Mesoporous ruthenium titanium oxide solid solution with efficient three phase reaction interface for water electrolysis

The development of stable Ru-based anodes for acidic proton exchange membrane water electrolysis is promising, but strictly limited by Ru over-oxidation and structural collapse due to lattice oxygen participation under high current densities. Rational design of competitive Ru-based catalyst is, thereby, highly desired. Here, by exploring a customized self-assembly route, we report a type of mesoporous Ru-Ti-O solid solution catalyst delivering competitive performance (1 A cm -2 for over 450 h at 0.4mg Ru cm -2 ). Mechanistic investigations reveal that the enhanced performance arises from the integration of atomic-scale electronic structure tuning and mesoscopic triple phase interface engineering. The electron delocalization forms a conductive network and suppresses Ru overoxidation through electron donation. Atomically dispersed Ru-O-Ti motifs favor the oxygen pathway mechanism over the lattice oxygen mechanism, suppressing lattice oxygen release and enhancing structural stability. Simultaneously, the ordered mesoporous architecture and radially aligned nanorod bundles establish a robust, super-hydrophilic triple phase interface, enabling effective water and gas exchange and mitigating concentration overpotentials. This cross-scale design strategy offers a possible route to non-Ir catalysts with measurable activity and long-term durability for scalable acidic water electrolysis.