A simple postsynthetic in-situ cation exchange strategy to construct Fe-doped Ni3Se4 nanoarray for enhanced oxygen evolution reaction

For industrial high-purity green hydrogen production, it is necessary to develop efficient, economical and stable non-precious metal-based alkaline media oxygen evolution reaction (OER) electrocatalysts. In this study, a simple stepwise synthesis strategy was proposed to construct a hierarchical MOF-based Prussian blue analogue by Ni-BPDC and derived from it to grow Fe-doped Ni3Se4 in situ on nickel foam (Fe-Ni3Se4/NF) as an efficient and stable alkaline OER electrocatalyst. Fe doping enables better modulation of the electronic structure of Ni3Se4 and increases the number of active sites and electrochemical surface area to improve the OER activity. Fe-Ni3Se4/NF exhibits remarkable electrocatalytic performance in 1 M KOH with low overpotential (211 mV at 10 mA cm−2) and small Tafel slope (34.44 mV dec−1), which is superior to that of commercial RuO2 catalysts. Its electrochemical characteristics are stable at 10 mA cm−2 for more than 24 h, making it a viable non-precious metal-based electrocatalyst for alkaline OER. This synthetic approach could open up new possibilities for the fabrication of MOF-based hierarchical Prussian blue analogs as well as derivatives to be oriented for applications in various fields.