摘要
Remote hydrogen plasma was used to create sulfur vacancies on amorphous molybdenum sulfide, which leads to significant enhancement in their HER performance. A-MoS x on carbon cloth (CC) was prepared by the thermolysis of ammonium thiomolybdate ((NH 4 ) 2 MoS 4 ) at 150°C in an H 2 /Ar environment. To evaluate the atomic ratio of a-MoS x , X-ray photoelectron spectroscopy (XPS) is adopted to characterize the surface bonding structures and estimate the amount of sulfur vacancies. To reveal the catalytic properties of pristine- and sulfur-deficient MoS x , first-principles calculations of the hydrogen-adsorption free energy difference for the HER reaction was performed on the pristine basal plane and the sulfur vacancy sites. The hydrogen plasma is a scalable way to create defects but without damaging the structure. The overpotential of a-MoS x is decreased from 206 to 143 mV after plasma treatment due to the increase in active site density. The measurements in PEM-based electrolyzer also prove that the a-MoS x exhibits superior performance than Pt. It is believed that the hydrophilic amorphous molybdenum sulfide is a cheap alternative, which exhibits superior catalytic and stability performance than Pt at high current densities.