Atomic bridging modulation of Ir–N, S co-doped MXene for accelerating hydrogen evolution

Abstract

Two-dimensional Ti₃C₂T_x MXenes have attracted significant interest as low-cost supports to anchor single atoms owing to their unique properties. Nevertheless, there is still a lack of systematic investigation on the coordinative interaction between single atoms and functionalized MXene. Herein, we construct a novel catalyst consisting of Ir single atoms confined in porous heteroatom (N, S) co-doped Ti₃C2T_x. XAS demonstrates the in situ formation of a new bridging structure of Ir atoms with N and S atoms, which enables good dispersion of Ir atoms among the porous N, S-doped Ti₃C₂T_x. The optimal Ir_SA-2NS-Ti₃C₂T_x shows remarkable catalytic activity towards the HER in acidic and basic electrolytes. DFT calculations reveal that the N, S co-doped Ti₃C₂T_x support can capture electrons from Ir single atoms, resulting in charge redistribution in the interfacial region of the Ti₃C₂T_x support, thereby realizing enhanced HER activity. This work demonstrates a new strategy to modulate the atomic bridging status of the atomically dispersed active sites for improving electrocatalysis.