Efficient Bifunctional V-Doped NiCoP/Ni₂P Electrocatalysts for Overall Water Splitting via a Simple Heterointerface Construction Strategy

Developing efficient bifunctional electrocatalyst with oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is imperative for water electrolysis. Herein, the construction of heterointerfaces was achieved through the simple phosphating treatment, and a unique chrysanthemum-like V-doped NiCoP/Ni₂P/NF was synthesized for the efficient water splitting. The prepared V-doped NiCoP/Ni₂P/NF demonstrated favorable bifunctional catalytic performance, requiring low overpotentials of 82 mV and 245 mV to achieve current densities of 10 mA cm⁻² for the HER and OER, respectively. At a current density of 50 mA cm⁻², the cell voltage for overall water splitting (OWS) is only 1.66 V, with no significant degradation after 60 h of operation. The characterization and DFT calculations revealed that the heterointerfaces between NiCoP and Ni₂P significantly enhanced the catalytic performance by facilitating electron transfer and optimizing charge distribution. Vanadium doping further changed the electronic properties at the interfaces and optimized the adsorption of intermediates. Due to the synergistic effect of heterointerfaces and vanadium doping, V-doped NiCoP/Ni₂P/NF exhibited excellent bifunctional properties, with more reaction sites, high conductivity, and stability. This strategy could open up new possibilities for designing high performance catalysts for renewable energy production and sustainable hydrogen generation.