Catalysis Science & Technology
·
2013
·Vol. 3
·期 8
·2104-2112
·
IF 3.753
Shuguo Wang,Zehui Zhang,Bing Liu,Jinlin Li
In this study, a magnetically-recoverable catalyst (Fe3O4@SiO2-HPW) was prepared by the application of phosphotungstic acid (HPW) supported on silica-coated Fe3O4 nanoparticles. The prepared samples were characterized by XRD, TEM, FT-IR, and N2-adsorption–desorption isotherms. The content of W in Fe3O4@SiO2-HPW was measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES) and its surface acidity was determined by a potentiometric titration with n-butylamine. Fe3O4@SiO2-HPW showed an excellent catalytic activity for the synthesis of EMF from HMF and fructose. Under optimal reaction conditions, EMF was obtained in a high yield of 83.6% by the etherification of 5-hydroxymethylfurfural. EMF could also be synthesized directly from fructose in a yield of 54.8% via a one-pot reaction strategy. After reaction, the catalyst Fe3O4@SiO2-HPW could be easily separated from the reaction mixture with an external magnetic field, and it could be reused at least five times without any loss of its catalytic activity.
研究领域:
化学
·
催化材料科学
✓ 已验证
DOI
高影响因子
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE
·
2019
·Vol. 50
·期 10
·4827-4838
·
IF 1.985
Liu Jun-Kai,Zhang Guo-Hua,Sun Guo-Dong
We propose a process to produce ultrafine W-10 wt pct Cu composite powders by reducing the mixtures of copper tungstate (CuWO 4 ) and tungsten trioxide (WO 3 ) (from the calcination of a mixture of ammonium paratungstate and copper nitrate trihydrate) with carbon black and hydrogen. First, ultrafine pre-reduced tungsten-copper (W-Cu) powders containing a small amount of WO 2 were produced by reducing mixtures of CuWO 4 and WO 3 with insufficient carbon black; then the obtained products were further reduced by hydrogen to remove the residual oxygen. This method provides a simple and low-cost route to prepare ultrafine W-10 wt pct Cu composite powders. The composite powders were sintered at different temperatures [1323 K (1050 °C), 1373 K (1100 °C), 1423 K (1150 °C), 1473 K (1200 °C), and 1523 K (1250 °C)] for 3 hours. A maximum densification of the obtained compact was achieved at a sintering temperature of 1523 K (1250 °C), with a relative density, Vickers hardness and thermal conductivity of the W-10 wt pct Cu composites of 97.8 pct, 365 HV and 165 W/m K, respectively.
研究领域:
材料科学
·
冶金工程
✓ 已验证
DOI
高影响因子
Cell Reports Physical Science
·
2021
·
IF 0
Weihong Li,Chongjia Lin,Wei Ma,Yang Li,Fuqiang Chu,Baoling Huang,Shuhuai Yao
Surface fogging reduces light transmission of optically clear materials and causes various problems in daily life. Transparent photothermal materials have recently emerged as an eco-friendly and sustainable solution to surface fogging. However, most reported photothermal materials only exploited the broadband spectrum of solar energy, and the spectral feature has yet to be tuned to optimize the visibility and photothermal effect simultaneously. Here, we develop a highly transparent, photothermally selective coating, based on solution-processed cesium-doped tungsten trioxide nanoparticles. The transparent selective photothermal coating provides a visible transmittance up to 82% and a high absorption of ultraviolet and near-infrared light >90%, and achieves a temperature increase by 38°C under 1-sun illumination, resulting in remarkable antifogging and defogging abilities under extremely frigid or humid conditions. Large-scale complex surfaces with photothermal coatings are deployed in field antifogging tests as well as long-term durability tests, showing their great potential in antifogging applications.
研究领域:
材料科学
·
能源科学
·
光学工程
✓ 已验证
DOI
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2020
·
IF 3.99
Binglong Yu,Jie Wang,Xiaoyun Mo,Xiaoxin Yang,Wenlong Wang,Xiulan Cai
Tungsten oxide (WO x ) is an important n-type semiconductor, which has attracted wide attention in the fields of gas sensing materials, photocatalysis , photoluminescence and electrochemistry due to its excellent electro-optical properties. However, the application potential of WO x -based nanomaterials in biomedicine has been neglected. In this paper, we firstly synthesized tungsten oxide nanowires (WO x NWs) by one-step method using tungsten chloride and triethylene glycol as raw materials, and reported an effective surface engineering strategy for polyglycerol-functionalized tungsten oxide nanowires (WO x -PG) to enhance their colloidal stability, biocompatibility , and selective toxicity to specific cancer cells in dispersion media . The WO x -PG was further derivatized and covalently combined with FA (WO x -PG-FA) as a drug targeting vector to deliver doxorubicin (DOX) to cancer cells. Compared with WO x NWs, WO x -PG exhibits smaller size (30−90 nm), more uniform distribution, better solubility and biocompatibility. The hemolysis rate of PG-modified WO x NWs was significantly reduced, being only 1.35 % at 200 μg/ml. The in vitro drug release percentage of WO x -PG-FA/DOX reached 80.78 % within 48 h at pH 5.2. In vitro toxicity assays and confocal laser scanning microscope (CLSM) results indicated that PG-functionalized WO x NWs were not cytotoxic, and WO x -PG-FA/DOX had highly selective cytotoxicity on HeLa cells. These results indicate that WO x -PG-FA is a potential drug carrier for effective targeting of cancer therapy.
研究领域:
材料科学
·
生物医学工程
·
药学
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry A
·
2022
·Vol. 10
·期 14
·7694-7704
·
IF 14.511
Xiaoyan Wang,Jia Bo Le,Yang Fei,Ruiqin Gao,Maoxiang Jing,Weiyong Yuan,Chang Ming Li
In situ mixing of transition metal phosphides (TMPs), especially those with dissimilar metals, in ultrasmall spaces and assembling them on nanoscale supports for remarkably enhanced hydrogen evolution reaction (HER) activity are rather challenging. We have fabricated pristine graphenesupported ultrasmall, highly dispersed, and high-density Co–W–P nanoparticles (NPs) via phosphotungstic acid-mediated self-assembly. This nanohybrid exhibits outstanding activity with all of the onset overpotential, overpotential (10 mA cm−2), Tafel slope, and exchange current density in both 0.5 M H2SO4 and 1 M KOH superior to those of most reported non-noble-metal-based catalysts and excellent durability showing negligible current change after 24 h chronoamperometric measurement and after 2000 CV cycles. The superior catalytic performance is ascribed to in situ intimately grown Co–W–P NPs with ultrasmall sizes and high dispersion greatly promoting electron transfer, ultrasmall and well-dispersed Co–W–P NPs on graphene providing numerous electrochemically accessible active sites, and synergistic interaction between WP2 and CoP significantly enhancing intrinsic activity. This work not only develops a facile and economical strategy to synthesize pristine graphene supported mixed phosphides of dissimilar transition metals as low-cost and high-performance HER electrocatalysts, but sheds light on synergistic effects between TMPs for high activity and self-assembly mechanisms toward the synthesis of various unique nanohybrids.
研究领域:
材料科学
·
电化学
·
纳米技术
✓ 已验证
DOI
高影响因子
Electronic Materials Letters
·
2024
·Vol. 20
·期 4
·459-473
·
IF 2.1
Tang Jing,Xu Hui,Chen Yong,Zhu Yuanqiang
Currently, transition metal tungstates are emerging as electroactive materials for supercapacitors due to their excellent electrical conductivity and electrochemical properties. Small amounts of transition metal ions doping can affect the physical and electrical properties of transition metal tungstates. In this study, Co ion-doped NiWO 4 amorphous composites (CNWO) were synthesized using a simple and effective hydrothermal method and utilized as the cathode material for supercapacitors. The structure and electrochemical properties of NiWO 4 and CNWO composites were investigated using various testing techniques. Specifically, when the cobalt ion doping amount is 10%, the corresponding CNWO-10 electrode material exhibits a specific capacitance of 804 F g −1 at 1 A g −1 , and at a current density of 10 A g −1 , the capacitance retention rate reaches 66.7%, demonstrating good rate performance. Additionally, an asymmetric supercapacitor device was constructed using CNWO-10 and activated carbon (AC) as positive and negative materials, respectively. Which could cycle reversibly under a potential window of 2.1 V. The device demonstrates a maximum specific capacitance of 76.5 F g −1 at 0.5 A g −1 , and a high energy density of 47 Wh kg −1 at a power density of 527 W kg −1 . Furthermore, 96% capacitance cycling stability is maintained after 5500 cycles at a trapezoidal current density. Moreover, the electrical conductivities of NiWO 4 and CNWO-10 samples are 9.01 × 10 –8 S m −1 and 8.93 × 10 –6 S m −1 , attributed to the Co ion-doping that can reduce the gap width of the forbidden band to enhance conductivity. These results suggest that CNWO composites can serve as promising high-capacity electrode materials for high-performance supercapacitors in alkaline electrolytes. Graphical Abstract
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
FUEL PROCESSING TECHNOLOGY
·
2024
·
IF 7.2
Yan Gao,Shuhong Jia,Hongyan Zhou,Ziyun Chen,Miao Yan,Jianshe Zhao
s An efficient and sustainable catalyst is urgently needed for the actual oil refining process. Different amounts of peroxophosphotungstate (PW 4 ) were successfully encapsulated into the pore of ZIF-8 framework material to obtain composites (x%-PW 4 @ZIF-8, x = 10.7, 14.6, 27.5 and 34.8) through a stirring process at room temperature for desulfurization of model diesel. The successful encapsulation of the active component PW 4 in the pore was verified by a variety of characterization methods, and there is weak force between the PW 4 and the ZIF-8. The composite 27.5%-PW 4 @ZIF-8 showed good catalytic activity for various sulfides under moderate conditions. In addition, DBT removal rate catalyzed by 27.5%-PW 4 @ZIF-8 could still reach levels of 95.1% after 10 cycles. The high efficiency of activity and excellent reusability are attributed to the high matching of host and guest sizes. This work provides new inspiration for designing and preparing catalysts with high activity and excellent reusability by a simple and environmentally friendly method.
研究领域:
化学工程
·
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
SOLID STATE IONICS
·
2017
·
IF 2.354
Feng Zhang,Tingting Zhang,Xiaoqin Zou,Xiaoqiang Liang,Guangshan Zhu,Fengyu Qu
It is a big challenge to construct proton-conductive metal organic framework (MOF) films for successful utilization of MOF materials in proton-conducting devices. Herein, we propose an electrochemical strategy for the preparation of highly porous NENU-3 films on the conductive copper substrates . The Keggin-type heteropolyacid of phosphotungstic acid (PTA) as the molecular clusters is integrated into Cu 3 (BTC) 2 cavities by the one-step electrochemical approach. The PTA plays a dual role of guest molecules in the cages as well as a strong electrolyte in the synthesis solution. Further, as-prepared NENU-3 films exhibit a fascinating proton conductivity under ~ 97% RH and at 24 °C, possibly originating from the Keggin PTA clusters, as proton carriers and the hydrophilic framework of Cu 2 (BTC) 3 . This study may offer a new strategy to assemble the proton-conductive MOF films, and the good combination of heteropolyacids and MOF host materials presents a promising platform for expanding the applications of MOFs in electrochemical devices .
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
OPTICAL MATERIALS
·
2024
·
IF 3.8
Zulfiqar Ali,Fei Hu,Muhammad Sohail,Intikhab Alam,Nimra Razzaq,Qiuyun Ouyang
The Bi 2 WO 6 /ZnO (BWO/ZnO) composites were synthesized by using a hydrothermal method. Then, the BWO/ZnO composites were poured into methyl methacrylate through polymerization to make the BWO/ZnO/PMMA organic glasses (OGs) with different amounts. The X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to investigate the crystal structures and morphology size of BWO/ZnO composites. The nonlinear absorption (NLA), nonlinear refraction (NLR) and optical limiting (OL) properties were systematically investigated by using the Z-scan technique at 532 nm. The BWO/PMMA and BWO/ZnO/PMMA OGs may transform from saturable absorption (SA) to reverse saturable absorption (RSA) by varying the input energy. The NLA, NLR and OL performances of the BWO/ZnO/PMMA OGs are superior to those of the BWO/PMMA OGs and other bismuth-based metal oxides. The synergistic interaction of BWO and ZnO plays a crucial role in the BWO/ZnO/PMMA OGs. The NLA mechanisms were analyzed using an energy-level model.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
Microsystems & Nanoengineering
·
2024
·Vol. 10
·期 1
·1-10
·
IF 7.3
Guan Kejie,Li Yinxiao,Liu Lin,Sun Fuqin,Wang Yingyi,Zheng Zhuo,Zhou Weifan,Zhang Cheng,Cai Zhengyang,Wang Xiaowei,Feng Simin,Zhang Ting
Owing to the controllable growth and large-area synthesis for high-density integration, interest in employing atomically thin two-dimensional (2D) transition-metal dichalcogenides (TMDCs) for synaptic transistors is increasing. In particular, substitutional doping of 2D materials allows flexible modulation of material physical properties, facilitating precise control in defect engineering for eventual synaptic plasticity. In this study, to increase the switch ratio of synaptic transistors, we selectively performed experiments on WS 2 and introduced niobium (Nb) atoms to serve as the channel material. The Nb atoms were substitutionally doped at the W sites, forming a uniform distribution across the entire flakes. The synaptic transistor devices exhibited an improved switch ratio of 10 3 , 100 times larger than that of devices prepared with undoped WS 2 . The Nb atoms in WS 2 play crucial roles in trapping and detrapping electrons. The modulation of channel conductivity achieved through the gate effectively simulates synaptic potentiation, inhibition, and repetitive learning processes. The Nb-WS 2 synaptic transistor achieves 92.30% recognition accuracy on the Modified National Institute of Standards and Technology (MNIST) handwritten digit dataset after 125 training iterations. This study’s contribution extends to a pragmatic and accessible atomic doping methodology, elucidating the strategies underlying doping techniques for channel materials in synaptic transistors.
研究领域:
材料科学
·
神经网络
·
电子工程
✓ 已验证
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2024
·
IF 6.3
Min Liu,Teng Zhang,Yuanzheng Xia,Jiangpeng Zhou,Mengyu Liu,Yuxiang Zhang,Feiya Xu,Yiyan Cao,Chunmiao Zhang,Xuanli Zheng,Yaping Wu,Zhiming Wu,Xu Li,Junyong Kang
The bilayer (BL) transition metal dichalcogenides (TMDs), with their elevated carrier mobility and narrowed bandgap, are advantageous for future electronic applications in comparison with their monolayer (ML) counterparts. Here, we introduce a facile and efficient approach for the chemical vapor deposition synthesis of BL WS 2 . The method involves an acetic acid sonication treatment to modify the substrate surface morphology and the surface energy, which regulates the nucleation processes and shapes the growth mode of WS 2 crystals. Further modifications to the growth conditions yield high-quality ML and BL WS 2 films. A comparative study confirms the superior valley polarization and higher carrier mobility of BL WS 2 compared with its ML counterpart. Additionally, a minor twist angle existed between the upper and lower layers, featuring a Moiré superlattice. This work reveals the role of surface morphology and surface energy in the growth of TMDs. Simultaneously, it offers insights into the controlled preparation of vertically stacked homo- and heterojunctions.
研究领域:
材料科学
·
表面化学
·
电子器件
✓ 已验证
DOI
高影响因子
CATALYSIS TODAY
·
2018
·
IF 4.667
Dawang Chu,Chen Zhao
The effective and selective conversion of cellulose to valuable fuels and chemicals is highly attractive. In this paper, we prepared a catalyst with the adjacent surface Cu° and oxygen-deficient WO x (2 < x < 3) species by reduction of CuWO 4 precursor, and such catalyst coupled with Ni/activated carbon (AC) attained high yield (71 wt%) and good cycling performances in catalyzing one-step hydrothermal conversion of cellulose to ethylene glycol (EG), highly superior to the performances on physically mixed Ni/C, Cu/C and WO 3 . The increased Cu doping amounts led to a higher ratio of the lower valence state W (V or IV) to the high valence W(VI) as indicated by XPS, XRD, and TPR-H 2 analyses. The oxygen vacancies on the hydrogen-reduced CuWO 4 sample dramatically increased, probably due to the benefits from the substantial dissociated H• on the neighboring Cu° center. The EG yields from cellulose are shown to be proportional to the concentrations of oxygen vacancies on WO x , which catalyzes the important elementary retro-aldol step reaction via adsorbing C 6 sugar intermediates in a specific way. It is inferred that Cu introduction is mainly used to create more oxygen vacancies on the WO x surface that helps adsorbing oxygenates, while Ni fast hydrogenates of hydroxyacetaldehyde to EG and avoids coking, constructing a multi-functional synergistic catalytic process from converting of cellulose to EG in the high-temperature water
研究领域:
催化化学
·
生物质转化
·
绿色化学
·
材料化学
·
能源化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）