Cobalt-Oxide-Based Materials as Water Oxidation Catalyst: Recent Progress and Challenges

Inspired by natural processes, there is an enormous interest in light-driven water splitting to convert solar energy into electrical and chemical energy. This approach is thought to be able to eventually solve the main energy problem that society will face more dramatically in the near future. The water oxidation reaction is widely considered a major barrier for utilizing solar energy in artificial photosynthesis. Due to the relatively high overpotential and slow kinetics of the reaction, numerous efforts are made on the development of non-noble metal oxygen evolution catalysts such as transition metal oxides. Among them, cobalt-oxide-based materials have shown decent activity and thus present themselves as a promising candidate. In this perspective, we summarize the state of the art in synthesis of cobalt-oxide-based materials and application as water oxidation catalysts through electrochemical, photochemical, and photoelectrochemical approaches. Additionally, we state the future challenges that are critical to overcome to push the catalyst performance one step further.