Morphology-dependent properties of CeO2 nano-catalysts on CH2Cl2 oxidation

Abstract

Four types of CeO₂ nanoparticles with different morphologies (nanorods, nanocubes, nanopolyhedra, and bulk CeO₂ nanoparticles) were synthesized and used in dichloromethane (DCM) oxidation. Their detailed physicochemical properties were investigated by X-ray diffraction, N₂ physisorption, H₂ temperature-programmed reduction, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy. Results indicated that DCM oxidation over CeO₂ nanoparticles has significant morphology-dependent effects. CeO₂ nanorods showed the best activity among all the investigated samples (T₉₀ is only 323 °C). The main products were CO₂ and HCl, although trace amounts of CHCl₃, CCl₄, CO, and Cl₂ could be detected. The high performance of CeO₂ nanorods in DCM oxidation may be related to the abundant surface defects, increased amount of adsorbed active oxygen species, and good reducibility of the catalyst.