RESUMEN
The electrochemical nitrate reduction reaction (NO3RR) is an attractive green alternative to the conventional Haber-Bosch method for the synthesis of NH3. However, this reaction is a tandem process that involves multiple steps of electrons and protons, posing a significant challenge to the efficient synthesis of NH3. Herein, we report a high-rate NO3RR electrocatalyst of Fe and Cu double-doped Co3O4 nanorod (Fe1/Cu2-Co3O4) with abundant oxygen vacancies, where the Cu preferentially catalyzes the rapid conversion of NO3- to NO2- and the oxygen vacancy in the Co3O4 substrate can accelerate NO2- reduction to NH3. In addition, the introduction of Fe can efficiently capture atomic H* that promotes the dynamics of NO2- to NH3, improving Faradaic efficiency of the produced NH3. Controlled experimental results show that the optimal electrocatalyst of Fe1/Cu2-Co3O4 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 NO3RR catalysts.
RESUMEN
The adsorption of nitrate is the key to enhancing the electrocatalytic nitrate reduction reaction (NitRR). Herein, a typical hydrolysis-coupled redox (HCR) reaction has been designed to prepare unique 3D Cu/Fe2O3 core-shell nanorod array cathodes with controllable oxygen vacancy concentrations for NitRR. The optimal Cu/Fe2O3-13 achieves a high nitrate conversion of 99.10% and ammonia selectivity of 98.30%. The outstanding electrochemical performance is attributed to the enhancement mechanism of OVs and a unique nanorod array structure with a high density of surface-exposed OVs and high-throughput transport pathways for ion-aspects.