Vacancy-Driven Ammonia Electrooxidation Reaction on the Nanosized CeO<sub><i>x</i></sub> Electrode in Nonaqueous Electrolyte
Xue Yang, Lu Sun, Xingyu Liu, Zekai Yang, Han Sun, Weiwei Liu, Haijun Chen
Abstract
The vacancy-engineering strategy has been successfully employed for electrochemical conversion by modulating the electronic structure and reaction kinetics of metal oxide-based electrode materials. The electrolysis of ammonia into hydrogen and nitrogen under mild conditions would be beneficial for utilizing ammonia as a zero-carbon fuel for mobile applications, such as cars and ships. Although platinum has been studied as the most effective state-of-the-art electrocatalyst for ammonia electrolysis, its high cost and rapid deactivation due to nitride poisoning make it difficult to be used commercially. Herein, we report that nanosized cerium oxides (CeO x ) demonstrate highly efficient activity and enhanced stability for ammonia electrolysis in a nonaqueous electrolyte system. The Faradaic efficiency of N 2 is approximately double that of a commercial Pt/C electrode, while its onset potential is lower than that of the latter. Cerium oxide with vacancy sites was found to be more favorable for NH 3 adsorption and exhibits a significantly lower energy barrier for the initial step of NH 3 dissociation compared to CeO 2 . Consequently, this contributes to the heightened activity of ammonia electrolysis on the electrode of cerium oxide following the G–M mechanism.