A Cost‐Effective 3D Hydrogen Evolution Cathode with High Catalytic Activity: FeP Nanowire Array as the Active Phase

Abstract Iron is the cheapest and one of the most abundant transition metals. Natural [FeFe]‐hydrogenases exhibit remarkably high activity in hydrogen evolution, but they suffer from high oxygen sensitivity and difficulty in scale‐up. Herein, an FeP nanowire array was developed on Ti plate (FeP NA/Ti) from its β‐FeOOH NA/Ti precursor through a low‐temperature phosphidation reaction. When applied as self‐supported 3D hydrogen evolution cathode, the FeP NA/Ti electrode shows exceptionally high catalytic activity and good durability, and it only requires overpotentials of 55 and 127 mV to afford current densities of 10 and 100 mA cm 2 , respectively. The excellent electrocatalytic performance is promising for applications as non‐noble‐metal HER catalyst with a high performance–price ratio in electrochemical water splitting for large‐scale hydrogen fuel production.