Activation Strategy of WS_2 as an Efficient Photocatalytic Hydrogen Evolution Cocatalyst through Co~(2+) Doping to Adjust the Highly Exposed Active (100) Facet

摘要

As an effective method to improve the surface catalytic activity of catalysts, crystalplane engineering has become a research hot spot in recent years. Dopingregulation of the highly exposed facet with low surface energy is helpful to expandtheir applications in the field of photocatalysis. Therefore, low concentrationtransition metal ions (Co~(2+)) in the high exposure surface (100) of WS_2 by one-pothydrothermal method are doped. Moreover, density functional theory (DFT)calculation shows that after Co~(2+) in WS_2 (100) crystal replaces W~(4+), the surfacecharge is rearranged, and the local charge near Co~(2+) is enhanced, whichaccelerates the electron transfer rate, makes the electron transfer rapidly to (100)facet through the secondary transfer process, and finally promotes protonreduction. Therefore, the hydrogen production efficiency of 7% (Co–WS_2)/Cd_(0.4)Zn_(0.6)S (CZS) Schottky junction (21 000 μmol g~(-1) h~(-1)) is 9.3 times and1.3 times higher than that of CZS (2265 μmol g1 h~(-1)) and 7% WS_2/CZSheterojunction (17 000 μmol g~(-1) h~(-1)). This study has certain reference andguiding significance for the study of new cocatalysts, not only on pristine semiconductorbut also for semiconductor-based hybrid structures.