Mo Doped Amorphous CoSx Porous Leaf-Like Nanostructure on Ti Mesh as Electrocatalyst for Alkaline Hydrogen Production

Abstract

Reducing water dissociation barrier and then expediting its kinetics are of great significance to enhance alkaline water splitting for hydrogen evolution. Herein, Mo doped CoSx on Ti mesh (defined as Mo doped CoSx/TM) was synthesized by multistep pathways using Co-MOF as precursor. The characterization results confirmed the amorphous structure and porous leaf-like morphology of Mo doped CoSx. The alkaline HER measurement indicated Mo doped CoSx/TM exhibited the enhanced HER performance with overpotential (η) of 230 mV at −10 mA cm−2, lower than that of Co3S4/TM (265 mV) and other samples (>350 mV), and reduced Tafel slope (98.3 mV dec−1), as well as decent stability. The lowest Tafel slope meant the highest water dissociation kinetics and the reaction followed Volmer-Heyrovsky mechanism over Mo doped CoSx/TM. The excellent alkaline HER performance of Mo doped CoSx/TM was due to the increased intrinsic activity caused by cooperative effect between Mo and CoSx, and the porous leaf-like structure, which was in favor of exposing much more accessible active sites and facilitating mass transfer. This work demonstrates the validity of Mo doping in promoting HER performance of cobalt sulfide, which offers a strategy to design highly efficient transition metal chalcogenides for catalysis and energy conversion.