Enhancing durability and activity toward oxygen evolution reaction using single-site Re-doped NiFeO_x catalysts at ampere-level

NiFeO_x materials are known as among the most active catalysts toward oxygen evolution reaction (OER) for hydrogen generation in alkaline media. Nevertheless, the long-term durability of NiFeO_x catalysts for OER is still too far to the industrial application. Herein, we prepared a NiFeReO_x catalyst with single-site Re dopants and observed that the single-site Re dopants could significantly enhance the durability without compromising the activity. A cell voltage of 1.82 V without iR correction is noted at the current density of 3000 mA cm⁻² in anion-exchange membrane water electrolyzer (AEMWE) with NiFeReO_x catalyst, and a very small degradation is observed under 2000 and 1000 mA cm⁻², which remarkably outperforms the pristine NiFeO_x. Additionally, the overpotential of 305 mV at 10 mA cm⁻² is achieved with the NiFeReO_x catalyst, which is lower than 50 mV compared with the pristine NiFeOx catalyst, together with a smaller Tafel slope of 54.3 mV dec^-1. The boosted OER durability and activity of the NiFeReO_x catalyst could be attributed to the strong electron-withdrawing property of Re⁷⁺ single atoms leading to the electronic structure optimization and stabilization of Ni/Fe active sites. Our insights propose a new path for designing NiFeO_x catalysts with high durability and activity toward OER.