Research progress and applications of nickel-based catalysts for electrooxidation of urea

The combination of wastewater treatment and energy production is a hot issue that meets the current requirements of sustainable development. The direct discharge of large amounts of urea-rich wastewater without treatment will pose a serious threat to the environment and human health. Urea electrooxidation can realize wastewater restoration and transform energy at the same time. However, due to the 6e− transfer process of the urea oxidation reaction, the kinetics is sluggish, and exploring efficient catalysts for urea electrooxidation brooks no delay to improve. Nickel is considered to be an effective catalytic component of urea oxidation reaction, with low cost and good catalytic activity. This article reviews the recent research progress of nickel-based urea electrooxidation catalysts and makes a detailed comment on the four applications of wastewater remediation, hydrogen production, fuel cells, and urea sensors. Moreover, the development prospects and challenges faced by nickel-based catalysts and their practical applications are discussed.