Lattice modulation strategy toward efficient and durable RuO2‐based catalysts for acidic water oxidation

Abstract Rutile RuO 2 is recognized for its outstanding acidic oxygen evolution reaction (OER) activity and notable cost advantage compared to iridium oxide for proton exchange membrane water electrolyzers (PEMWEs). However, the unsatisfactory stability of RuO 2 hinders its practical application. Here, we report a lattice modulation strategy to enhance both the OER activity and stability of RuO 2 . Interestingly, the newly synthesized Mo 0.15 Nb 0.05 ‐RuO 2 , with Mo doped first and then Nb, presents the greatest lattice spacing and possesses an overpotential of merely 205 mV at 10 mA cm −2 , which significantly outperforms Nb 0.05 Mo 0.15 ‐RuO 2 (239 mV), where Nb was doped first followed by Mo, as well as the initial RuO 2 (323 mV). Remarkably, Mo 0.15 Nb 0.05 ‐RuO 2 requires only 1.76 V to achieve 1 A cm −2 and exhibits exceptional stability in PEMWE testing, with a voltage rise of only 58 mV at 200 mA cm −2 for more than 80 h.