Performance of ammonia catalytic combustion over Cu-CeOx catalyst and the impact of oxygen concentration

Abstract

Ammonia has long been regarded as a high-quality zero-carbon fuel; however, limitations in its combustion characteristics have restricted its practical applications. Catalytic combustion is considered an effective solution to overcome the challenges associated with ammonia combustion. In this study, we successfully synthesized a copper-cerium binary catalyst (Cu-CeOx) using the sol-gel method, demonstrating outstanding performance for NH3 catalytic combustion. Through in-situ DRIFTS results, we observed that the 15Cu-CeOx catalyst exhibits both i-SCR and -NH mechanisms. The oxygen concentration affects the N2 selectivity by modulating the overoxidation of NH3. Under high oxygen concentrations, high temperatures promote the excessive oxidation of NH3, and ammonia combustion through the i-SCR mechanism. Conversely, the oxygen concentration was equal to NH3 reaction stoichiometry, the overoxidation of NH3 is limited, and ammonia combustion proceeds through the NH mechanism, resulting in higher N2 selectivity.