the Tb-substituted sample was due to the oxidation of not only Mn3+ to Mn4+ but also Tb3+ to Tb4+. In addition, the unit cell volume increasing with the R ion size, which can lead to the promotion of the oxygen diffusion in the crystal structure, was the factor leading to the increase of the oxygen absorption rate. Especially, Sm0.25Y0.75MnO3+δ showed an excellent OSC of 3 + δ= 3.34 (the weight increase rate was 2.64 wt %) even under a rapid temperature swing rate of 20 °C/min.

DOI： 10.1021/acsami.1c06880

Scopus

PubMed

Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Hindawi Limited  

A unique structural transformation of a lepidocrocite-type layered titanate, K0.8Ti1.73Li0.27O4, into a rutile-type TiO2 has recently been realized via dilute HCl treatment and subsequent drying at room temperature for producing rutile-nanoparticle-decorated protonated layered titanate exhibiting highly efficient photocatalytic activity. Herein, the authors report synthesis of a lepidocrocite-type layered cesium titanate with nominal compositions of <inline-formula>
<math xmlns="http://www.w3.org/1998/Math/MathML" id="M2">
<mtext>C</mtext>
<msub>
<mrow>
<mtext>s</mtext>
</mrow>
<mrow>
<mn>0.7</mn>
</mrow>
</msub>
<mtext>T</mtext>
<msub>
<mrow>
<mtext>i</mtext>
</mrow>
<mrow>
<mn>1.825</mn>
<mo>‐</mo>
<mi>x</mi>
<mo>/</mo>
<mn>2</mn>
</mrow>
</msub>
<mtext>N</mtext>
<msub>
<mrow>
<mtext>i</mtext>
</mrow>
<mrow>
<mi>x</mi>
</mrow>
</msub>
<mo>□</mo>
<msub>
<mrow />
<mrow>
<mn>0.175</mn>
<mo>‐</mo>
<mi>x</mi>
<mo>/</mo>
<mn>2</mn>
</mrow>
</msub>
<msub>
<mrow>
<mtext>O</mtext>
</mrow>
<mrow>
<mn>4</mn>
</mrow>
</msub>
</math>
</inline-formula> (<inline-formula>
<math xmlns="http://www.w3.org/1998/Math/MathML" id="M3">
<mi>x</mi>
<mo>=</mo>
<mn>0</mn>
</math>
</inline-formula>, 0.05, 0.1, and 0.35) through solid-state reactions of Cs2CO3, TiO2, and Ni(CH3COO)2·4H2O at different temperatures (600 or 800°C), followed by treatment with dilute HCl and subsequent drying to produce a Ni-doped protonated layered titanate/TiO2 composite. <inline-formula>
<math xmlns="http://www.w3.org/1998/Math/MathML" id="M4">
<mtext>C</mtext>
<msub>
<mrow>
<mtext>s</mtext>
</mrow>
<mrow>
<mn>0.7</mn>
</mrow>
</msub>
<mtext>T</mtext>
<msub>
<mrow>
<mtext>i</mtext>
</mrow>
<mrow>
<mn>1.825</mn>
<mo>‐</mo>
<mi>x</mi>
<mo>/</mo>
<mn>2</mn>
</mrow>
</msub>
<mtext>N</mtext>
<msub>
<mrow>
<mtext>i</mtext>
</mrow>
<mrow>
<mi>x</mi>
</mrow>
</msub>
<mo>□</mo>
<msub>
<mrow />
<mrow>
<mn>0.175</mn>
<mo>‐</mo>
<mi>x</mi>
<mo>/</mo>
<mn>2</mn>
</mrow>
</msub>
<msub>
<mrow>
<mtext>O</mtext>
</mrow>
<mrow>
<mn>4</mn>
</mrow>
</msub>
</math>
</inline-formula> with an optimized Ni content obtained at a lower temperature was converted into a Ni-doped protonated layered titanate/TiO2 composite to exhibit high photocatalytic activity for NO<inline-formula>
<math xmlns="http://www.w3.org/1998/Math/MathML" id="M5">
<msub>
<mrow />
<mrow>
<mi>x</mi>
</mrow>
</msub>
</math>
</inline-formula> decomposition reactions.

DOI： 10.1155/2021/8847956

Other Link： http://downloads.hindawi.com/journals/ijp/2021/8847956.xml

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.jcat.2020.11.025

Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry (RSC)  

This study proposed a new layer modification technique, “layer charge control”, for layered perovskites, and the structures of the obtained charge neutral [CeTa₂O₇] perovskite sheet were characterized theoretically and experimentally.

DOI： 10.1039/d1sc03053a

Scopus

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.jmst.2020.06.043

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.jmst.2020.07.040

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Ceramic Society of Japan  

© 2020 The Ceramic Society of Japan. All rights reserved. Attention has recently been paid to oxyfluorides, one of the mixed anion materials, because they possess unique properties for many kinds of application fields. Because the general synthesis processes for oxyfluorides are based on troublesome methods, novel safe and facile processes are required. In this study, MoO3 was solvothermally reacted with KF, RbF, and CsF at 200 °C to form potassium, rubidium, and cesium molybdenum oxyfluorides. The reaction of MoO3 with KF and RbF led to the formation of K3MoO3F3 and Rb3MoO3F3 with a known structure, respectively, while the reaction of MoO3 with CsF induced an unknown phase which should be Cs3MoO3F3 with the similar structure to those of K3MoO3F3 and Rb3MoO3F3. A3MoO3F3 (A = K, Rb, and Cs) has not been synthesized under liquid phase until now, and this research clarified this kind of the solvothermal reaction can lead to the formation of unique oxyfluorides at low temperature. In addition, Cs3MoO3F3 was converted into Cs3Mo2O6F3 by treatment with methanol, suggesting the instability of Cs3MoO3F3. This kind of conversion reaction from one oxyfluoride to the other oxyfluoride has not been reported, and the development of such chemical conversion may lead to the formation of new oxyfluorides.

DOI： 10.2109/jcersj2.20182

Scopus

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

NaMoO3F and Na5W3O9F5 were synthesized by solvothermal reaction of MoO3 and WO3, respectively, with NaF in nonaqueous solvents. These reactions were realized at low temperatures (150-200 °C) without the use of HF. This synthesis method is much more facile and safe procedure compared with general synthesis methods for oxyfluorides which includes hydrothermal reaction under a presence of HF or solid-state reaction at high temperatures in vacuum sealed tube or under high pressure. In the case of the reaction of MoO3 with NaF, the kind of solvent largely affected the obtained morphologies of NaMoO3F. The morphology in the case of acetonitrile as a solvent was rodlike with a micrometer-scale size, while that in the case of ethanol was polyhedral with a size of several hundred nanometers. In addition, the solvothermal reaction of WO3 with NaF led to the formation of Na5W3O9F5. Also, the difference of solvents for the solvothermal reaction affected the obtained particle sizes. The effect of the solvents on the morphologies of the obtained oxyfluorides probably resulted from the difference of the solubility of NaF and the subsequent dissolution ratio of MoO3 or WO3 in the used solvents. Our synthesis method can expand the applicability of oxyfluorides by providing a new phase and/or unique morphology.

DOI： 10.1021/acs.inorgchem.0c01175

PubMed

Publishing type：Research paper (scientific journal)  

Molybdenum sulfide (MoS2) was engineered by intercalation of ethylene glycol to form 2H (semiconductor) and 1T (metallic) phases. MoS2 was successfully synthesized under solvothermal conditions with different solvents. Water, ethylene glycol (EG), and a mixture of water and EG were used as the solvent. The obtained samples were denoted as MoS2 (W), MoS2 (EG), and MoS2 (EG:W), respectively. The use of ethylene glycol as a solvent expands the (0 0 2) lattice spacing which indicated the expansion of interlayer spacing by intercalation of EG through solvothermal reaction. The MoS2 intercalated with EG possessed higher 1T phase compared to MoS2 without any intercalation. The obtained MoS2 was applied for room temperature toluene sensing with different relative humidity (RH, 20, 40, 60, 80%). The increase of relative humidity could continuously increase the base resistance and also the sensing response of MoS2 (W) and MoS2 (EG:W). For MoS2 (EG), 60% relative humidity showed the optimum condition for sensing applications. The all MoS2 (W), MoS2 (EG), and MoS2 (EG:W) had good sensing performance at 60% RH with sensing ability (ΔR/Rair%) in 100 ppm toluene around 12.50, 14.53, 16.29%, respectively. 1T-MoS2 is taking a major contribution on the sensing properties of MoS2.

DOI： 10.1016/j.apt.2020.02.022

Scopus

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER  

Oxynitrides with narrow band gap are promising materials as visible-light sensitive photocatalysts, because introduction of nitrogen ions can negatively shift the position of valence band maximum of the corresponding oxides to negative side. (Zn1+xGe)(N2Ox) with wurtzite structure is one of the oxynitride materials. (Zn1+xGe)(N2Ox) with nanotube morphology was synthesized by nitridation of Zn2GeO4 nanorods at 800 degrees C for 6 h. During the nitridation process, the nanorod with smooth surface was transformed into nanotube with rough surface in spite of no template for formation of tube structure. The nanotube formation can be caused by ordered morphological transformation from Zn2GeO4 nanorod during the nitridation. (Zn1+xGe)(N2Ox) nanotube exhibited a large specific surface area due to its nanotube morphology and the ability to be responsive to visible light because of the narrow band gap of 2.76 eV. Compared to (Zn1+xGe)(N2Ox) synthesized by conventional solid state reaction, the optimized (Zn1+xGe)(N2Ox) nanotube possessed enhanced photocatalytic NO, decomposition activity under both ultraviolet and visible light irradiation.

DOI： 10.1016/j.jhazmat.2020.122709

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

DOI： 10.1007/s12613-020-2143-8

Other Link： http://link.springer.com/article/10.1007/s12613-020-2143-8/fulltext.html

Publishing type：Research paper (scientific journal)  

YMnO3 nanoparticles with a diameter of ca. 100 nm, which were synthesized by the polymerized complex method, exhibited a high O2 storage/release rate, because nanoparticle morphology increased the O2 accessible surface area of the material. This material with a high O2 storage/release rate is promising as a separator of O2 from air.

DOI： 10.1039/c9dt04095a

Scopus

PubMed

Authorship：Lead author,　Corresponding author   Language：English  

Language：English   Publishing type：Research paper (scientific journal)  

The bulk graphitic carbon nitride (CN) suffers from low specific surface area, which limits its practical application for air purification. Here, we reported a facile post-thermal treatment to break bulk CN into nanosheets whose specific surface areas increased from 13.6 m2 g-1 to 68.0 m2 g-1. The yield of CN nanosheets reached up to 67%, and its photocatalytic decomposition of NOx activity was about 3.0 times higher than that of bulk CN. Moreover, the CN nanosheets obtained at 550 °C with higher specific surface area (113.9 m2 g-1) displayed lower photocatalytic activity than that obtained at 500 °C with lower specific surface area (68.0 m2 g-1), which was attributed to its lower valence band. This study illustrates that many factors including specific surface area and band structure could affect the performance of photocatalysts so that it is necessary to take account of various factors. Moreover, the facile and high yield thermal treatment provides the foundation for further large-scale industrial applications.

DOI： 10.1088/1361-6528/ab59f6

Scopus

PubMed

Language：English   Publishing type：Research paper (scientific journal)  

Toluene is one of the harmful volatile organic compounds (VOCs) for both human health and environments. Thus, to prevent the hazardous effect of toluene, fast detection at an early stage is needed. CuO shows the merit for a wide range responsivity to VOCs but suffers from small response value, slow response/recovery speeds, and low durability. Herein, we report a facile preparation of CuO/Ti3C2Tx MXene hybrids via electrostatic self-assembly. The CuO nanoparticles (∼7 nm) were uniformly dispersed on the surface and the interlayers of the Ti3C2Tx MXene, forming hybrid heterostructures. The CuO/Ti3C2Tx MXene exhibited the improved toluene gas sensing response (Rg/Ra) of 11.4, which is nearly 5 times higher than that of the pristine CuO nanoparticles (2.3) to 50 ppm of toluene at 250 °C. Due to the different work function (φ), the Schottky junction was established at the interface of CuO/Ti3C2Tx MXene, acting as a hole trapping region (HTR) at the Ti3C2Tx MXene side. Compared to other hybrid 2D materials such as MoS2 and rGO, which possess a higher work function, the CuO/Ti3C2Tx MXene maintained better toluene sensing performance. Thus, the work function is critical for designing a high sensing performance of hybrid metal oxides/2D materials. The hybridization of CuO with Ti3C2Tx MXene improved not only enhancement of the response time but also the selectivity and the responses (270 s) and recovery times (10 s) compared with those of CuO, due to high conductivity of the metallic phase in Ti3C2Tx MXene. Such excellent performance showed the promising applications of metal oxides/2D hybrid materials for VOCs gas sensing.

DOI： 10.1021/acsanm.0c00749

Scopus

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.apcatb.2020.119376

Language：English   Publishing type：Research paper (scientific journal)  

Graphitic carbon nitride / reduced graphene oxide (g-C3N4/rGO) nanocomposites have become research hotspots owing to its excellent charge carrier separation efficiency and enhanced photocatalytic activity. Herein, we developed a facile alkali-assisted hydrothermal strategy to prepare g-C3N4/rGO nanocomposites. In the hydrothermal process, the NaOH not only played an important role in etching the bulk g-C3N4 into nanosheets to increase its specific surface area and active sites, but also promoted the reduction of GO to enhance the conductivity of rGO. The rGO sheets could act as an excellent electron acceptor and electronic conductive channels to improve the separation efficiency of photogenerated electron-hole pairs. The resultant g-C3N4/rGO nanocomposites exhibited 2.7 times higher photocatalytic NOx removal activity than that of bulk g-C3N4 due to the enlarged specific surface area and the enhanced separation efficiency of photogenerated carriers. Moreover, the obtained metal-free photocatalyst displayed outstanding photocatalytic performance under visible light irradiation (λ˃400 nm), compared with previously reported traditional-metal-based semiconductor photocatalysts. This work may provide new insights into preparing g-C3N4/rGO nanocomposites with enhanced photocatalytic activity.

DOI： 10.1016/j.apsusc.2020.146213

Scopus

Language：English   Publishing type：Research paper (scientific journal)  

IF=3.25

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE SA  

In order to realize high efficiency photocatalysis deNO(x) effect, a homogeneous three-component photocatalyst, C3N4/rGO/C-TiO2 was successfully synthesized by an in situ synthesis method. First, C3N4/rGO composite was prepared to increase the contact surface between them. Then, C-TiO2 was crystallized on the surface of the C3N4/rGO to obtain relatively dispersed C-TiO2 nanoparticles on the C3N4/rGO. The as-prepared photocatalyst was evaluated by NO removal ratio under weak visible and UV LED light irradiation. C3N4/rGO/C-TiO2 was compared with sample prepared by simple mixing of C3N4, rGO and C-TiO2 within a solution. As a result, sample prepared by in situ synthesis exhibited the highest photocatalytic activity, together with high apparent quantum efficiency. The transient absorption measurement clarified that the composite photocatalyst possessed longer carrier lifetime if compared to that of each component material, resulted to its higher photocatalytic activity. The three-component photocatalyst is thought to have shown enhancement in photocatalytic activity by Z-scheme mechanism with rGO as an electron mediator to improve the performance of Z-scheme.

DOI： 10.1016/j.cej.2020.124616

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry (RSC)  

<p>NiO with polar (111) facets was successfully synthesized from the transformation of a layered NiOHCl, exhibiting excellent NO_x detection and degradation activity.</p>

DOI： 10.1039/d0qi00682c

Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

DOI： 10.1021/acsanm.0c01352

Language：English   Publishing type：Research paper (scientific journal)  

The monoclinic phase of VO2 has promising application as a smart window material because it possesses a reversible metal-to-semiconductor transformation with a critical temperature of 68 °C. The high critical temperature must be lowered to achieve a possible application. Anion doping has been widely researched as possible doping of VO2(M) with fluorine is the main option nowadays. However, other halogen elements such as chlorine have not been investigated albeit possessing possible advantages properties. In this work, we report the use of chlorine anion as doping for VO2(M) to lower its critical temperature and to enhance its thermochromic performance. The synthesis was performed using a facile one-step hydrothermal reduction of vanadium pentoxide by hydrazine at 350-490 °C, using ammonium chloride as the source of the anion. The result showed that the optimum temperature to synthesize Cl-doped VO2(M) was 490 °C. The lowest critical temperature that can be achieved by chlorine-doped VO2(M) was at 59.9 °C. The thermochromic performance of Cl-doped VO2(M) was improved compared to pristine VO2(M) nanoparticle. This finding provides a novel use of chlorine-doped VO2(M) with a facile one-step hydrothermal method to synthesize chlorine-doped VO2(M) as well as the feasibility of chlorine-doped VO2(M) as a smart window material.

DOI： 10.1142/S1793604719510081

Scopus

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Microspherical particles of Rh-doped SrTiO3 (SrTiO3:Rh) having size of 1-2 mu m were synthesized by a spray drying (SD) method employing a water-soluble ammonium trilactatotitanate. When the calcination temperature increased up to 1200 degrees C, primary particles grew significantly while the microspherical morphology of the secondary particles was kept. Dynamic light scattering analysis proved well-dispersive nature of the SD sample. Photocatalytic activities of SrTiO3:Rh synthesized by the SD method, solid state reaction (SSR), and a poly-merizable complex (PC) method were evaluated for H-2 evolution using an electron donor such as methanol, Fe2+, or [Co(bPY)(3)](2+) and Z-scheme water splitting combined with BiVO4 of an O-2-evolving photocatalyst and either Fe3+/2+, [Co(bpy)(3)](3+/2+), or reduced graphene oxide as an electron mediator. SrTiO3:Rh prepared by the SD method showed much higher activities for all Z-scheme water splitting than the samples synthesized by the SSR method. Activities of the SD sample for Z-scheme water splitting using electron shuttles, Fe3+/2+ and [Co(bpy)(3)](3+/2+), were slightly higher or comparable to those of the PC sample whereas the SD sample achieved higher activity in Z-scheme water splitting based on interparticle electron transfer. In addition, even when the mass of SrTiO3:Rh used for the Z-scheme system with Fe3+/2+ was decreased from 50 mg to 30 mg, the SD sample still showed high activity while the activity decreased for the SSR and PC samples. Thus, usefulness of the SD method to obtain highly active SrTiO3:Rh with well-dispersive nature has been demonstrated.

DOI： 10.1016/j.apcatb.2019.04.009

Web of Science

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

Publishing type：Research paper (scientific journal)  

A facile solvothermal synthesis in an ethanol/acetic acid mixture for the fabrication of SnO2 with a controllable hierarchical spherical size and micro-/mesoporosity is presented. SEM, TEM and N2 adsorption/desorption investigation unveiled that the obtained SnO2 spheres exhibited a particle size in the range of 0.6–1.6 μm and a pore size of about 1.4–1.9 nm depending on the volume ratio of acetic acid to ethanol in the reaction mixture, and the spheres were constructed by nanoscale particles. Due to its micro-/mesoporous structure, the SnO2 spheres exhibited large specific surface areas over 100 m2/g. When 10 vol. % of acetic acid at 200 °C for 20 h was used for the reaction, the obtained SnO2 possessed a higher specific surface area of 145 m2/g (SnO2_10). The gas sensing property of SnO2_10 without an additional noble metal co-catalyst exhibited a large toluene sensing response (Ra/Rg) of 20.2 at 400 °C, which was about 6 times higher and acceptable selectivity compared to those of other samples. The study found that the sensing performance in the SnO2 hierarchical spheres was influenced by several factors e.g. particle morphology, pore size and specific surface area rather than only a single parameter. Therefore, a precise control of those influencing parameters may lead to the optimum sensing property. These findings are important for the further development of the micro-/mesoporous metal-based oxide as an alternative successor for toluene gas sensor material.

DOI： 10.1016/j.ceramint.2019.05.043

Scopus

Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

GaN:ZnO solid solution nanoparticles and films were synthesized by using ZnGa2O4 nanoparticles with a particle size of below 25 nm obtained hydrothermally as a precursor. Nitridation of powder ZnGa2O4 nanoparticles led to the formation of GaN:ZnO nanoparticles. The nitrided samples have higher specific surface area than those obtained by conventional method, which induces higher photocatalytic NOx decomposition activity. In addition, a transparent coating film with ZnGa2O4 nanoparticles was converted to GaN:ZnO film after nitridation. The nitrided film absorbs UV and blue light and is transparent for light of wavelength over 500 nm (the transmittance is over 90 %). This means that the nitridation does not lead to the formation of scattering domains by the large-size particles and cracks. This method for film preparation is much cheaper than conventional CVD and sputtering processes. These results strongly suggest the utility of ZnGa2O4 nanoparticles not only for the formation of GaN:ZnO solid solution nanoparticles with high specific surface area but also for the preparation of transparent GaN:ZnO solid solution films.

DOI： 10.1002/ejic.201900045

Web of Science

Language：English   Publishing type：Research paper (scientific journal)  

The water-controlled release process (WCRP) was utilized for the synthesis of TiO2 photocatalyst. The effect of alkylated esterified WCRP system on the morphology, specific surface area (SSA) and photocatalytic activity of TiO2 were studied systematically. By changing the structure of alcohol and acid involved in the esterification reaction, we found that the SSA and photocatalytic activity of TiO2 obtained in an ethanol/acetic acid reaction mixture showed the best results. Interestingly, the TiO2 obtained in t-butanol/acetic acid contains both the anatase and rutile phase, while the other systems only possessed anatase phases. The conditions of ethanol and acetic acid esterification were optimized and the experimental results showed that the SSA of nano-TiO2 was improved by shorting the reaction time or adding an organic solvent, which can form an azeotrope with water, but no effect on the photocatalytic activity could be observed. The reaction mechanism of esterified WCRP system was furthermore studied by NMR spectroscopy, showing three kinds of reaction, namely esterification, etherification and hydrolysis.

DOI： 10.1088/2053-1591/ab0d67

Scopus

Language：English   Publishing type：Research paper (scientific journal)  

Publishing type：Research paper (scientific journal)  

Extremely stable gas sensors at elevated temperature (T > 400 °C) with rapid detection of hydrogen gas are urgently demanded especially for hydrogen production industry which typically involves a high-temperature system. Gallium nitride (GaN) possesses excellent physicochemical properties and is expected to be one candidate for high temperature gas sensor. In this work, the GaN preparation from α–GaOOH precursors by a direct nitridation method under NH3 flow is presented. The nitridation was done at various temperatures to obtain GaN with different oxygen contents, which played a vital role in gas sensing response of thick film GaN in various concentration of H2 gas at 500 °C. The sensitivity of the obtained GaN with 2.07 wt.% of oxygen content was 10 times higher than that sample with the lowest oxygen content (1.9 wt.%) and the sensitivity drastically decreased when the oxygen content was 2.53 wt.%. The sensors also demonstrated high stability as indicated by their repeatable feature after being exposed at a various concentration of H2 (150–750 ppm). Furthermore, the GaN showed higher sensitivity than that of β–Ga2O3 sensor.

DOI： 10.1016/j.snb.2018.08.021

Scopus

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Composite type photocatalyst F-TiO2/(N,C)-TiO2 consisted of anatase-type TiO2 with fluorine-doping (F-TiO2) and TiO2 with nitrogen and carbon-doping ((N,C)-TiO2) was prepared by simple physical mixing to exhibit higher visible-light responsive photocatalytic nitrogen oxide (NO) decomposition activity than those of F-TiO2 and (N,C)-TiO2. Transient absorption measurement clarified that the composite possessed longer carrier lifetime compared to that of each material (F-TiO2 or (N,C)-TiO2), resulting in higher photocatalytic activity. In the composite, photoexcited holes and electrons, which are not in impurity level but in valence and conduction band, respectively, should photocatalytically decompose NO, judging from the redox potential of O-2/O-2(center dot-) and the band positions of F-TiO2 and (N,C)-TiO2. The mechanism for higher visible-light photocatalytic activity, or longer carrier lifetime can be explained by charge transfer between F-TiO2 and (N,C)-TiO2 through their impurity levels. The charge transfer should make photoexcited carries spatially separated to enhance the photo catalytic activity.

DOI： 10.1016/j.apcatb.2018.07.038

Web of Science

Publishing type：Research paper (scientific journal)   Publisher：IOP Publishing  

DOI： 10.1088/1361-6528/aab752

Other Link： http://iopscience.iop.org/article/10.1088/1361-6528/aab752/pdf

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Institute of Physics Publishing  

Various types of coating films were obtained from hydrothermally synthesized Nb-doped TiO2 (NTO) and CsxWO3 (CWO) nanoparticles. The coating films possessed multifunctionality including near infrared (NIR) absorption and photocatalysis abilities. The NTO and CWO nanoparticles were synthesized by a unique solvothermal reaction in which water induced by an esterification reaction between alcohol and carboxylic acid can act as a hydrolyzing agent for metal precursors. NTO was synthesized by the unique solvothermal reaction for the first time. The reaction accompanied by the reduction of Ti4+ to Ti3+ led to the formation of nanoparticles with both NIR absorption and photocatalytic properties. The effect of the ethanol-acetic acid ratio on the morphology of the obtained NTO was investigated, and the larger amount of acetic acid led to a larger nanoparticle size, indicating the size controllability. The two types of coating film, including CWO and NTO nanoparticles, were obtained for comparison: (1) coexistent coating film: one side of the quartz glass was coated with a dispersion, including both CWO and NTO nanoparticles, and (2) double-sided coating film: a quartz glass coated with a CWO dispersion on one side and an NTO dispersion on the other side. The double-sided coating led to higher multifunctionality. Furthermore, the optimized condition for the double-sided coating was investigated by using various NTO particles obtained using different ethanol-acetic acid ratios.

DOI： 10.1088/1361-6528/aab600

Scopus

PubMed

DOI： 10.11362/jcssjclayscience.22.1_1

Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

The synthesis of silver nanoparticles (AgNPs) within the interlayer space of transparent layered titania nanosheet (TNS) films is investigated. A considerable number of silver ions (approximate to 70% against the cation exchange capacity of the TNS) are intercalated in the TNS films using methyl-viologen-containing TNSs as a precursor. The silver ion (Ag+)-containing TNS films are treated with aqueous sodium tetrahydroborate (NaBH4), resulting in a gradual color change to bright blue. Various structural analyses clearly show that crystalline AgNPs are generated within the interlayer space of the TNSs. The NaBH4-treated films show intense and characteristic near-infrared (NIR) extinction spectra up to 1800 nm. The tability of the AgNPs within the TNS against oxygen and moisture is also investigated, and 96% and 82% of the AgNPs remain after standing in air for 1 month and 1 year, respectively. The NIR extinctions of the AgNP-containing TNS films are further extended by employing different preparation procedures, for example, using sintered TNS films as starting materials and irradiating the Ag+-containing TNSs with ultraviolet (UV) light. The obtained AgNP-containing TNS films exhibit photochemical activities in the production of hydrogen from ammonia borane under visible-light irradiation and the decomposition of nitrogen monoxide under UV-light irradiation.

DOI： 10.1002/gch2.201700105

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Ceramic Society of Japan  

SrTiO3 is an excellent photocatalyst due to its high photocorrosion resistance and thermal stability. In this study, we synthesized SrTiO3 nanoparticles with high specific surface areas by the hydrothermal method at reduced temperature. Titanium(IV) bis(ammonium lactato)dihydroxide (TALH) solution and strontium hydroxide octahydrate [Sr(OH)2·8H2O] were used as starting materials. SrTiO3 nanoparticles were directly synthesized by hydrothermal heating at 150°C for 72120 h. The synthesized nanoparticles had diameters of 2040 nm, and the SrTiO3 powder heated for 72 h exhibited the highest specific surface area of 33.1 m2/g. This sample also showed the highest degradation rate for NO gas.

DOI： 10.2109/jcersj2.17195

Scopus

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry  

Gallium oxynitride (GaON) nanoparticles were synthesized through three steps
(i) hydrothermal treatment of an aqueous solution containing Ga(NO3)3, hexamethylenetetramine (HMT), and acetylene black, (ii) calcination, and (iii) nitridation. The presence of acetylene black in the hydrothermal treatment is effective for the synthesis of Ga2O3 nanoparticles after the calcination. The intermediate obtained after the hydrothermal reaction possessed no detectable Ga particles in the TEM observation, although the presence of Ga was confirmed in the EDS measurement. This means that acetylene black (AB), in this study, cannot play a simple role as a template. The GaON nanoparticles obtained from the Ga2O3 nanoparticles through nitridation possessed a higher oxygen content than that from Ga2O3 obtained by hydrothermal synthesis without acetylene black and the subsequent calcination. The obtained GaON nanoparticles show higher photocatalytic NOx decomposition activity than bulk GaON synthesized under the same conditions except without acetylene black in the hydrothermal reaction, because of the longer absorption edge and the higher specific surface area. In addition, the effect of nitridation temperature and time on the obtained GaON nanoparticles and their photocatalytic activity was also investigated. Consequently, nanoparticle morphology of a precursor for GaON is important not only for high surface area but also for high visible-light response.

DOI： 10.1039/c7nr07502b

Scopus

PubMed

Language：English   Publishing type：Research paper (scientific journal)   Publisher：TAYLOR & FRANCIS LTD  

Direct nitridation process has been performed to synthesize morphology controllable aluminum nitrides (AlN). Three different morphologies of gamma-AlOOH were treated under NH3 flow at 1400 degrees C for 4 h. Hydrazine (N2H4) was employed in this study as a nitriding agent to promote nitridation reaction. In the presence of hydrazine, a high purity of aluminum nitride (AlN) could be achieved with less than 5 wt.% of oxygen impurities. Interestingly, after being exposed to elevated temperatures, the initial morphology was still retained. Whereas the TEM measurement indicated surface roughening due to the release of H2O. The investigation of sintering behavior of the prepared AlN powders revealed that plate-like morphology had the lowest shrinkage completing temperature (1574 degrees C).

DOI： 10.1080/21870764.2018.1439611

Web of Science

Language：English   Publishing type：Research paper (scientific journal)  

Publishing type：Research paper (scientific journal)  

© 2018 The Royal Society of Chemistry. Particulate Ta 3 N 5 , a material that responds to visible light for photoelectrochemical O 2 evolution, was glued to a metallic GaN conducting layer. The electrode was able to oxidize water with 1.8-fold higher efficiency than that without GaN. The GaN layer blocked the hole current from Ta 3 N 5 to the back-contact metal layer and prevented hole-electron recombination.

DOI： 10.1039/c7se00402h

Scopus

Language：English   Publishing type：Research paper (scientific journal)   Publisher：WORLD SCIENTIFIC PUBL CO PTE LTD  

Synthesis and characterization of functional nanoparticles and their applications for smart window are reviewed. Various kinds of nanomaterials and their composites are successfully synthesized by solvothermal process. Thin films on glass substrate can be fabricated by doctor blade method using nanoparticles as starting materials. The mixed valence state tungsten-based homogeneous nanomaterials possess excellent infrared (IR) light shielding properties, implying their potential applications for the heat ray shielding and indoor energy saving effect in summer. On the other hand, VO2 monoclinic-based nanoparticles possess smart and excellent thermochromic properties, show excellent heat ray shielding effect in summer and heating effect of winter indoors. Also, multifunctionality of thin films can be realized by fabricating the composites with various functional components, implying their potential applications for IR shielding, photocatalysis and self-cleaning at the same time. The design of composites and structure of thin films might result in the enhancement or properties of practice applications on window materials.

DOI： 10.1142/S1793604718300049

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Chemical Society of Japan  

We investigated a new one-pot synthesis method for β-TaON oxynitride using (C6N9H3)n (melon) as a solid nitrogen source. β-TaON single phase was obtained from Ta2O5 using melon heating under a separated and sealed condition in a quartz glass tube. The oxygen and nitrogen contents of prepared β-TaON were almost 100% of the theoretical values.

DOI： 10.1246/cl.180265

Scopus

Language：English   Publisher：SCIENCE PRESS  

Environmentally friendly soft chemical processes, including solvothermal/hydrothermal process and mechanochemical process, for the synthesis of mixed anion type visible-light induced photocatalysts are introduced in this review paper. Titania and strontium titanate based anion doped photocatalysts can be effectively prepared at such low-temperature as below 200 degrees C. Especially, the mechanochemical process is a useful method for the synthesis of various mixed ions doping functional materials at low temperatures. The mixed anion type photocatalytic compounds consisted of N/O, N/F/O, S/O, N/C/O, show excellent visible light absorption ability and photocatalytic activities, indicating the potential applications in environmental purifications. Full-spectra active long wavelength light induced photocatalyst, full-time active photocatalyst system and infrared radiation (IR) shielding multifunctional photocatalysts will be introduced also.

DOI： 10.1007/s11431-016-9022-9

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

Silica sodalite was obtained using topotactic conversion of layered silicate RUB-15 through stepwise processes that consisted of the control of stacking sequence of the layers, interlayer condensation by refluxing, and elimination of intercalated guest species. The interlayer condensation of RUB-15, in which acetic acid was pre-intercalated between the layers to control the stacking sequence, afforded a sodalite framework containing organic guest species by refluxing in N-methylformamide (NMF). The pre-intercalated acetic acid molecules were largely replaced with NMF. This formation process of silica sodalite containing large amounts of intercalated organic guest species is in clear contrast to the previously reported process that used direct calcination of an intercalation compound of layered RUB-15 accommodating acetic acid between the layers. Calcination of the condensed product provided sodalite with fewer defects than the directly calcined product, thus indicating the advantage of the stepwise process. The method reported here is useful for the preparation of pure silica sodalite with relatively low defects and plate-like morphology.

DOI： 10.1039/c7dt01287j

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

A single-crystalline macroporous layered silicate was obtained for the first time. Firstly, UTL-type zeolite with macropores was prepared hydrothermally under the presence of acetylene black as a macropore template and the subsequent calcination to remove the template. Double four-membered ring (d4r) units in the UTL framework were selectively dissolved to yield a layered silicate with macropores. Intercalation of tetrabutylammonium ions into the macroporous layered silicate is accelerated if compared with that into the same silicate without macropores, indicating the effectiveness of macropores due to easy diffusion. The layered silicate with macropores was converted into PCR-type zeolite with macropores, a hierarchically micro- and macroporous material, through interlayer condensation.

DOI： 10.1002/chem.201701504

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

An improved variation of highly active/durable O-2-evolving LaTiO2N powder-based photoelectrode has been fabricated by pre-cleaning the powder with mild polysulfonic acid and by homogeneous deposition of CoOx co-catalyst aided by microwave annealing. The treatment in aqueous solution of poly(4-styrene sulfonic acid) results in removal of surface LaTiO2N layers, forming fine pores in the crystallites. The CoOx co-catalyst by microwave deposition in Co(NH3)(6)Cl-3/ethylene glycol homogeneously covers the particle surface. The LaTiO2N powder is fabricated into particle-transferred electrodes on Ti thin film supported on solid substrate. The modified LaTiO2N grains on the electrode serve as a highly active O-2-evolving photoanode achieving 8.9 mA cm(-2) of the photocurrent density at 1.23 V versus reversible hydrogen electrode (RHE) in 0.1 M NaOH (pH 13) under solar-simulator irradiation Airmass 1.5 Global (AM 1.5G). The activity has been much improved, compared with conventional LaTiO2N treated in mineral acid or with CoOx deposited by impregnation. The new electrode also exhibits better durability in fixed-potential chronoamperometric tests under AM 1.5G irradiation.

DOI： 10.1002/smll.201601929

Web of Science

Language：Japanese  

CiNii Books

Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

Interlayer-condensed materials of protonated layered silicate (magadiite) are synthesized by refluxing in N-methylformamide (NMF) and the subsequent calcination. The obtained materials possess 2-3 times higher surface areas than calcined protonated magadiite, depending on the time of refluxing. NMF molecules in the interlayer spaces are converted to organic substances with higher thermal stability during the refluxing, which is useful for the control of the stacking sequence of silicate layers and for the following interlayer condensation to increase the microporosity. The microporosity of the material obtained by the treatment of protonated magadiite with NMF at r.t. and the subsequent calcination is similar to that of simply calcined protonated magadiite, indicating that the retention of thermally stable substances in the interlayer is critical for the increase in the pore volume and surface area of the derivative from magadiite. The method reported here will stimulate re-estimation of a large number of known layered silicate organic intercalation compounds as possible candidates for the preparation of porous silica by interlayer condensation.

DOI： 10.1246/bcsj.20150155

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER INST PHYSICS  

In low dimensional cesium silicate LDS-1 (monoclinic phase of CsHSi2O5), anomalous infrared absorption bands observed at 93, 155, 1210, and 1220 cm(-1) are assigned to the vibrational mode of protons, which contribute to the strong hydrogen bonding between terminal oxygen atoms of silicate chain (O-O distance = 2.45 angstrom). The integrated absorbance (oscillator strength) for those modes is drastically enhanced at low temperatures. The analysis of integrated absorbance employing two different anharmonic double-minimum potentials makes clear that proton tunneling through the potential barrier yields an energy splitting of the ground state. The absorption bands at 93 and 155 cm(-1), which correspond to the different vibrational modes of protons, are attributed to the optical transition between the splitting levels (excitation from the ground state (n = 0) to the first excited state (n = 1)). Moreover, the absorption bands at 1210 and 1220 cm(-1) are identified as the optical transition from the ground state (n = 0) to the third excited state (n = 3). Weak Coulomb interactions in between the adjacent protons generate two types of vibrational modes: symmetric mode (93 and 1210 cm(-1)) and asymmetric mode (155 and 1220 cm(-1)). The broad absorption at 100-600 cm(-1) reveals an emergence of collective mode due to the vibration of silicate chain coupled not only with the local oscillation of Cs+ but also with the proton oscillation relevant to the second excited state (n = 2). (C) 2015 AIP Publishing LLC.

DOI： 10.1063/1.4926445

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

A novel crystalline microporous material is synthesized by silylation of layered silicate RUB-51 with tetrachlorosilane (SiCl4), hydrolysis, and heat treatment for interlayer condensation. One SiCl4 molecule first undergoes ordered silylation with two confronting groups, Si-O- and Si OH, on the interlayer surfaces of RUB-51 (bidentate silylation). Hydrolysis of the unreacted Si-Cl groups of the immobilized silyl groups by a mixture of H2O and dimethyl sulfoxide (DMSO) affords geminal Si-OH groups on the surfaces without simultaneous interlayer condensation because of intercalation with DMSO. Subsequent heat treatment leads to condensation between neighboring layers, and the condensed material is composed of layers of RUB-51 displaced by a half-unit cell along the a axis. Hydroxyl groups are present after interlayer cross-linking, which is one of the unique features of the method using SiCl4. The obtained sample adsorbs CO2 molecules, while RUB-51 itself without silylation cannot. The amount of adsorbed CO2 on the microporous material is larger than that of CH4, suggesting the potential of this material as a separation medium between CO2 and CH4. This study indicates that the preparation of microporous materials, using layered silicates as a building block and various silylating agents, is useful for precise design of both porosity and functional groups on pore surfaces, which drastically affect the properties of crystalline microporous materials, including catalytic selectivity and separation capability.

DOI： 10.1021/cm5014224

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

AST-type zeolite with a plate morphology can be synthesized by topotactic conversion of a layered silicate (beta-helix-layered silicate; HLS) by using N,N-dimethylpropionamide (DPA) to control the layer stacking of silicate layers and the subsequent interlayer condensation. Treatment of HLS twice with 1) hydrochloric acid/ethanol and 2) dimethylsulfoxide (DMSO) are needed to remove interlayer hydrated Na ions and tetramethylammonium (TMA) ions in intralayer cup-like cavities (intracavity TMA ions), both of which are introduced during the preparation of HLS. The utilization of an amide molecule is effective for the control of the stacking sequence of silicate layers. This method could be applicable to various layered silicates that cannot be topotactically converted into three-dimensional networks by simple interlayer condensation by judicious choice of amide molecules.

DOI： 10.1002/chem.201303368

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Silica-based materials have found many applications in various fields. Alkoxysilanes have been most widely used as precursors. Fine structural control of silica-based materials has become increasingly important for tuning their properties and for developing new functions. In this perspective, utilization of alkoxysilyl groups has been reviewed from the viewpoint of designing siloxane-based nanomaterials. Alkoxy groups have generally been used only as eliminating groups in the sol-gel processing; however, recent research has shown that they are useful for molecular assembly, for generating pores, for linking nanobuiliding blocks, and for selective synthesis of new oligosiloxane compounds.

DOI： 10.1021/cm4023387

Web of Science

DOI： 10.20731/zeoraito.31.3.78

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

We demonstrate that the separation of two stages of interlayer condensation under refluxing and elimination of organic guests provides the optimal conditions for the formation of RWR-type zeolite from layered octosilicate. The obtained RWR-type zeolite has higher quality than any other RWR-type zeolite reported previously.

DOI： 10.1039/c3dt53533a

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

Layered silicate RUB-51 with half-sodalite cages was silylated with dichlorodimethylsilane and trichloromethylsilane. RUB-51, which possesses two confronting Si-O-/Si-OH groups on the interlayer surface, was reacted with bi/tri-functional silylating agents to induce bidentate silylation. RUB-51 silylated with dichlorodimethylsilane was delaminated through ultrasonication in cyclohexane. Layered octosilicate, which also possesses two confronting Si-O-/Si-OH groups to form a bidentate state, was reacted with the same silylating reagents. The comparison of these silylated products derived from two different layered silicates reveals that the structures of silylated interlayer surfaces are varied by the arrangement of the two Si-O-/Si-OH groups. Silylated RUB-51 possesses zigzag grooves on the layer surfaces which will be useful for silicate-based nanomaterials design.

DOI： 10.1246/bcsj.20110143

Web of Science

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Language：Japanese   Presentation type：Oral presentation (general)  

Language：English   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

Language：English   Presentation type：Oral presentation (general)  

Language：English   Presentation type：Oral presentation (general)  

Language：English   Presentation type：Oral presentation (invited, special)  

Language：English   Presentation type：Oral presentation (invited, special)  

Language：English   Presentation type：Poster presentation  

Language：English   Presentation type：Oral presentation (general)  

Language：English   Presentation type：Oral presentation (general)  

Language：English   Presentation type：Poster presentation  

Presentation type：Oral presentation (general)  

Language：English   Presentation type：Oral presentation (general)  

Presentation type：Oral presentation (invited, special)  

Language：English   Presentation type：Oral presentation (general)  

Language：English   Presentation type：Oral presentation (general)  

Language：English   Presentation type：Oral presentation (invited, special)  

Language：Japanese   Presentation type：Oral presentation (general)  

Language：English   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese  

Language：English   Presentation type：Poster presentation  

Language：Japanese   Presentation type：Oral presentation (general)  

Language：English   Presentation type：Oral presentation (general)  

Language：English   Presentation type：Oral presentation (invited, special)  

Language：English   Presentation type：Oral presentation (general)  

Language：English   Presentation type：Poster presentation  

Language：English   Presentation type：Oral presentation (general)  

Language：English   Presentation type：Oral presentation (general)  

Language：English   Presentation type：Oral presentation (invited, special)  

Language：English   Presentation type：Oral presentation (general)  

Language：English   Presentation type：Oral presentation (general)  

Language：English   Presentation type：Oral presentation (general)  

Language：English   Presentation type：Oral presentation (general)  

Language：English   Presentation type：Oral presentation (invited, special)  

Language：English   Presentation type：Poster presentation  

Language：English   Presentation type：Poster presentation  

Language：English   Presentation type：Oral presentation (general)  

Language：English   Presentation type：Poster presentation  

Language：English   Presentation type：Oral presentation (general)  

Language：English   Presentation type：Oral presentation (invited, special)  

Language：English   Presentation type：Oral presentation (general)  

Language：English   Presentation type：Oral presentation (general)  

Language：English   Presentation type：Oral presentation (general)  

Language：English   Presentation type：Oral presentation (general)  

Language：English   Presentation type：Poster presentation  

Language：English   Presentation type：Oral presentation (invited, special)  

Language：English   Presentation type：Oral presentation (invited, special)  

Language：English   Presentation type：Oral presentation (general)  

Language：English   Presentation type：Oral presentation (general)  

Language：English   Presentation type：Oral presentation (general)  

Language：English   Presentation type：Oral presentation (general)  

Language：English   Presentation type：Oral presentation (invited, special)  

Language：English   Presentation type：Oral presentation (general)  

Presentation type：Oral presentation (general)  

Language：English   Presentation type：Poster presentation  

Language：Japanese   Presentation type：Oral presentation (general)  

Language：English   Presentation type：Oral presentation (general)  

Language：English   Presentation type：Oral presentation (general)  

Language：English   Presentation type：Poster presentation  

Language：English   Presentation type：Oral presentation (general)  

Language：English  

Language：English   Presentation type：Poster presentation  

Language：English   Presentation type：Oral presentation (general)  

Language：English   Presentation type：Oral presentation (general)  

Language：English   Presentation type：Oral presentation (general)