MXene-MOF architectural hybrid-supported nickel single-atom catalysts for hydrogen evolution reactions

Single-atom catalysts (SACs) are becoming high-performance materials with efficient catalytic potential toward heterogenous catalysis. In this view, synthesizing SACs via strong interaction with a support matrix is a crucial step. MXenes are the most frequently used two-dimensional support matrices; however, the hybridization of MXene-MOF toward catalysis is less explored. Herein, we report the fabrication of architectural arrangement of MXene-MOF to support nickel single atoms using a pyrolysis strategy. Here, the Ti vacancy sites are loaded with Ni atoms. Morphological SEM and Cs-STEM analyses confirmed the bridge-like arrangement of FE-MOFs between MXene sheets with immobilized Ni SACs. The local coordination of immobilized Ni SACs on the MXene surface was further characterized by X-ray absorption spectroscopy (XAS). The constructed MXene-MOF hybrid-supported Ni SACs (MFN) exhibited effective catalytic activity with a low over potential of 52 mV at 10 mA cm⁻². Density functional theory calculations revealed that the interaction of isolated Ni atoms with C, together with iron oxide bonded on MXene supports, singnificantly optimized the electronic density of states, thereby enhancing the catalytic activity. The observations of this study would motivate further research to evaluate MXene-MOF-SAC hybrid catalyst materials for energy applications.