Preparation and reaction mechanism of novel Ce Co Cu oxide composite catalysts towards oxidation of o-xylene

CexCoyCuz oxide composite catalysts were prepared by using polyethylene glycol, citrate sol–gel method combined with PMMA template for the oxidation of o-xylene. The catalysts were characterized by the X-ray diffraction (XRD), H2-temperature programmed reduction (H2-TPR), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR), etc. The catalytic activity for o-xylene was investigated. The catalytic degradation pathway and mechanism of o-xylene were inferred. The results show that CeO2 is mainly present on the surface of all catalysts. The surface area of Ce2Co1Cu1 is up to 77.2 m2/g, and the average pore size is 10.62 nm. It exhibits redox and sufficient Ce4+ and Ce3+, and reactive oxygen species, and has maximum O–H and CO in the five catalyst samples. The catalytic activity of Ce2Co1Cu1 is the best at low temperature, with the T50 and T90 values of 235 and 258 °C at a space velocity of 32000 h−1, respectively. The o-xylene is oxidized to o-methyl benzaldehyde, and then further oxidized to o-methylbenzoic acid, and finally CO2 and H2O are formed.