Metal/Metal Oxide Modulation of RuNi Catalysts on TiO2 Nanosheets Promoting Overall Water Splitting

Electrochemical water splitting into hydrogen is deemed as an efficient approach for storing and utilizing renewable clean energy. Designing low-cost and efficient catalysts is crucial for the large-scale production of hydrogen from water splitting. Herein, Ni-doped Ru catalysts supported on the TiO2 nanosheets were prepared by a two-step hydrothermal method and calcination in two different atmospheres (H2/Air) to obtain two types of RuNi–TiO2/Ti and Ru(Ni)O2–TiO2/Ti nanosheets. The TiO2 nanosheets with large specific surface area are beneficial for dispersing nanoscale RuNi species. Furthermore, the RuNi catalyst firmly binds with the TiO2 nanosheets and enhances the electrochemical stability. Accordingly, the constructed Ru(Ni)O2–TiO2/Ti∥RuNi–TiO2/Ti exhibits superior oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) performance. Such excellent performance could be ascribed to the rich specific surface area of TiO2 nanosheets, the synergistic effect between Ru and Ni, and their strong metal–support interaction (SMSI), which regulates the electronic structure of the active sites and increases the electrochemically active area, thus promoting their catalytic performance during overall water splitting.