Low content of CoOx supported on nanocrystalline CeO2 for toluene combustion: The importance of interfaces between active sites and supports

Abstract

A low content of CoOx (1 wt% Co loading) was deposited on CeO2 nanoparticles (CoCe-P), nanorods (CoCe-R) and nanocubes (CoCe-C) for toluene oxidation. The CoCe-P catalyst showed a significantly higher activity than CoCe-R or CoCe-C. Compared with CoCe-C, the temperature of toluene conversion (T90 = 90% and T50 = 50%) for CoCe-P decreased by ΔT90 = 86 °C and ΔT50 = 60 °C. The reaction rate (r, mol m−2 s-1) of the CoCe-P catalyst at 220 °C increased by nine times. The low content of CoOx formed as either nanoparticles or highly dispersed species on the surfaces of different CeO2 nanostructures. The different interactions between CoOx and CeO2 are intrinsically relevant to the various redox and catalytic properties. There exists a synergistic effect at the interface between CoOx and CeO2. Highly dispersed CoOx species and the increased oxygen vacancies at the interface led to the excellent performance of CoCe-P for toluene oxidation.