1T phase MoS_(2)(1T-MoS_(2)) is a promising substitute of platinum electrocatalyst for hydrogen evolution reaction(HER)due to its high intrinsic activity but suffering from thermodynamical instability.Although great e...1T phase MoS_(2)(1T-MoS_(2)) is a promising substitute of platinum electrocatalyst for hydrogen evolution reaction(HER)due to its high intrinsic activity but suffering from thermodynamical instability.Although great efforts have been made to synthesize 1T-MoS_(2) and enhance its stability,it remains a big challenge to realize the phase control and stabilization of 1T-MoS_(2).Herein,based on crystal field theory analysis,we propose a new solution by designing an electrocatalyst of 1T-MoS_(2) nanosheets anchoring on black TiO2-xnanotube arrays in-situ grown on Ti plate(1T-MoS_(2)/TiO_(2-x)@Ti).The black TiO_(2-x)substrate is expected to play as electron donors to increase the charge in Mo 4 d orbits of 1T-MoS_(2) and thus weaken the asymmetric occupation of electrons in the Mo 4 d orbits.Experimental results demonstrate that black TiO_(2-x)nanotubes shift electrons to MoS_(2) and induce MoS_(2) to generate more 1 T phase due to stabilizing the 1T-MoS_(2) nanosheets compared with a Ti substrate.Thus 1T-MoS_(2/)TiO_(2-x)@Ti shows much improved HER performance with a small Tafel slope of 42 m V dec^(-1) and excellent catalytic stability with negligible degradation for 24 h.Theoretical calculations confirm that the black TiO_(2-x)substrate can effectively stabilize metastable 1T-MoS_(2) due to electrons transferring from black TiO_(2-x)to Mo 4 d orbits.This work sheds light on the instability of 1T-MoS_(2) and provides an essential method to stabilize and efficiently utilize 1T-MoS_(2) for HER.展开更多
Moderate anionic doping is an effective approach to improve the performance of electrocatalysts toward hydrogen evolution reaction(HER)since it can adjust the electronic structure,activesite,and phase.The reported stu...Moderate anionic doping is an effective approach to improve the performance of electrocatalysts toward hydrogen evolution reaction(HER)since it can adjust the electronic structure,activesite,and phase.The reported studies mainly focus on designing P doped C0S2,while otherphases of cobalt sulfide,such as Co1-xS and Co9S8 doped with P are rarely investigated for HER electrocatalysts.Herein,various cobalt sulfides(including CoSg/Co1-xS,Co1-xS,and Co9S8)doped with P are anchored on carbon cloth through a facile hydrothermal method.Among tested electrocatalysts,P doped Co1-xS exhibits excellent electrocatalytic performance with an overpotential of 110 and 165 mV(vs.RHE)for currentdensities of 10 and 100 mA·cm^-2,respectively.Density functional theory calculations reveal that P doped Co1-xS possesses a smaller bandgapand more optimal hydrogen adsorption sites than pristine Co1-xS.This work initially investigates various cobalt sulfides doped with P and furthergets in sight into the activity improvement mechanism of P dopi ng,which could guide the desig n of earth-abunda nt HER electrocatalysts for the"hydrogen economy".展开更多
基金supported by the New Zealand China Doctoral Research Scholarship (Grant no. 201706080124)support from the China Scholarships Council (CSC) for his study at the University of Auckland
文摘1T phase MoS_(2)(1T-MoS_(2)) is a promising substitute of platinum electrocatalyst for hydrogen evolution reaction(HER)due to its high intrinsic activity but suffering from thermodynamical instability.Although great efforts have been made to synthesize 1T-MoS_(2) and enhance its stability,it remains a big challenge to realize the phase control and stabilization of 1T-MoS_(2).Herein,based on crystal field theory analysis,we propose a new solution by designing an electrocatalyst of 1T-MoS_(2) nanosheets anchoring on black TiO2-xnanotube arrays in-situ grown on Ti plate(1T-MoS_(2)/TiO_(2-x)@Ti).The black TiO_(2-x)substrate is expected to play as electron donors to increase the charge in Mo 4 d orbits of 1T-MoS_(2) and thus weaken the asymmetric occupation of electrons in the Mo 4 d orbits.Experimental results demonstrate that black TiO_(2-x)nanotubes shift electrons to MoS_(2) and induce MoS_(2) to generate more 1 T phase due to stabilizing the 1T-MoS_(2) nanosheets compared with a Ti substrate.Thus 1T-MoS_(2/)TiO_(2-x)@Ti shows much improved HER performance with a small Tafel slope of 42 m V dec^(-1) and excellent catalytic stability with negligible degradation for 24 h.Theoretical calculations confirm that the black TiO_(2-x)substrate can effectively stabilize metastable 1T-MoS_(2) due to electrons transferring from black TiO_(2-x)to Mo 4 d orbits.This work sheds light on the instability of 1T-MoS_(2) and provides an essential method to stabilize and efficiently utilize 1T-MoS_(2) for HER.
基金This work was financially supported by the National Natural Science Foundation of China(No.21701153)National Postdoctoral Program for Innovative Talents(No.BX201700042).
文摘Moderate anionic doping is an effective approach to improve the performance of electrocatalysts toward hydrogen evolution reaction(HER)since it can adjust the electronic structure,activesite,and phase.The reported studies mainly focus on designing P doped C0S2,while otherphases of cobalt sulfide,such as Co1-xS and Co9S8 doped with P are rarely investigated for HER electrocatalysts.Herein,various cobalt sulfides(including CoSg/Co1-xS,Co1-xS,and Co9S8)doped with P are anchored on carbon cloth through a facile hydrothermal method.Among tested electrocatalysts,P doped Co1-xS exhibits excellent electrocatalytic performance with an overpotential of 110 and 165 mV(vs.RHE)for currentdensities of 10 and 100 mA·cm^-2,respectively.Density functional theory calculations reveal that P doped Co1-xS possesses a smaller bandgapand more optimal hydrogen adsorption sites than pristine Co1-xS.This work initially investigates various cobalt sulfides doped with P and furthergets in sight into the activity improvement mechanism of P dopi ng,which could guide the desig n of earth-abunda nt HER electrocatalysts for the"hydrogen economy".
