Interfacial Ru centers coupling with oxygen vacancies in VO-RuO2@CA hybrid aerogel boosts acidic water oxidation

Abstract

The exploitation of highly active, cheap cost and durable electrocatalyst for acidic water oxidation reaction still presents a major technological and scientific challenge in proton exchange membrane water electrolysers (PEMWEs). Herein, a hybrid aerogel of oxygen defect-rich RuO2 nanoparticles coupling with carbon (VO-RuO2@CA) was designed to promote their activity and stability during acid water oxidation. The optimized VO-RuO2@CA achieves an ultralow overpotential of 207 mV at 10 mA cm−2 for acidic water oxidation and sustains a prominent long-term stability during the 30 h chronopotentiometry test in 0.5 M H2SO4. Furthermore, VO-RuO2@CA exhibits high mass activities of 186.5 mA mgRu−1 and TOF values of up to 2.07 s−1 at an overpotential of 300 mV, being 17.7 and 4.8 times higher than commercial RuO2, respectively. Theory calculations and experimental results verify that the oxygen vacancies (VO) could significantly weaken the binding energy of O* with respect to OOH* for the interfacial Ru centers between RuO2 and carbon, rendering the increase of the intrinsic water oxidation activity and resistance to over-oxidation for RuO2. This research provides a novel pathway to explore remarkably efficient 3D porous hybrid aerogel electrocatalysts toward anodic electrocatalysts applications in PEMWEs.