Heterojunctions of cobalt-nickel base selenides for high efficiency oxygen evolution reaction at high current density

Developing low-cost, high efficient, and durable non-precious metal electrocatalysts for is for the oxygen evolution reaction (OER) is pivotal for advancing sustainable water electrolysis toward commercial hydrogen production. Herein, CoSe₂@NiSe₂/NF heterostructured electrocatalysts were prepared on three-dimensional nickel foam (NF) substrate by facile solution selenization combined with hydrothermal method. The as-prepared catalyst with heterostructure and interconnected flake-like structures optimizes OH⁻ intermediate adsorption and accelerates charge transfer at the CoSe₂/NiSe₂ interfaces, exposes abundant active sites to facilitate mass transport and electrochemical reactions, then boosts the OER performance. Electrochemical measurements demonstrate that the CoSe₂@NiSe₂/NF-2 catalyst exhibits an overpotential of 229 mV, a Tafel slope of 43.1 mV/dec, and stable operation for 100 h at 10 mA/cm². Notably, it maintains exceptional durability under industrial-relevant conditions, sustaining stable performance for 400 h at a high current density of 1 A/cm². This work provides a new idea for constructing heterostructured electrocatalysts with optimized electronic structures and robust stability, offering promising insights for the design of high-performance OER catalysts toward practical water-splitting applications.