Water Electrolysis Application of Atomically Dispersed Metallic Materials

Water electrolysis is one of the sustainable strategies to produce green hydrogen using renewable energies. The electrocatalysts used in water electrolysis play a critical role in increasing the energy efficiency of the process. Therefore, developing high-efficient catalysts to decrease the energy consumption and accelerate the water-splitting processes such as the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) is necessary. Among different types of catalysts, single-atom catalysts (SACs) have shown great advantages to enhance the kinetics of both the HER at the cathode and the OER at the anode. The SAC catalysts employed in water electrolysis devices are mainly noble metals and transition metals supported by the supporting materials. The supports of SACs have strong influences on the geometric structure, loading, coordination environment, and charge transfer of the single-metal atoms, which enable the high activity, selectivity, efficiency, and stability of SACs. This chapter summarizes the progress in SACs to display their synthesis, characterization, and performance in catalyzing the water electrolysis process. Some emphasis has been given to the development of SACs concerning the novel supports, fabrication strategies, and the functional mechanisms of the catalytic processes.