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

Multi-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).

Automated summary

Multi-metal electrocatalysts offer a wide range of catalytic possibilities through synergistic element interactions. This study presents a polymer/metal precursor spraying technique that enables the production of diverse multi-metal catalyst materials. The synthesized catalysts, including CoNiFeMoCr, were characterized and tested for the oxygen evolution reaction (OER). The CoNiFeMoCr catalyst exhibited a polycrystalline structure, and operando Raman measurements indicated the involvement of multiple active sites. Additionally, CoNiFeMoCr electrodes supported by Ni foam were utilized for water splitting in flow-through electrolysis cells and alkaline membrane electrode assembly (MEA) configurations, showing promising performance with high current densities.