Al-Induced In Situ Formation of Highly Active Nanostructured Water-Oxidation Electrocatalyst Based on Ni-Phosphide

We report a simple low-cost concept for the preparation of water-oxidation electrocatalyst via modification of self-supported Ni5P4–Ni2P foam catalyst precursor with Al. As an anode for alkaline oxygen evolution reaction, this material exhibits an impressive Tafel slope of 27 mV dec–1 and offers anodic current densities of 10, 100, and 300 mA cm–2 at overpotentials of merely 180, 247, and 312 mV, respectively. Moreover, the anode demonstrates high operational stability, as reflected by a steady-state performance for more than 8 days. Combining state-of-the-art electron microscopy and photoelectron spectroscopy, we investigated the role of the Al dopant in the formation of active Ni(OH)2/NiO/Ni5P4–Ni2P nanocatalyst, which exhibits oxygen-evolving activity among the highest reported to date.