A Scalable Strategy of "Ball-Milling-Assisted Laser Scanning Method" to Achieve Cr<sub>2</sub>Ni<sub>3</sub> Catalyst: An Unprecedented Robust Anode for Oxygen Evolution Reaction.

Abstract

Industrial water-alkali splitting is facing high energy consumption due to the high overpotential of commercial Ni mesh anode in oxygen evolution reaction (OER) processing. Herein, a simple ball-milling-assisted laser scanning strategy was employed to introduce the hardest Lewis acid chromium (Cr) into the Ni matrix to form Cr2Ni3 catalysts supported by Ni mesh, endowing such NiCr/Ni mesh anode a robust OER performance at a low-cost. It is shown that facilitating the self-adsorption of oxygen species and promoting the leaching of soluble Cr cations aids in reconstructing Ni cations into active (oxy)hydroxide species. This study explores the innovative development of Cr-doped NiCr/Ni mesh catalysts to create porous NiCr/Ni alloys with Cr2Ni3 as the active phase. The optimal Ni_0.5Cr_0.5-NM electrode demonstrates ultra-low overpotentials of 293 mV and 321 mV at 50 and 100 mA cm^-2, respectively, while maintaining excellent stability for over 100 hours at 100 mA cm^-2. This work provides insight into the batch fabrication of customized OER anodes for sustainable hydrogen production.