Awakening Solar Hydrogen Evolution of MoS 2 in Alkalescent Electrolyte through Doping with Co

Transition metal dichalcogenides, especially MoS 2 , 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 MoS 2 is profoundly restricted by acidic media. Co‐doped MoS 2 (Co‐MoS 2 ) nanosheets are found to enable the highly efficient solar H 2 evolution of CdS nanowires (NWs) in alkalescent electrolyte. The content of Co in MoS 2 is optimized to 2.8 % and the Co‐MoS 2 content in Co‐MoS 2 /CdS NWs hybrids is 2.5 wt %; the optimized Co‐MoS 2 /CdS NWs shows a high H 2 evolution rate of 14.22 mmol g −1  h −1 and 71 % apparent quantum efficiency in the Na 2 SO 3 electrolyte. Moreover, the H 2 generation enabled by the Co‐MoS 2 cocatalyst can exhibit universality in alkalescent electrolytes, such as triethanolamine (TEA) and disodium ethylenediaminetetraacetic acid (EDTA), exhibiting greater photocatalytic H 2 generation than Pt/CdS. The design of Co‐MoS 2 /CdS sheds light on the development of highly efficient low‐cost photocatalysts for solar H 2 generation from water reduction.