In Situ Construction of Cu ⁺ ‐O _v ‐Ce ³⁺ Sites on CeO ₂ for Efficient NH ₃ Oxidation

Abstract Ammonia (NH ₃ ) emissions adversely affect both the environment and human health. The selective catalytic oxidation of NH ₃ (NH ₃ ‐SCO) holds great promise for NH ₃ abatement; however, there remains a lack of cost‐effective NH ₃ ‐SCO catalysts with high activity and N ₂ selectivity for practical applications. This study reports on a strategy for constructing an outstanding NH ₃ oxidation catalyst via the in situ doping of Cu into CeO ₂ nanorods. The designed CeCuO _x nanorod catalyst shows remarkable activity, N ₂ selectivity, and stability for NH ₃ oxidation, achieving complete conversion below 250 °C, with ≈80% N ₂ selectivity. The results of various characterization tests and density functional theory (DFT) calculations show that the addition of Cu induces the formation of abundant Cu ⁺ ‐O _v ‐Ce ³⁺ active sites on the CeO ₂ , which are beneficial for the adsorption and activation of reactants. Additionally, in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) confirms that the addition of Cu switches the primary intermediate species of NH ₃ oxidation from bidentate nitrate species to monodentate nitrate species, which accelerates the rate‐determining step of NH ₃ ‐to‐N ₂ oxidation. Therefore, doping Cu into CeO ₂ greatly improves its NH ₃ oxidation activity and N ₂ selectivity. This study provides valuable insights into the construction of highly active sites for NH ₃ oxidation.