Faculty Profiles - SAITO, Nagahiro

Papers - SAITO, Nagahiro

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Nitrogen-doped 3D porous graphene coupled with densely distributed CoO<inf>x</inf> nanoparticles for efficient multifunctional electrocatalysis and Zn-Air battery Open Access

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

Electrochimica Acta Vol. 420 2022.7

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

Highly efficient and low-cost multifunctional electrocatalysts play a crucial role in energy storage and conversion systems. Herein, a new strategy is developed based on a structured precursor to design and fabricate a hierarchical porous nitrogen doped graphene coupled with densely distributed CoO/Co3O4 heterostructure that exhibits outstanding multifunctional activities. With rational hybridization of graphene and bimetallic nanoparticles, the as-obtained NGPC@CoOx integrated densely distributed CoO/Co3O4 active nanoparticles to 3D interconnected hierarchical N-doped graphene mesh, which gives rise to a multifaceted capability for electron/ion transfer and redox catalyzing. The NGPC@CoOx possesses excellent durability with a superior E1/2 of 0.86 V for oxygen reduction reaction (ORR), and a relatively low potential for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) of 1.61 V, and -0.162 V at 10 mA cm−2, respectively. Additionally, the superior cycling durability and high power density of NGPC@CoOx-based zinc-air batteries (184.4 mW cm−2) further confirm the potential application of prototype devices. This work introduces a new perspective on developing efficient multifunctional electrocatalysts with a well-designed 3D structure anchored with densely distributed nanoparticles towards energy storage and conversion technologies.

DOI： 10.1016/j.electacta.2022.140432

Fundamentals of solution plasma for advanced materials synthesis Reviewed International coauthorship Open Access

Chokradjaroen C., Wang X., Niu J., Fan T., Saito N.

Materials Today Advances Vol. 14 2022.6

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

Solution plasma is an atmospheric nonequilibrium plasma generated by electrical discharge in liquid phase at room temperature. The plasma configurations, solutions, electrode materials, as well as the characteristics of the power supply can be easily tuned. Due to these features of the solution plasma, various sizes, shapes, compositions of products can be controlled, leading to the effective utilization in several applications, such as a novel catalyst for energy conversion. To accomplish the use of solution plasma as a promising tool for the synthesis and modification of advanced materials, fundamentals and applied knowledge related to the solution plasma should be reviewed and discussed. Therefore, in this review, fundamentals of plasma in liquid are explained relating to the solution plasma, and detailed advanced applications of solution plasma are organized. It is expected to give powerful knowledge to guide the researchers in designing plasma conditions and synthesizing catalysts for different applications in the future.

DOI： 10.1016/j.mtadv.2022.100244

Design of three-dimensional isotropic negative-refractive-index metamaterials with wideband response based on an effective-medium approach

Chang Q., Liu X., Wang Z., Saito N., Fan T.

Applied Physics A: Materials Science and Processing Vol. 128 ( 5 ) 2022.5

Language：English Publishing type：Research paper (scientific journal) Publisher：Applied Physics A: Materials Science and Processing

Negative-refractive-index metamaterials (NRIMs) can provide opportunities for many new applications, but they are difficult to manufacture, especially when forced to work at high frequencies and required to be three-dimensionally isotropic. By integrating an effective-medium approach into all-dielectric left-handed materials (LHMs) and utilizing self-assembly, we developed a method to design three-dimensional NRIMs that can work in high frequencies and are suitable for mass production. The NRIMs are composed of arrays of spheres that are made from artificial media, which are devised under the effective-medium method in advance. Two cases with different close-packed structures were studied for verification purposes. Finite element analysis showed that both cases can achieve negative refraction within 14.5–15.2 GHz (Ku band), which qualifies as wideband. Negative refraction was further confirmed by investigating the resonance mode of units in each model. Dispersion analysis demonstrated isotropism and consistent behaviors in all cases, indicating the robustness of these properties over disorder accompanied by self-assembly. The proposed NRIM model is intrinsically isotropic, three-dimensional, passive, mass-producible, machinable and thus readily applicable.

DOI： 10.1007/s00339-022-05573-2

Flexible, solid-state, fiber-network-reinforced composite solid electrolyte for long lifespan solid lithium-sulfurized polyacrylonitrile battery

Luo S., Zhao E., Gu Y., Saito N., Zhang Z., Yang L., Hirano S.i.

Nano Research Vol. 15 ( 4 ) page： 3290 - 3298 2022.4

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

Solid lithium-sulfur batteries (SLSBs) show potential for practical application due to their possibility for high energy density. However, SLSBs still face tough challenges such as the large interface impedance and lithium dendrite formation. Herein, a high-performance SLSB is demonstrated by using a fiber network reinforced Li6.75La3Zr1.75Ta0.25O12 (LLZTO) based composite solid electrolyte (CSE) in combination with sulfurized polyacrylonitrile (SPAN) cathode. The CSE consisting of an electrospun polyimide (PI) film, LLZTO ionically conducting filler and polyacrylonitrile (PAN) matrix, which is named as PI-PAN/LLZTO CSE, possesses high room-temperature ionic conductivity (2.75 × 10−4 S/cm), high Li+ migration number (tLi+) of 0.67 and good interfacial wettability. SPAN is utilized due to its unique electrochemical properties: reasonable electronic conductivity and no polysulfides shuttle effect. The CSE enables a highly stable Li plating/stripping cycle for over 600 h and good rate performance. Moreover, the assembled SLSB exhibits good cycle performance of accomplishing 120 cycles at 0.2 C with the capacity retention of 474 mAh/g, good rate properties and excellent long-term cycling stability with a high capacity retention of 86.49% from 15th to 1,000th cycles at 1.0 C. This work rationalizes our design concept and may guide the future development of SLSBs. [Figure not available: see fulltext.]

DOI： 10.1007/s12274-021-3981-z

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

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