Exploring the electrocatalytic prowess of a synergistic 1T-MoS2-metallic Ni composite towards alkaline hydrogen evolution

Abstract

Designing of suitable electrocatalysts for efficient alkaline hydrogen evolution reaction (HER) is a challenging task owing to the additional energy consumption to disintegrate the H–OH bond in the Volmer step. Under these circumstances, strong synergistic interactions between Ni/Co derivatives with 1T-MoS₂ can frequently accelerate the alkaline HER. This study addresses the challenge of designing efficient electrocatalysts for the alkaline HER, focusing on minimizing additional energy consumption during the Volmer step. A composite structure, 1T-MoS₂–Ni(18), was synthesized using 1T-MoS₂ and metallic Ni for effective alkaline HER catalysis. Rigorous physical characterization confirmed the formation of an interfacial structure between 1T-MoS₂ and metallic Ni. The resulting composite exhibited very good alkaline HER performance, requiring only a 120 mV overpotential for a standard 10 mA cm⁻²_geo current density. The improved performance was attributed to feasible water dissociation over the metallic Ni promoter, facile electron migration kinetics through the interfacial structure, and enhanced per-site activity. In addition, for the practical execution of an alkaline electrolyzer, NiS nanoparticles were synthesized as an OER catalyst, exhibiting only a 310 mV overpotential (1.54 V vs. RHE) to attain a 10 mA cm⁻²_geo current density. The alkaline electrolyzer, (NiS (+)||1T-MoS₂–Ni(18) (−)), delivered a 1.68 V cell potential to sustain a 10 mA cm⁻²_geo current density with excellent stability for up to 48 h.