A novel CeO2 nanowire catalyst prepared by the Freeze-Drying method with significantly improved catalytic performance for toluene oxidation

A wire like CeO2 catalyst (CeO2-w) was obtained after the calcination of the precursor at 400 °C, which was prepared by the freeze-drying method for the first time. It shows good performance for catalytic oxidation of toluene with T90 of 220 °C, which is much better than the CeO2 catalysts with other structures prepared by the different methods. The good performance of CeO2-w is due to the bigger pore volume, more active oxygen species, more oxygen vacancies, better low temperature reducibility, higher surface area normalized reaction rates and lower Ea value. Additionally, the CeO2-w catalyst exhibits good water resistance and catalyst stability. In situ DRIFTS indicates the catalytic oxidation of toluene on CeO2-w undergoes the progress of toluene → benzaldehyde → benzoic acid → maleic acid → CO2 and H2O. This work affords a new idea to prepare high active CeO2 nanowire catalysts for catalytic oxidation of toluene, and open an efficient way for the construction of CeO2 based composite catalysts for VOCs degradation.