Scalable Synthesis of Multi‐Metal Electrocatalyst Powders and Electrodes and their Application for Oxygen Evolution and Water Splitting

Abstract

AbstractMulti‐metal electrocatalysts provide nearly unlimited catalytic possibilities arising from synergistic element interactions. We propose a polymer/metal precursor spraying technique that can easily be adapted to produce a large variety of compositional different multi‐metal catalyst materials. To demonstrate this, 11 catalysts were synthesized, characterized, and investigated for the oxygen evolution reaction (OER). Further investigation of the most active OER catalyst, namely CoNiFeMoCr, revealed a polycrystalline structure, and operando Raman measurements indicate that multiple active sites are participating in the reaction. Moreover, Ni foam‐supported CoNiFeMoCr electrodes were developed and applied for water splitting in flow‐through electrolysis cells with electrolyte gaps and in zero‐gap membrane electrode assembly (MEA) configurations. The proposed alkaline MEA‐type electrolyzers reached up to 3 A cm−2, and 24 h measurements demonstrated no loss of current density of 1 A cm−2.