Activity-Stability Balance: The Role of Electron Supply Effect of Support in Acidic Oxygen Evolution

Developing efficient and durable electrocatalysts for the oxygen evolution reaction (OER) in proton exchange membrane (PEM) electrolyzers represents a significant challenge. Herein, the cobalt-ruthenium oxide nano-heterostructures are successfully synthesized on carbon cloth (CoOx/RuOx-CC) for acidic OER through a simple and fast solution combustion strategy. The rapid oxidation process endows CoOx/RuOx-CC with abundant interfacial sites and defect structures, which enhances the number of active sites and the charge transfer at the electrolyte-catalyst interface, promoting the OER kinetics. Moreover, the electron supply effect of the CoOx support allows electrons to transfer from Co to Ru sites during the OER process, which is beneficial to alleviate the ion leaching and over-oxidation of Ru sites, improving the catalyst activity and stability. As a self-supported electrocatalyst, CoOx/RuOx-CC displays an ultralow overpotential of 180 mV at 10 mA cm(-2) for OER. Notably, the PEM electrolyzer using CoOx/RuOx-CC as the anode can be operated at 100 mA cm(-2) stably for 100 h. Mechanistic analysis shows that the strong catalyst-support interaction is beneficial to redistribute the electronic structure of Ru-O bond to weaken its covalency, thereby optimizing the binding energy of OER intermediates and lowering the reaction energy barrier.

Automated summary

Efficient and durable cobalt-ruthenium oxide nano-heterostructures (CoOx/RuOx-CC) are successfully synthesized on carbon cloth using a rapid solution combustion strategy for acidic oxygen evolution reaction (OER). The unique structure and electron transfer properties of CoOx/RuOx-CC enhance the OER kinetics, improve the catalyst stability, and exhibit an ultralow overpotential of 180 mV at 10 mA cm(-2) for OER. The mechanism analysis reveals that the strong catalyst-support interaction optimizes the binding energy of OER intermediates by redistributing the electronic structure of Ru-O bond.