Isolated Ni-atom catalyst supported on Ti3C2Tx with an asymmetrical C–Ni–N structure for the hydrogen evolution reaction

Abstract

Single-atom catalysts (SACs), distinguished by their exceptional atomic efficiency and modifiable coordination structures, find wide-ranging applicability, notably in the context of the hydrogen evolution reaction (HER). Herein, we synthesized a Ti₃C₂T_x-based Ni single-atom catalyst (Ni SA@N-Ti₃C₂T_x) by immersing a single Ni atom into the Ti vacancies of Ti₃C₂T_x and using a N-doping strategy. X-Ray adsorption fine structure revealed the formation of local Ni-N₁C₁ and an unsaturated C–Ni–N bridge configuration for isolated Ni species. Moreover, Ni SA@N-Ti₃C₂T_x exhibited an excellent HER performance with an overpotential of 63 mV at 10 mV cm⁻². This work could enable use of MXene-based SACs in the HER.