Oxygen-vacancy-rich TiO2 enables highly active and durable water electrolysis of urchin-like RuO2 catalyst

The material innovation is prerequisite to accelerating sluggish oxygen evolution reaction (OER) kinetics, thus promoting the realization of hydrogen energy community. Herein, we develop an oxygen-vacancy-rich TiO2 supported RuO2 catalyst (RuO2@r-TiO2) towards improved OER activity and stability. The oxygen vacancy on TiO2 not only supplies electrons to produce lower valence Ru, but also provides sufficient anchoring site for the deposition of RuO2 nanocrystal. Beyond that, it can generate strong electronic interaction between TiO2 and supported RuO2, and thereby tailors the intermediates’ adsorption energy on the RuO2 surface. As a result, the derived RuO2@r-TiO2 catalyst exhibits superior OER activity and stability with the overpotential of 211 mV at a current density of 10 mA cm−2 and negligible activity degradation after 6 h operation, outperforming the non-oxygen-vacancy counterpart (223.3 mV, 12.75% activity loss) and RuO2 catalyst (234.6 mV, 42.86% activity loss).