Regulating active oxygen species and acidity of Ca doped LaMnO3 perovskite catalysts toward efficient n-butylamine oxidation

It is of great significance to design catalysts with high activity, N2 selectivity and stability for nitrogen-containing volatile organic compound (NVOC) catalytic purification. Meanwhile, the role of oxygen species in NVOC catalytic oxidation is still ambiguous. Herein, the oxygen species of La-Mn perovskite catalysts were engineered by doping Ca in La site to elucidate their role in catalytic n-butylamine oxidation. Results demonstrate that La0.9Ca0.1MnO3 exhibits the highest activity owing to its abundant adsorbed oxygen species and high surface area, achieving 100 % n-butylamine conversion (500 ppm; GHSV=60,000 mL g−1h−1) at 200 °C with N2 selectivity of ca. 95 %. More adsorbed oxygen species generated due to Ca doping accelerates the oxidation rate and C-C cleavage of alcohol and acetate intermediates, resulting in higher CO2 yield. Meanwhile, Ca-doping also modifies the acidity of catalysts, which affects the adsorption/desorption process of alkaline substances and yield of nitrogen-containing products. In addition, La0.9Ca0.1MnO3 shows superior stability, high water and SO2 resistance, and acceptable activity for other common NVOCs, demonstrating a promising catalyst for NVOC oxidation even under harsh operation conditions. Furthermore, the toxic effect of pollutant or products during n-butylamine catalytic oxidation on the growth of Chlorella Vulgaris was investigated and results suggest that catalytic oxidation is an environmentally friendly method for NVOC purification. This work sheds light on the relationships among oxygen species, catalyst acidity, and n-butylamine catalytic oxidation, which expand the understanding of rational design of efficient catalyst for NVOC oxidation.