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.