Mixtures of W and B13C2 powders were mechanically milled and subsequently annealed at 900-1200℃.It is found that amorphous W-B-C alloy formed as the mixtures were milled for 20.80 h.After annealing the 80 h-milled mi...Mixtures of W and B13C2 powders were mechanically milled and subsequently annealed at 900-1200℃.It is found that amorphous W-B-C alloy formed as the mixtures were milled for 20.80 h.After annealing the 80 h-milled mixtures at 900-950℃,solid solutions of C and/or B in tungsten[W（B,C）],C in tungsten boride[W2B（C）or WB（C）]formed by the crystallization of amorphous W-B-C.The formation temperature of W2B（C）and WB（C）is lower than that of W2B and WB reported previously.As the 80 h-milled mixtures were annealed at 1200℃,W reacted with amorphous W-B-C completely to form WB and W2B5 or W2B5 instead of the solid solutions of C in tungsten borides,which is determined by the mole ratio of W to B13C2.The formation mechanisms of the W2B（C）and WB（C）solid solutions as well as phase transition rules of the mixtures at annealing temperature and mole ratio were also investigated using first-principle calculation.展开更多
The d-band centers of catalysts have exhibited excellent performance in various reactions.Among them,the enhanced catalytic reaction is considered a crucial way to power dynamics and reduce the“shuttle”effect in pol...The d-band centers of catalysts have exhibited excellent performance in various reactions.Among them,the enhanced catalytic reaction is considered a crucial way to power dynamics and reduce the“shuttle”effect in polysulfide conversions of lithium-sulfur batteries.Here,we report two-dimensional-shaped tungsten borides(WB)nanosheets with d-band centers,where the d orbits of W atoms on the(001)facets show greatly promoting the electrocatalytic sulfur reduction reaction.As-prepared WB-based Li-S cells exhibit excellent electrochemical performance for Li-ion storage.Especially,it delivers superior capacities of 7.7 mAh/cm^(2) under the 8.0 mg/cm^(2) sulfur loading,which is far superior to most other electrode catalysts.This study provides insights into the d-band centers as a promising catalyst of twodimensional boride materials.展开更多
Tungsten boride(WB) crystals, whose surface tends to be oxidized when exposed to air, were demonstrated to have a comparable activity to platinum as counter electrode material in dye-sensitized solar cells. The synerg...Tungsten boride(WB) crystals, whose surface tends to be oxidized when exposed to air, were demonstrated to have a comparable activity to platinum as counter electrode material in dye-sensitized solar cells. The synergistic effect of both catalytically active surface layer WOxand electronically conductive internal WB is considered to be responsible for the high activity of the WB crystals.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.11274135,11074093,61205038)the Specialized Research Fund for the Doctoral Program of Higher Education(Grant No.20130061130011)+2 种基金the Ph.D Programs Foundation of Ministry of Education of China(Grant No.20120061120011)the Science and Technology Development Project of Jilin Province,China(Grant No.20170101142JC)supported by High Performance Computing Center of Jilin University,China
文摘Mixtures of W and B13C2 powders were mechanically milled and subsequently annealed at 900-1200℃.It is found that amorphous W-B-C alloy formed as the mixtures were milled for 20.80 h.After annealing the 80 h-milled mixtures at 900-950℃,solid solutions of C and/or B in tungsten[W（B,C）],C in tungsten boride[W2B（C）or WB（C）]formed by the crystallization of amorphous W-B-C.The formation temperature of W2B（C）and WB（C）is lower than that of W2B and WB reported previously.As the 80 h-milled mixtures were annealed at 1200℃,W reacted with amorphous W-B-C completely to form WB and W2B5 or W2B5 instead of the solid solutions of C in tungsten borides,which is determined by the mole ratio of W to B13C2.The formation mechanisms of the W2B（C）and WB（C）solid solutions as well as phase transition rules of the mixtures at annealing temperature and mole ratio were also investigated using first-principle calculation.
基金supported by the National Natural Science Foundation of China(Nos.61904080,22205101)the Natural Science Foundation of Jiangsu Province(No.BK20190670)+5 种基金the Natural Science Foundation of Colleges and Universities in Jiangsu Province(No.19KJB530008)the Macao Young Scholars Program(No.AM2020005)the High-Performance Computing Cluster(HPCC)of Information and Communication Technology Office(ICTO)at University of Macao,Science and Technology Development Fund,Macao SAR(Nos.0191/2017/A3,0041/2019/A1,0046/2019/AFJ,0021/2019/AIR)University of Macao(Nos.MYRG2017-00216-FST and MYRG2018-00192-IAPME),FDCT Funding Scheme for Postdoctoral Researchers(No.0026/APD/2021)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)the UEA funding,and Guangdong Basic and Applied Basic Research Foundation(No.2022A1515110994).
文摘The d-band centers of catalysts have exhibited excellent performance in various reactions.Among them,the enhanced catalytic reaction is considered a crucial way to power dynamics and reduce the“shuttle”effect in polysulfide conversions of lithium-sulfur batteries.Here,we report two-dimensional-shaped tungsten borides(WB)nanosheets with d-band centers,where the d orbits of W atoms on the(001)facets show greatly promoting the electrocatalytic sulfur reduction reaction.As-prepared WB-based Li-S cells exhibit excellent electrochemical performance for Li-ion storage.Especially,it delivers superior capacities of 7.7 mAh/cm^(2) under the 8.0 mg/cm^(2) sulfur loading,which is far superior to most other electrode catalysts.This study provides insights into the d-band centers as a promising catalyst of twodimensional boride materials.
基金supported by the National Basic Research Program of China(2014CB239401)the National Natural Science Foundation of China(51422210,51629201,51521091)
文摘Tungsten boride(WB) crystals, whose surface tends to be oxidized when exposed to air, were demonstrated to have a comparable activity to platinum as counter electrode material in dye-sensitized solar cells. The synergistic effect of both catalytically active surface layer WOxand electronically conductive internal WB is considered to be responsible for the high activity of the WB crystals.
