3D mesoporous rose-like nickel-iron selenide microspheres as advanced electrocatalysts for the oxygen evolution reaction

The development of efficient and stable non-noble metal-based electrocatalysts for the oxygen evolution reaction (OER) is one of the essential challenges for the upcoming hydrogen economy. Herein, 3D mesoporous nickel iron selenide with rose-like microsphere architecture was directly grown on Ni foam via a successive two-step hydrothermal method. The unique 3D mesoporous rose-like morphology leads to a higher number of active sites as well as fast mass and electron transport through the entire electrode, and facilitates the release of O₂ bubbles formed during the OER catalysis. As a result, the synthesized Ni_0.76Fe_0.24Se exhibits superior OER performances, with an ultralow overpotential of 197 mV needed to produce a current density of 10 mA·cm^–2 in 1 M KOH, outperforming all transition metal selenide OER catalysts reported to date.