A Chalcogenide‐Derived NiFe2O4 as Highly Efficient and Stable Anode for Anion Exchange Membrane Water Electrolysis

Developing low‐cost, highly active, and durable oxygen evolution reaction (OER) electrodes is one of the critical scientific issues for anion exchange membrane water electrolyzer (AEM‐WE). Herein, we report a vacancy‐rich and alkali‐stable NiFe2O4‐type electrode (named as NiFeOx‐350‐Ov), derived from the chemical‐vapor deposited precursor NiFeSexSy‐350, as an efficient and robust anode material. The obtained electrode affords current densities of 100 and 500 mA cm−2 at overpotentials of 245 and 270 mV, respectively, and displays excellent long‐term durability sustaining 1.0 A cm−2 at least for 1000 h. When coupled with Ni4Mo/MoO2/NF as hydrogen evolution reaction (HER) catalyst, the resulting platinum group metal (PGM)‐free single‐cell AEM‐WE exhibits a cell voltage of 1.71 V at the current density of 1000 mA cm−2 at 80 °C and long‐term durability during a current‐cycling test between 0.5 and 1.0 A cm−2 over 150 h at 60 °C. This work highlights a unique reconstruction strategy for preparing highly active and durable OER catalysts used in PGM‐free AEM‐WE.