Awakening Solar Hydrogen Evolution of MoS2 in Alkalescent Electrolyte through Doping with Co.

Abstract

Transition metal dichalcogenides, especially MoS2 , have been regarded as promising cocatalysts for the hydrogen evolution reaction (HER) because of a near-zero Gibbs free energy for H+ absorption. However, the HER activity of MoS2 is profoundly restricted by acidic media. Co-doped MoS2 (Co-MoS2 ) nanosheets are found to enable the highly efficient solar H2 evolution of CdS nanowires (NWs) in alkalescent electrolyte. The content of Co in MoS2 is optimized to 2.8 % and the Co-MoS2 content in Co-MoS2 /CdS NWs hybrids is 2.5 wt %; the optimized Co-MoS2 /CdS NWs shows a high H2 evolution rate of 14.22 mmol g-1 h-1 and 71 % apparent quantum efficiency in the Na2 SO3 electrolyte. Moreover, the H2 generation enabled by the Co-MoS2 cocatalyst can exhibit universality in alkalescent electrolytes, such as triethanolamine (TEA) and disodium ethylenediaminetetraacetic acid (EDTA), exhibiting greater photocatalytic H2 generation than Pt/CdS. The design of Co-MoS2 /CdS sheds light on the development of highly efficient low-cost photocatalysts for solar H2 generation from water reduction.