Electronic Modulation of RuCo Catalysts on TiO₂ Nanotubes Promoting Durable Acidic Overall Water Splitting

Abstract The development of efficient and durable bifunctional electrocatalysts is essential for hydrogen production from acidic water splitting. Herein, a TiO 2 nanotube‐loaded Co‐doped Ru nanoparticle catalyst (RuCo/TiO 2 NTs) is reported that exhibits excellent activity and stability toward acidic oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). The Ru─O─Ti bonding is enhanced by Co doping, and the metal carrier interaction between Ru nanoparticles and TiO 2 NTs is enhanced, which effectively stabilizes Ru species during OER and initiates hydrogen spillover accelerating HER kinetics. As a result, RuCo/TiO 2 NTs catalyst requires only 156 mV OER overpotential and 17 mV HER overpotential to achieve a current density of 10 mA cm −2 with a stability more than 500 h in acidic conditions. More importantly, benefiting from the excellent bifunctional activities, the proton exchange membrane electrolyte assembled from RuCo/TiO 2 NTs has excellent activity and robust stability (1000 h). This work opens a new avenue for the efficient energy conversion devices.