Fe and Cu Double-Doped Co<sub>3</sub>O<sub>4</sub> Nanorod with Abundant Oxygen Vacancies: A High-Rate Electrocatalyst for Tandem Electroreduction of Nitrate to Ammonia
Maosen Song, Yuxuan Xing, Yudong Li, Dan Liŭ, Enshan Han, Yang Gao, Ziyi Yang, Xiaohui Yang, Yanzhen He
Abstract
The electrochemical nitrate reduction reaction (NO 3 RR) is an attractive green alternative to the conventional Haber–Bosch method for the synthesis of NH 3 . However, this reaction is a tandem process that involves multiple steps of electrons and protons, posing a significant challenge to the efficient synthesis of NH 3 . Herein, we report a high-rate NO 3 RR electrocatalyst of Fe and Cu double-doped Co 3 O 4 nanorod (Fe 1 /Cu 2 -Co 3 O 4 ) with abundant oxygen vacancies, where the Cu preferentially catalyzes the rapid conversion of NO 3 – to NO 2 – and the oxygen vacancy in the Co 3 O 4 substrate can accelerate NO 2 – reduction to NH 3 . In addition, the introduction of Fe can efficiently capture atomic H* that promotes the dynamics of NO 2 – to NH 3, improving Faradaic efficiency of the produced NH 3 . Controlled experimental results show that the optimal electrocatalyst of Fe 1 /Cu 2 -Co 3 O 4 exhibits good performance with high conversion (93.39%), Faradaic efficiency (98.15%), and ammonia selectivity (98.19%), which is significantly better than other Co-based materials. This work provides guidance for the rational design of high-performance NO 3 RR catalysts.