Fe(Ni)Se2/Se nanoparticles anchored on C3N4 as highly active electrocatalysts in oxygen evolution reaction and liquid Zn-air batteries

Finding catalysts with a high concentration of active sites and superior intrinsic activity is critical in boosting electrocatalytic efficiency. In this paper, Fe(Ni)Se₂/Se-C₃N₄ is prepared through a hydrothermal and subsequent selenization method. The prepared Fe(Ni)Se₂/Se-C₃N₄ catalyst exhibits outstanding OER performance, with a 225 mV overpotential at a current density of 10 mA cm⁻². It also shows strong catalytic stability. After 856 h of testing at a current density of 2 mA cm⁻², there is comparatively little current deterioration. The zinc-air battery assembled using Fe(Ni)Se₂/Se-C₃N₄ as the catalyst shows a maximum specific capacity of 699.0 mAh g⁻¹. At a current density of 273.1 mA cm⁻², the power density increases to a maximum of 157.1 mW cm⁻². The internal electron transport between Fe(Ni)Se₂/Se and C₃N₄ modulates the electronic structure and subsequently enhances the catalytic performance, as demonstrated by synchronized radiation and theoretical calculations. The catalyst’s large specific surface area and abundance of active sites contribute to the improvement of catalytic activity. This work provides useful recommendations for the synthesis and design of efficient bifunctional catalysts in the future, facilitating the commercialization of electrocatalysis.