MOF-derived in situ carbon-coated NiCoP/Ti3C2Tx with interfacial coupling for high-performance overall water splitting

Developing efficient bifunctional electrocatalysts capable of facilitating water splitting to produce hydrogen and oxygen remains a significant challenge. This study presents a controllable conversion of MOFs to carbon-coated NiCoP nanostructures via low-temperature phosphidation using a NiCo-MOF/Ti 3 C 2 T x precursor, leading to the construction of the NiCoP@C/Ti 3 C 2 T x bifunctional electrocatalyst. Characterization of the synthesized NiCoP@C/Ti 3 C 2 T x composite material and electrochemical testing revealed that the material exhibits high catalytic activity in both HER and OER. At a current density of 10   mA   cm −2 , the overpotential for HER is measured at 58   mV with a Tafel slope of 60   mV dec −1 , while the overpotential for OER is found to be 240   mV, with a Tafel slope of 42   mV dec −1 . The potential required to achieve a current density of 10   mA   cm −2 for overall water splitting is 1.53   V, which is lower than commercial Pt/C and RuO 2 electrocatalysts. Additionally, the material demonstrates excellent electrocatalytic performance at higher current densities. The outstanding electrocatalytic performance is attributed to the effective stabilizing effect of the carbon-coated layer on the high-activity NiCoP particles, thereby suppressing the loss of active sites during the reaction. Moreover, the strong interfacial coupling effect between NiCoP and Ti 3 C 2 T x significantly enhances the interfacial charge transfer kinetics, consequently improving catalytic efficiency.