Complete Oxidation of CO, Propene, and Toluene as Model Components of Diesel Engine Exhaust and VOC using Ceria-modified Cu/Hydroxyapatite: Effect of Preparation Methods and Ce Concentration

Abstract The Ce-modified Cu/HAp catalyst was prepared by successive deposition and coprecipitation methods and was investigated for propene oxidation serving as a model component of diesel engine exhaust and volatile organic components (VOCs). The Cu0.4/Ce0.1/HAp catalyst prepared by successive deposition showed better performance than the Cu0.4–Ce0.1/HAp catalyst prepared by the coprecipitation method. Furthermore, the Ce concentration has been optimized using successive deposition methods. The catalyst was modified with 0.4 mol Cu and 0.1 mol Ce deposited on HAp and tested for CO, propene, and toluene oxidation. Complete conversion is attained by the Cu0.4/Ce0.1/HAp catalyst at approximately 339 °C, highlighting its superior low-temperature activity compared with the remaining Ce-modified Cu/HAp catalyst series. All catalysts were characterized by P-XRD, BET, Raman, XPS, ATR-FTIR, H2-TPR, FESEM, and HR-TEM techniques. The formation of facile CuO x species with more Ce3+ and adsorbed oxygen was observed in the Cu0.4/Ce0.1/HAp catalyst. These species are responsible for the oxidation of propene at lower temperatures compared to the remaining catalyst.