Efficient electrocatalytic reduction of nitrate to ammonia using Cu–CeO2 solid solution.

Electrocatalytic nitrate reduction reaction (EC-NITRR) is expected to replace Haber-Bosch process for green ammonia (NH 3) production. Currently, many catalysts often result in low NH 3 yields and low faraday efficiencies due to the lack of active sites. In this study, Cu-doped CeO 2 solid solution catalyst was prepared for EC-NITRR using transition metal ions doping. The addition of Cu significantly improved the oxygen vacancy (O v) concentration of CeO 2 and provided more active sites for NO 3 − catalysis. Meanwhile, the internal charge transfer capability and surface catalytic kinetics of the catalyst are enhanced by the excellent redox capability of Ce3+ and Cu+. Compared with bare CeO 2 , the NH 3 yield of 7% Cu–CeO 2 increased by 1.88 times. This work provides new ideas for the design of green and efficient catalysts for EC-NITRR by identifying the role of Cu in the mechanism of doping regulation of CeO 2. The incorporation of Cu into CeO 2 lattice realizes the synergistic regulation of oxygen vacancy and active sites, which contributes to the desirable Faraday efficiency of 88.15% for electrochemical nitrate reduction. [Display omitted] • 7% Cu–CeO 2 solid solution was fabricated via electrodeposition. • Cu incorporation significantly increased the O v concentration in CeO 2. • The interaction between Cu+ and Ce3+ enhanced the internal charge transfer capability of the catalyst. • 170.56 μg h−1 cm−2 NH 3 yield and 88.15% Faraday efficiency were achieved. [ABSTRACT FROM AUTHOR]