Cobalt single-atom-decorated nickel thiophosphate nanosheets for overall water splitting

Abstract

Formidable challenges in the development of efficient single-atom catalysts including accessible fabrication processes, unambiguous interactions with matrixes, and accelerated kinetics of catalytic mechanisms, pose an obstacle in maximizing the catalytic performance. Herein, it is proposed, for the first time, to bond single-atom Co on the surface of single-layered nickel thiophosphate (SA Co NiPS₃) forming a uniform unsaturated coordination mode of isolated Co. Theoretical studies indicate that the SA Co NiPS₃ electrode possesses a higher intrinsic activity than that of traditional Co alternative-doped NiPS₃via the enhancement of conductivity and the reduction of energy barriers for bifunctional hydrogen/oxygen evolution reactions (HERs/OERs). Notably, a water splitting electrolyzer assembled using SA Co NiPS₃ nanosheets as both the cathode and the anode achieves 50 mA cm⁻² at 1.60 V, which outperforms the Pt/C//RuO₂ benchmark (1.74 V@50 mA cm⁻²). Besides, this electrocatalyst exhibits an outstanding durability up to 6 days with negligible decay. This work shines fresh light on igniting 2D metal thiophosphate electrocatalytic activity that even surpasses noble-metal-based electrocatalysts via the single-atom engineering.