Durable acidic water oxidation ruthenium based electrocatalyst by fluorination induced symmetry breaking

Ru–based materials exhibit high electrocatalytic activity for the acidic oxygen evolution reaction, but they are prone to transform into soluble RuO4 species via traditional lattice oxygen mechanism at high oxidation potentials, resulting in rapid inactivation. Herein, density functional theory calculations predict that the F induced symmetry–breaking can alter the oxygen evolution reaction route of RuO2 from the lattice oxygen mechanism route to the stable adsorption evolution mechanism pathway. Consequently, we fabricate an efficient F–RuO2/FC electrocatalyst by substituting a portion of O in RuO2 with F. Specifically, it can operate continuously for over 1440 h (2 months) at 100, 500 and 1000 mA cm–2 when using F–RuO2/FC as anode electrocatalyst in proton exchange membrane water electrolyzer. Detailed in situ experiments demonstrate that the adsorption of intermediates is impacted by the presence of F in RuO2, thus forcing the oxygen evolution reaction to proceed via the adsorption evolution mechanism. This study provides experimental and theoretical insights for customizing stable Ru–based electrocatalysts for water splitting and beyond. Maintaining the stability of Ru–based materials in the acidic oxygen evolution reaction remains a challenge. Here, the authors report a fluorination–induced symmetry–breaking strategy that enhances the structural stability of RuO2, enabling over 1,440 h of continuous operation at 100–1000 mA cm⁻².