Molybdenum carbide supported metal-organic framework-derived Ni, Co phosphosulphide heterostructures as efficient OER and HER catalysts.

Molybdenum carbide (Mo C) has gained attention for water splitting due to its electronic structure resembling to Pt and have high electrochemical performance. We designed porous nanostructured phosphorus/sulfur co-doped Ni, Co phosphosulphide and molybdenum carbide heterostructures Mo C(MoC-MoC) through confined carburization within a metal-organic framework (MOF) matrix combined with a phosphosulfurization strategy. Starting from a carbon source consisting of NiCo-MOF incorporating molybdenum trioxide, we prepared MOF-derived NiCo-Mo C nanorods carbonization, which exhibited decent electrocatalytic performance for the hydrogen evolution reaction (HER) by electrochemical water splitting. The NiCo-Mo C showed low overpotentials of 153 mV and 157 mV RHE at a current density of 10 mA cm in 0.5 M HSO and 1 M KOH, respectively. Phosphosulfurization of NiCo-Mo C, performed under controlled conditions, resulted in the formation of NiPS-CoPS-Mo C, which demonstrated superior HER performance than the precursor NiCo-Mo C with overpotentials of 75.2 mV and 86.6 mV in 0.5 M HSO and 1 M KOH, respectively and an overpotential of 184.5 mV at 10 mA cm for the oxygen evolution reaction (OER). The durability of the NCMCSP-based electrolyzer for the overall water splitting was evaluated by measuring the voltage over time at a constant current density of 20 mA cm for 12 h.