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

Abstract

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 TiO 2 nanosheets were prepared by a two-step hydrothermal method and calcination in two different atmospheres (H 2 /Air) to obtain two types of RuNi− TiO 2 /Ti and Ru(Ni)O 2 −TiO 2 /Ti nanosheets. The TiO 2 nanosheets with large specific surface area are beneficial for dispersing nanoscale RuNi species. Furthermore, the RuNi catalyst firmly binds with the TiO 2 nanosheets and enhances the electrochemical stability. Accordingly, the constructed Ru(Ni)O 2 −TiO 2 /Ti∥Ru-Ni−TiO 2 /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 TiO 2 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.