Rational design of Ru aerogel and RuCo aerogels with abundant oxygen vacancies for hydrogen evolution reaction, oxygen evolution reaction, and overall water splitting

Developing efficient, robust, and cost-effective catalysts to boost the electrocatalytic properties of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) for overall water splitting is fundamentally important yet very challenging. Herein, we report a facile method to prepare Ru-based aerogels for HER, OER, and water electrolysis . Specifically, Ru aerogel exhibits comparable HER performance with Pt/C, evidenced by a close overpotential at 10 mA cm −2 , a smaller Tafel slope, and an outperformed long-term stability. Among a series of RuCo aerogels, the Ru 0.7 Co 0.3 aerogel has the best OER performance superior to the RuO 2 benchmark catalyst, with a very small overpotential of 272 mV at 10 mA cm −2 , a low Tafel slope value of 41.6 mV dec −1 , and the improved long-term durability. The excellent OER performance of the Ru 0.7 Co 0.3 aerogel is mainly attributed to the RuCo synergistic catalytic effect, the abundant oxygen vacancies , and the structural merits of the sample. Notably, in the practical overall water splitting test, the combined Ru and Ru 0.7 Co 0.3 aerogel catalyst outperforms the Pt/C + RuO 2 couple. This study can shed light on preparation of metal aerogel-based bifunctional electrocatalyst for overall water splitting and beyond.