Oxygen vacancy induced construction of NiCo2O4/NiSe2 heterostructure electrocatalyst for high-efficiency oxygen evolution reaction

Spinel-type transition metal oxide (AB₂O₄) are promising non-precious metal catalysts for oxygen evolution reaction (OER), addressing the challenges of high cost and poor stability in electrocatalytic water splitting. However, their widespread application is hindered by low electrical conductivity and suboptimal performance. In this study, we developed an oxygen vacancy anchoring strategy to construct a highly efficient and durable NiCo₂O₄-NiSe₂ heterojunction catalyst on a nickel foam substrate. The three-dimensional cross-linked porous nanorod array facilitates mass and charge transportation. The abundant interconnected interfaces enhance electron transfer kinetics and adsorption of OH intermediates, as confirmed by theoretical simulations. As a result, the as-synthesized NiCo₂O₄@NiSe₂/NF exhibits an overpotential of only 299 mV at a current density of 60 mA cm^-2, significantly outperforming the single-phase NiCo₂O₄ and demonstrating exceptional durability.