High-Performance Electrocatalysts for Anion-Exchange Membrane Electrolyzers through Acoustic Cavitation

Electrochemical water splitting is a promising technology for the sustainable production of green hydrogen. Large-scale hydrogen production demands efficient electrocatalysts to continuously operate at large current densities. Catalyst deterioration and its peel-off are major concerns at large current densities, resulting in subpar performance. Herein, we utilized acoustic cavitation-assisted electrodeposition to synthesize highly efficient and robust NiFe and NiMn oxyhydroxide catalysts for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), respectively. The acoustic cavitation process led to the development of a uniform nanoscale structure, partial amorphization, and the formation of oxygen vacancies, likely as a result of high-strain deformation. The synthesized catalysts demonstrated excellent performance, with very low overpotentials of 285 and 189 mV at 1000 mA/cm², for OER and HER respectively. The cell configuration required 1.76 V only for achieving 1 A/cm² and demonstrated negligible deterioration after 24 h of continuous operation. The commercial viability of the developed catalysts was obtained by testing in a 2.5 × 2.5 cm² anion-exchange membrane (AEM) stack up to a 1.2 A/cm² current density. The potentials required to reach industry-relevant high current densities of 500 and 1000 mA/cm² were 2.1 and 2.6 V, respectively. The electrode stability at the electrolyzer scale was investigated by running the stack at current densities from 100 to 1000 mA/cm² for a total of 100 h, wherein the electrode demonstrated high durability and robustness.