NH3 synthesis via visible-light-assisted thermocatalytic NO reduction by CO in the presence of H2O over Cu/CeO2

A photothermal catalytic system comprising Cu/CeO2 was applied to the reaction between NO, CO and H2O for the production of NH3 under visible-light irradiation. High NO conversion (94.4%) and NH3 selectivity (66.5%) were achieved over Cu/CeO2 in the presence of H2O at 210 °C. Visible light further improved the conversion of NO (97.7%) and selectivity for NH3 (69.1%). The quasi-situ EPR and in-situ DRIFTS results indicated that CO initially reacts with H2O to form an HCO3* intermediate, which then decomposes into CO2 and activated H*. Finally, NO reacts with activated H* to produce NH3. The localized surface plasmon resonance effect of Cu nanoparticles induced by visible light promotes the decomposition of HCO3* to CO2 and H*, while regenerating oxygen vacancies (OVs, H2O activation sites) at the CeO2 sites, resulting in enhanced NH3 production. This study offers a convenient approach for NH3 production under mild conditions.