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.