Chromium Cation-induced Self-reconstruction of a Stable and High Performance Boride-derived Electrocatalyst for Oxygen Evolution Reaction

The judicious design of highly performing electrocatalysts for the oxygen evolution reaction (OER), holds the key to enhancing the overall electrolytic water splitting performance. Herein, we design highly efficient microenvironmentally-modified nickel sites by anion and cations (boron, chromium, and iron interaction) in the Cr-FeNiB electrocatalyst system to a stable OER catalyst via scalable one-pot synthesis. The systematic correlative electrochemical, structural, and chemical characterization reveals the formation of amorphous-crystalline core-shell structures, which transform into the activated nanosheet material with tailored intrinsic water oxidation catalytic activity. The enhanced water oxidation performance is attributed to the Cr-induced chemical self-reconstruction of the catalyst, which, as a result, provides better OER kinetics, boosted turnover frequency, and an optimum synergism effect of metal and boron constituents. The synergetic interplay of these factors impart the optimized Cr-FeNiB catalyst, with an impressive overpotential of 272 mV and 252 mV on a glassy carbon electrode and carbon fiber paper, respectively, to deliver the standard current density of 10 mA cm-2 in 1.0 M KOH. This contribution paves the way not only for a better understanding of metal boride-derived electrocatalysts but also contributes to future discoveries of non-noble metal catalysts that are highly efficient and stable.