Phase engineering is an efficient strategy for enhancing the kinetics of electrocatalytic reactions.Herein,phase engineering was employed to prepare high‐performance phosphorous‐doped biphase(1T/2H)MoS_(2)(P‐BMS)na...Phase engineering is an efficient strategy for enhancing the kinetics of electrocatalytic reactions.Herein,phase engineering was employed to prepare high‐performance phosphorous‐doped biphase(1T/2H)MoS_(2)(P‐BMS)nanoflakes for hydrogen evolution reaction(HER).The doping of MoS_(2)with P atoms modifies its electronic structure and optimizes its electrocatalytic reaction kinetics,which significantly enhances its electrical conductivity and structural stability,which are verified by various characterization tools,including X‐ray photoelectron spectroscopy,high‐resolution transmission electron microscopy,X‐ray absorption near‐edge spectroscopy,and extended X‐ray absorption fine structure.Moreover,the hierarchically formed flakes of P‐BMS provide numerous catalytic surface‐active sites,which remarkably enhance its HER activity.The optimized P‐BMS electrocatalysts exhibit low overpotentials(60 and 72 mV at 10 mA cm^(−2))in H_(2)SO_(4)(0.5 M)and KOH(1.0 M),respectively.The mechanism of improving the HER activity of the material was systematically studied using density functional theory calculations and various electrochemical characterization techniques.This study has shown that phase engineering is a promising strategy for enhancing the H*adsorption of metal sulfides.展开更多
Density functional theory （DFT） calculations are employed to explore the NO2-sensing mechanisms of pure and Ti-doped WO3 （002） surfaces. When Ti is doped into the WO3 surface, two substitution models are considere...Density functional theory （DFT） calculations are employed to explore the NO2-sensing mechanisms of pure and Ti-doped WO3 （002） surfaces. When Ti is doped into the WO3 surface, two substitution models are considered： substitution of Ti for W6c and substitution of Ti for Wsc. The results reveal that substitution of Ti for 5-fold W forms a stable doping structure, and doping induces some new electronic states in the band gap, which may lead to changes in the surface properties. Four top adsorption models of NO2 on pure and Ti-doped WO3 （002） surfaces are investigated： adsorptions on 5-fold W （Ti）, on 6-fold W, on bridging oxygen, and on plane oxygen. The most stable and likely NO2 adsorption structures are both N-end oriented to the surface bridge oxygen Olc site. By comparing the adsorption energy and the electronic population, it is found that Ti doping can enhance the adsorption of NO2, which theoretically proves the experimental observation that Ti doping can greatly increase the WO3 gas sensor sensitivity to NO2 gas.展开更多
基金National Natural Science Foundation of China,Grant/Award Number:NSFC‐U1904215National Research Foundation of Korea,Grant/Award Number:2021R1A2C2012127。
文摘Phase engineering is an efficient strategy for enhancing the kinetics of electrocatalytic reactions.Herein,phase engineering was employed to prepare high‐performance phosphorous‐doped biphase(1T/2H)MoS_(2)(P‐BMS)nanoflakes for hydrogen evolution reaction(HER).The doping of MoS_(2)with P atoms modifies its electronic structure and optimizes its electrocatalytic reaction kinetics,which significantly enhances its electrical conductivity and structural stability,which are verified by various characterization tools,including X‐ray photoelectron spectroscopy,high‐resolution transmission electron microscopy,X‐ray absorption near‐edge spectroscopy,and extended X‐ray absorption fine structure.Moreover,the hierarchically formed flakes of P‐BMS provide numerous catalytic surface‐active sites,which remarkably enhance its HER activity.The optimized P‐BMS electrocatalysts exhibit low overpotentials(60 and 72 mV at 10 mA cm^(−2))in H_(2)SO_(4)(0.5 M)and KOH(1.0 M),respectively.The mechanism of improving the HER activity of the material was systematically studied using density functional theory calculations and various electrochemical characterization techniques.This study has shown that phase engineering is a promising strategy for enhancing the H*adsorption of metal sulfides.
基金supported by the National Natural Science Foundation of China (Grant Nos. 60771019 and 60801018)Tianjin Key Research Program of Application Foundation and Advanced Technology, China (Grant No. 11JCZDJC15300)+1 种基金Tianjin Natural Science Foundation, China (Grant No. 09JCYBJC01100)the New Teacher Foundation of the Ministry of Education, China(Grant No. 200800561109)
文摘Density functional theory （DFT） calculations are employed to explore the NO2-sensing mechanisms of pure and Ti-doped WO3 （002） surfaces. When Ti is doped into the WO3 surface, two substitution models are considered： substitution of Ti for W6c and substitution of Ti for Wsc. The results reveal that substitution of Ti for 5-fold W forms a stable doping structure, and doping induces some new electronic states in the band gap, which may lead to changes in the surface properties. Four top adsorption models of NO2 on pure and Ti-doped WO3 （002） surfaces are investigated： adsorptions on 5-fold W （Ti）, on 6-fold W, on bridging oxygen, and on plane oxygen. The most stable and likely NO2 adsorption structures are both N-end oriented to the surface bridge oxygen Olc site. By comparing the adsorption energy and the electronic population, it is found that Ti doping can enhance the adsorption of NO2, which theoretically proves the experimental observation that Ti doping can greatly increase the WO3 gas sensor sensitivity to NO2 gas.
