Faculty Profiles - SAITO, Nagahiro

Papers - SAITO, Nagahiro

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Solution plasma process for synthesizing polydiacetylene materials: Toward industrial utilization of colorimetric sensors

Saymung R., Watthanaphanit A., Saito N., Traiphol N., Traiphol R.

Journal of Industrial and Engineering Chemistry Vol. 106 page： 243 - 252 2022.2

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Industrial and Engineering Chemistry

A new route for synthesizing polydiacetylene (PDA) is introduced. Plasma is generated in a liquid matrix through a pair of electrodes, producing the excited atomic or molecular species, radicals, and UV radiation. The products of solution plasma process (SPP) act as initiators to induce polymerization of diacetylene monomers. Our results demonstrate that irreversible thermochromic PDA and reversible thermochromic PDA/Zn2+/ZnO nanocomposite can be effectively synthesized. The addition of ethanol significantly increases the polymerization rate. These PDA materials can be fabricated into paper-based colorimetric sensors for detecting volatile organic solvents, acids, bases, and surfactants. This synthetic pathway could be applied for industrial-scale applications.

DOI： 10.1016/j.jiec.2021.10.035

Morphology control of ZnO nanostructures using Zn and W electrodes in solution plasma process Open Access

Kim K., Chae S., Masuda Y., Saito N.

Materials Letters Vol. 309 2022.2

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

The morphology of ZnO nanostructures was controlled by the type of electrodes used, without chemical additives in the solution plasma process. Nanorod and nanosheet-type ZnO were synthesized using Zn and W electrodes, respectively. In the solution plasma process, the ZnO nanostructure can be fabricated because of the unique reaction between ions and radicals at the plasma/liquid interface. During this reaction, ions generated from the metal electrode influence the morphology of ZnO by adsorption on the (0 0 1) facet. Zn(OH)42− ions promoted crystal growth in the [0 0 1] direction, resulting in a rod structure. In contrast, the sheet structure was formed owing to the inhibition of growth in the [0 0 1] direction by WO42− ions.

DOI： 10.1016/j.matlet.2021.131349

Synthesis of nitrogen-doped carbons from single-source precursors by solution plasma

Gasidit Panomsuwan, Chayanapat Chokradjaroen, Nagahiro Saito

Nanomaterials via Single-Source Precursors: Synthesis, Processing and Applications page： 475 - 505 2022.1

Language：English Publishing type：Part of collection (book)

Solution plasma processing is a bottom-up synthetic approach that can be employed for directly preparing nitrogen-doped carbons from single-source precursors with in situ nitrogen doping. Research efforts and interest in this topic have gained at a significant pace over the past years. This chapter provides an overview of solution plasma processing and recent progress on the synthesis of nitrogen-doped carbons from single-source precursors using this approach. The chapter starts by introducing the basic fundamentals of solution plasma and how to apply it in the synthesis of nitrogen-doped carbons. The effects of a solution plasma conditions and the type of precursors on the overall properties of nitrogen-doped carbons are summarized based on the important findings reported in the literature. A potential application of nitrogen-doped carbons as metal-free electrocatalysts for oxygen reduction reaction is explained and discussed in brief. At the end of the chapter, the remaining challenges and future prospects are highlighted for use in further studies. This chapter is intended to be generally informative and a useful guide for researchers who are new to this field.

DOI： 10.1016/B978-0-12-820340-8.00019-8

Asymmetric Porous and Highly Hydrophilic Sulfonated Cellulose/Biomembrane Functioning as a Separator in a Lithium-Ion Battery

Thiangtham S., Saito N., Manuspiya H.

ACS Applied Energy Materials 2022

Language：English Publishing type：Research paper (scientific journal) Publisher：ACS Applied Energy Materials

Biomembranes based on sulfonated cellulose (SC) blended with PLA/PBS composites were fabricated with different SC contents into polymer matrices. The obtained membranes were applied as separators in lithium-ion batteries (LIBs). The porosities of SC/biomembranes with 0.5, 1, and 2 wt % SC contents were estimated to be 66.6, 73.4, and 87.7%, respectively, which are significantly greater than that of the Celgard 2400 membrane, a commercial monolayer polypropylene (PP) separator membrane (42.1%). Due to its high porosity, hydrophilicity, and good interfacial compatibility with electrodes, the SC/biomembranes offer high electrolyte uptake and low interfacial resistance, leading to enhanced ionic conductivity. The cell with the 2 wt % SC/biomembrane also exhibited stable cycle performance and improved rate capacity, especially when discharged at the 0.2C rate. A 106 mAh/g capacity retention rate was achieved for a battery with the 2 wt % SC/biomembrane after 100 cycles at the 1C rate; meanwhile, the Celgard 2400 membrane exhibited a capacity of 81 mAh/g. These results show that SC has great innovative potential for use as a biofiller in biomembranes, which is suitable for LIB applications.

DOI： 10.1021/acsaem.2c00602

Au nanoparticle-decorated TiO<inf>2</inf>hollow fibers with enhanced visible-light photocatalytic activity toward dye degradation Open Access

Panomsuwan G., Wongcharoen S., Chokradcharoen C., Tipplook M., Jongprateep O., Saito N.

RSC Advances Vol. 12 ( 1 ) page： 193 - 200 2021.12

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

TiO2 hollow fibers (THF) were prepared by a template method using kapok as a biotemplate and subsequently decorated by plasmonic Au nanoparticles using a solution plasma process. The THF exhibited an anatase phase and a hollow structure with a mesoporous wall. Au nanoparticles with a diameter of about 5-10 nm were uniformly distributed on the THF surface. Au nanoparticles-decorated TiO2 hollow fibers (Au/THF) have enhanced photocatalytic activity toward methylene blue degradation under visible light-emitting diode (Vis-LED) as compared to pristine THF and P25. This could be attributed to combined effects including effective light-harvesting by a hollow structure, large surface area due to a mesoporous wall of THF, and visible-light absorption and efficient charge separation induced by Au nanoparticles. The Au/THF also showed good recyclability and separation ability.

DOI： 10.1039/d1ra07323k

Synergetic design of dopant-free defect-enriched 3D interconnected hierarchical porous graphene mesh for boosting oxygen reduction reaction Open Access

Zhao Y., Wang X., Guo X., Cheng D., Zhou H., Saito N., Fan T.

Carbon Vol. 184 page： 609 - 617 2021.10

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

To resolve Pt-dependency problems in energy convention systems, we provide an idea for construct a highly active 3D interconnected hierarchical porous graphene mesh (3D-PGM) with effective exposure active sites. By a facile controllable process through self-assembly and chemical etching of reduced-graphene oxide, synergetic enhancement of oxygen reduction reaction (ORR) performance from intrinsic activity to apparent activity was realized. The as-obtained materials exhibit 3D interconnected hierarchical porosity for efficient mass transport, a high surface defect content with increased numbers of active sites and a robust conductive network, leading to a comprehensive multiscale electron transfer capability that ultimately enhances the ORR catalytic activity. Incredibly, the alkaline ORR performance of as-obtained catalyst exhibits a 4-electron pathway reaction with an onset potential (Eonset) of 0.89 V, half-wave potential (E1/2) of 0.84 V, and a lower Tafel slope of 58 mV dec−1, showing activity comparable to that of Pt/C catalysts. Moreover, the as assembled primary Zn–air batteries (ZABs) demonstrate a higher power density (182.6 mW cm−2) and a higher specific capacity (809.1 mA h g−1) than the Pt/C-based counterpart. The outstanding electrochemical performance and facile fabrication techniques make this material a promising alternative to commercial Pt/C for renewable energy devices.

DOI： 10.1016/j.carbon.2021.08.066

Structure and properties of nanocarbons-encapsulated WC synthesized by solution plasma process in palm oils

Islam, MZ; Watthanaphanit, A; Chae, S; Niitsu, K; Saito, N

MATERIALS EXPRESS Vol. 11 ( 9 ) page： 1602 - 1607 2021.9

High electrical conductivity and oxidation reduction reaction activity of tungsten carbide/carbon nanocomposite synthesized from palm oil by solution plasma process

Islam, MZ; Watthanaphanit, A; Chae, S; Niitsu, K; Saito, N

MATERIALS EXPRESS Vol. 11 ( 9 ) page： 1587 - 1593 2021.9

Facile synthesis of ZnO nanobullets by solution plasma without chemical additives Open Access

Kim K., Chae S., Choi P.G., Itoh T., Saito N., Masuda Y.

RSC Advances Vol. 11 ( 43 ) page： 26785 - 26790 2021.7

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

ZnO nano-bullets were synthesized using solution plasma from only Zn electrode in water without any chemical agents. In this sustainable synthesis system, the rapid quenching reaction at the interface between the plasma/liquid phases facilitates the fast formation of nano-sized materials. The coil-to-pin type electrode geometry, which overcomes the discharge interruption owing to the electrode gap broadening of the typical pin-to-pin type enables the synthesis of numerous nanomaterials through a stable discharge for 1 h. The as-prepared samples exhibited a high crystalline ZnO structure without post calcination, and the length and width were 71.8 and 29.1 nm, respectively. The main exposed facet of ZnO nano-bullets was the (100) crystal facet, but interestingly, the (101) facet was confirmed at the inclined surfaces in the edges. The (101) crystal facet has an asymmetric Zn and O atom arrangement, and it could result in a focused electron density area with relatively high reactivity. Therefore, ZnO nano-bullets are promising materials for applications in advanced technologies.

DOI： 10.1039/d1ra05008g

Reduced Red Mud as the Solar Absorber for Solar-Driven Water Evaporation and Vapor-Electricity Generation

Wang P., Wang X., Chen S., Zhang J., Mu X., Chen Y., Sun Z., Wei A., Tian Y., Zhou J., Liang X., Miao L., Saito N.

ACS Applied Materials and Interfaces Vol. 13 ( 26 ) page： 30556 - 30564 2021.7

Language：English Publishing type：Research paper (scientific journal) Publisher：ACS Applied Materials and Interfaces

The emergent solar-driven water evaporation technology provides a reassuring scheme for red mud (RM) utilization in environment and materials science. With fewer restrictions on raw materials, wide availability of sheer quantity, and high complexity in chemical composition, the RM may be a promising candidate for solar absorbers. Here, we developed a novel solar absorber with reduced RM. It features favorable light absorption and photothermal conversion ability using biomass pyrolysis. When added to the polyvinyl alcohol and chitosan gel substrate, the light absorptance can reach 94.65%, while the corresponding evaporation rate is as high as 2.185 kg m-2 h-1 under an illumination density of 1 kW m-2. We further demonstrated its potential as an efficient solar absorber in the solar-driven water evaporation and the thermoelectric device to realize the stable and efficient coproduction of vapor and electricity.

DOI： 10.1021/acsami.1c05228

Cationic nitrogen-doped graphene as a p-type modifier for high-performance PEDOT:PSS hole transporters in organic solar cells

Lin H.S., Kaneko T., Ishikawa S., Jeon I., Chae S., Yana T., Saito N., Matsuo Y.

Japanese Journal of Applied Physics Vol. 60 ( 7 ) 2021.7

Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Journal of Applied Physics

This research paper reports the enhanced hole-transporting ability of widely utilized poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) achieved by applying cationic nitrogen-doped graphene (CNG) as a p-type modifier for efficient organic solar cells (OSCs). The power conversion efficiency (PCE) of the CNG-coated PEDOT:PSS-applied OSC reaches 2.76%, which is an increase of 40% compared to that of the pristine PEDOT:PSS-applied OSC (1.96%). The significantly enhanced performance is contributed by the increased hole-transporting ability, and the improved interfacial morphology of PEDOT:PSS, which affords high-quality active layers.

DOI： 10.35848/1347-4065/ac00fc

Facile in Situ Synthesis of Amphiphilic Carbon-Supported Pt: Innovative Catalyst Preparation for Proton Exchange Membrane Fuel Cells

Tipplook M., Panomsuwan G., Muta Y., Saito N.

ACS Applied Energy Materials Vol. 4 ( 6 ) page： 5606 - 5614 2021.6

Language：English Publishing type：Research paper (scientific journal) Publisher：ACS Applied Energy Materials

Carbon materials are widely utilized to support platinum (Pt) catalysts for proton exchange membrane fuel cells (PEMFCs). However, carbon surfaces generally promote hydrophobicity, which limits the transport of active species and lowers the efficiency of PEMFCs. Consequently, functional groups should be introduced on the carbon surface to create transport channels. One promising strategy is to modify the amphiphilic functional group on a carbon surface. In this study, the liquid-phase plasma process was applied to realizing a facile one-step synthesis of amphiphilic functional group-modified carbon-supported platinum (Am@C/Pt) to serve as a catalyst. This novel synthesis strategy provides several advantages over conventional processes, such as reducing the number of steps and minimizing the chemical and energy consumptions. Experimental results revealed that the PEMFCs' efficiency with Am@C/Pt is mainly controlled by the number of hydrophilic and hydrophobic characters on the carbon surface. A single PEMFC demonstrated a maximum current and power density of 2.41 A cm-2 and 1.68 W cm-2, respectively, at 0.7 V, which was significantly higher than those of commercially available carbon-supported Pt catalysts. Furthermore, Am@C/Pt demonstrated superior durability after 5000 test cycles.

DOI： 10.1021/acsaem.1c00406

Insight on solution plasma in aqueous solution and their application in modification of chitin and chitosan Open Access

Chokradjaroen C., Niu J., Panomsuwan G., Saito N.

International Journal of Molecular Sciences Vol. 22 ( 9 ) 2021.5

Language：English Publishing type：Research paper (scientific journal) Publisher：International Journal of Molecular Sciences

Sustainability and environmental concerns have persuaded researchers to explore renewable materials, such as nature-derived polysaccharides, and add value by changing chemical structures with the aim to possess specific properties, like biological properties. Meanwhile, finding methods and strategies that can lower hazardous chemicals, simplify production steps, reduce time consumption, and acquire high-purified products is an important task that requires attention. To break through these issues, electrical discharging in aqueous solutions at atmospheric pressure and room temperature, referred to as the “solution plasma process”, has been introduced as a novel process for modification of nature-derived polysaccharides like chitin and chitosan. This review reveals insight into the electrical discharge in aqueous solutions and scientific progress on their application in a modification of chitin and chitosan, including degradation and deacetylation. The influencing parameters in the plasma process are intensively explained in order to provide a guideline for the modification of not only chitin and chitosan but also other nature-derived polysaccharides, aiming to address economic aspects and environmental concerns.

DOI： 10.3390/ijms22094308

Deposition of carbon–tungsten carbide on coir pulp to improve its compatibility with polylactic acid

Boonyeun N., Rujiravanit R., Saito N.

Cellulose Vol. 28 ( 7 ) page： 4119 - 4136 2021.5

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

To increase hydrophobicity of surfaces of coir pulp, carbon–tungsten carbide (WC) was synthesized and simultaneously deposited on coir pulp by applying in-liquid electrical discharge plasma, so-called solution plasma process (SPP). As a result, water contact angle of carbon-WC deposited coir pulp was 123.4°, whereas that of coir pulp was 82.8°. The carbon-WC deposited coir pulp was then used as a filler in polylactic acid (PLA) to attain composite films of PLA/carbon-WC deposited coir pulp. The deposition of carbon-WC on coir pulp not only increased hydrophobicity of coir pulp but also improved compatibility between the filler and PLA. Even at the low filler content of 0.75 wt%, tensile strength and Young’s modulus of composite films of PLA/carbon-WC deposited coir pulp increased up to 45.73% and 22.79%, respectively compared with those of neat PLA film. Furthermore, the presence of carbon-WC deposited coir pulp in the PLA composite films could enhance the formation of crystalline structure of PLA. Accordingly, SPP is an interesting tool for surface modification of coir pulp in order to achieve surface-functionalized coir pulp for using as a filler in green composites. Graphic abstract: [Figure not available: see fulltext.]

DOI： 10.1007/s10570-021-03799-6

Li-air battery and ORR activity of nanocarbons produced with good synthesis rate by solution plasma process Reviewed Open Access

Islam M.Z., Watthanaphanit A., Chae S., Saito N.

Materials Advances Vol. 2 ( 8 ) page： 2636 - 2641 2021.4

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Materials Advances

Nanocarbons were successfully synthesized from benzene (BZ), nitro-benzene (BZ-NO2) and aniline (BZ-NH2) by solution plasma process (SPP). The SPP was generated by a bipolar pulsed power supply between two tungsten electrodes at room temperature. The synthesized nanocarbons were investigated. The highest synthesis rate, 40 mg min-1, was for the BZ nanocarbon. The transmission electron microscopy (TEM) morphology showed that the nanocarbon sizes were 15-25 nm. The Brunauer-Emmett-Teller (BET) analysis shows a highest surface area of 220 m2 g-1, pore size of 0.45 cm3 g-1, and average pore diameter of 20.0 nm for the BZ nanocarbon. Cyclic voltammetry (CV) in an acidic medium exhibited the oxygen reduction reaction (ORR) of the nanocarbons. The nanocarbon from BZ-NH2 obtained a high special capacity of 15 500 mA h per g of carbon at the discharge rate of 0.1 mA cm-2 with 1.0 mg carbon loading for the lithium (Li)-air battery. The ORR is an important reaction in Li-air batteries and fuel cells for the application of next-generation batteries and energy conversion devices.

DOI： 10.1039/d0ma00926a

Plasma-assisted synthesis of multicomponent nanoparticles containing carbon, tungsten carbide and silver as multifunctional filler for polylactic acid composite films Open Access

Boonyeun N., Rujiravanit R., Saito N.

Polymers Vol. 13 ( 7 ) 2021.4

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

Multicomponent nanoparticles containing carbon, tungsten carbide and silver (carbon-WC-Ag nanoparticles) were simply synthesized via in-liquid electrical discharge plasma, the so-called solution plasma process, by using tungsten electrodes immersed in palm oil containing droplets of AgNO3 solution as carbon and silver precursors, respectively. The atomic ratio of carbon:W:Ag in carbon-WC-Ag nanoparticles was 20:1:3. FE-SEM images revealed that the synthesized carbon-WC-Ag nanoparticles with particle sizes in the range of 20–400 nm had a spherical shape with a bumpy surface. TEM images of carbon-WC-Ag nanoparticles showed that tungsten carbide nanoparticles (WCNPs) and silver nanoparticles (AgNPs) with average particle sizes of 3.46 nm and 72.74 nm, respectively, were dispersed in amorphous carbon. The carbon-WC-Ag nanoparticles were used as multifunctional fillers for the preparation of polylactic acid (PLA) composite films, i.e., PLA/carbon-WC-Ag, by solution casting. Interestingly, the coexistence of WCNPs and AgNPs in carbon-WC-Ag nanoparticles provided a benefit for the co-nucleation ability of WCNPs and AgNPs, resulting in enhanced crystallization of PLA, as evidenced by the reduction in the cold crystallization temperature of PLA. At the low content of 1.23 wt% carbon-WC-Ag nanoparticles, the Young’s modulus and tensile strength of PLA/carbon-WC-Ag composite films were increased to 25.12% and 46.08%, respectively. Moreover, the PLA/carbon-WC-Ag composite films possessed antibacterial activities.

DOI： 10.3390/polym13070991

N-Doped few-layer graphene encapsulated Pt-based bimetallic nanoparticles: Via solution plasma as an efficient oxygen catalyst for the oxygen reduction reaction Open Access

Phan P.Q., Naraprawatphong R., Pornaroontham P., Park J., Chokradjaroen C., Saito N.

Materials Advances Vol. 2 ( 1 ) page： 322 - 335 2021

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

N-Doped few-layer graphene encapsulated Pt-based bimetallic nanoparticles were successfully synthesized via the solution plasma (SP) method. This synthesis strategy can be achieved in one pot by using only pure dimethylformamide (DMF) as the reaction solution at room temperature and atmospheric pressure. The structural analyses exhibited a fine core-shell structured nanoparticle (2-4 nm), which had Pt and Pt-based bimetallic nanoparticles as a core and N-doped few-layer graphene (NFG), having 2-4 layers, as a shell. Pt-based bimetallic cores (i.e., PtAu, PtAg, and PtPd) were varied depending on the metal electrodes used in the SP process. The electrocatalytic activity toward the oxygen reduction reaction (ORR) of the obtained samples in an acidic solution was found to be acceptable, while possessing excellent durability, compared to those of the commercial carbon-supported Pt catalyst. The effective ORR activity was possibly attributed to the synergistic effect of the Pt-based bimetallic core and N-doped graphene shell which contained high amounts of pyridinic-N and quaternary-N. The results in a single fuel cell test expressed the superiority of our SP-derived sample in the fuel cell performances to commercial Pt/C. This study not only proposed potential alternative ORR catalysts with acceptable electrocatalytic activity and high durability but also provided guidelines for the facile synthesis of carbon-based core-shell nanostructured materials with low chemical use via the SP process. This journal is

DOI： 10.1039/d0ma00718h

Natural Self-Confined Structure Effectively Suppressing Volume Expansion toward Advanced Lithium Storage Reviewed International coauthorship

Zhang Y., Huang J., Liao Z., Hu A., Li X., Saito N., Zhang Z., Yang L., Hirano S.I.

ACS Applied Materials and Interfaces 2021

Language：English Publishing type：Research paper (scientific journal) Publisher：ACS Applied Materials and Interfaces

Volume expansion hinders conversion-type transition-metal oxides (TMOs) as potential anode candidates for high-capacity lithium-ion batteries. While nanostructuring and nanosizing have been employed to improve the cycling stability of TMOs, we show here that both high initial Coulombic efficiency (ICE) and stable cycling reversibility are achieved in the layered compound Li0.9Nb0.9Mo1.1O6 (L0.9NMO) by inherent properties of the bulk crystal structure. In this model, MoO6 octahedra as active centers react with lithium ions and endow capacity, while a grid composed of NbO6 octahedra effectively suppresses the volume expansion, enhances the conductivity, and supports the structural skeleton from collapse. As a result, bulk L0.9NMO not only delivers a high discharge capacity of 1128 mA h g-1 at 100 mA g-1 with a considerable ICE of 87% but also exhibits long cycling stability and good rate performance (339 mA h g-1 after 500 cycles at 1 A g-1 with an average Coulombic efficiency approaching 100%). The self-confined structure provides a competitive strategy for stable conversion-type lithium storage.

DOI： 10.1021/acsami.1c02269

Safe, superionic conductive and flexible “polymer-in-plastic salts” electrolytes for dendrite-free lithium metal batteries

Liao Z., Huang J., Chen W., Saito N., Zhang Z., Yang L., Hirano S.i.

Energy Storage Materials Vol. 33 page： 442 - 451 2020.12

Language：English Publishing type：Research paper (scientific journal) Publisher：Energy Storage Materials

Solid polymer electrolytes (SPEs) garner tremendous attention for both enabling higher energy density battery chemistry and alleviating the safety concerns of liquid electrolytes, but the practical utilizations of SPEs are severely hindered by the limited room temperature ionic conductivity, low transference number and huge interface impedance. Unlike the polymer chain movement in traditional SPEs, in the present work, we develop novel “polymer-in-plastic salts” electrolytes (PIPSEs) via a high weight ratio of plastic salts to polymer in which polymer just function as framework so that non-flammable, superionic conductive and flexible SPEs can be obtained. Also, the high content of plastic salts in PIPSEs can wet electrodes and form compatible solid electrolyte interface (SEI) with lithium metal. As a consequence, solid-state dendrite-free symmetric Li cells with PIPSEs show ultralong cycle life over 1000 h under up to 2.0 mA cm−2 and Li/LiFePO4 and high-voltage Li/LiNi0.6Co0.2Mn0.2O2 cells utilizing above PIPSEs exhibit excellent cycle performance and appealing rate performance. It is anticipated that our work provides a new strategy for the next-generation solid-state batteries.

DOI： 10.1016/j.ensm.2020.09.003

Single-walled carbon nanotubes wrapped by cationic nitrogen-doped carbon for electrocatalytic applications Reviewed International coauthorship

Chae S., Phan P.Q., Panomsuwan G., Bratescu M.A., Hashimoto T., Teshima K., Saito N.

ACS Applied Nano Materials Vol. 3 ( 10 ) page： 10183 - 10189 2020.10

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：ACS Applied Nano Materials

The exploration of novel carbon material systems has emerged as a promising strategy for yielding unique and unconventional functional properties. In this study, a cationic nitrogen-doped carbonwrapped single-walled carbon nanotube (CN-C@SWCNT) was synthesized for the first time via solution plasma (SP) by using an aniline aqueous solution with the SWCNT dispersion under ambient conditions. The reactive species produced from SP led to the formation of cationic nitrogendoped carbon (CN-C) completely wrapped around SWCNT. Raman spectroscopy, electron diffraction, and X-ray photoelectron spectroscopy confirmed the presence of cationic nitrogen. CN-C@SWCNT exhibited an excellent electrical conductivity of 120.30 S cm-1. Room-temperature halleffect measurements revealed p-type semiconducting behavior for CN-C@ SWCNT, with a carrier concentration of 4.6 × 1020 cm-3. The electrical conductivity and carrier concentration of p-type CN-C@SWCNT were greater than those reported previously for carbon-based materials. The high electrical properties of CN-C@SWCNT were synergistically related to a conducting bridge between CN-C and SWCNT conducting domains and the presence of doped cationic nitrogen. The SP-synthesized CN-C@SWCNT demonstrates immense potential as an emerging class of p-type carbon materials in advanced electrocatalytic applications.

DOI： 10.1021/acsanm.0c02164

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