Effect of Pd/Ce loading on the performance of Pd-Ce/γ-Al2O3 catalysts for toluene abatement

A single metal Pd-Ce/gamma-Al2O3 catalyst and a bimetallic Pd-Ce/gamma-Al2O3 catalyst were prepared by the equal-volume impregnation method to investigate the effect of CeO2 loading on the catalytic oxidation of toluene. The specific surface area, surface morphology, and redox performance of the catalyst were characterized by N-2 desorption, scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), H-2-TPR, O-2-TPD, and electron paramagnetic resonance (EPR). The results showed that bimetal catalysts loaded CeO2 had smaller nano-PdO particles than those of the Pd-Ce/gamma-Al2O3 catalyst. Compared with the catalyst of 0.2Pd-Ce/gamma-Al2O3 (percentage of mass, the same as below), the catalyst doped with 0.3CeO(2) had a stronger reduction peak, which was shifted to the lowtemperature zone by more than 80 degrees C. The results of XPS and O-2-TPD showed that the introduction of CeO2 provided more surface oxygen vacancy for the catalyst and enhanced its catalytic oxidation ability, and the amount of desorbed O-2 increased from 3.55 mu mol/g to 8.54 mu mol/g. The results of EPR were that the addition of CeO2 increased the content of active oxygen species and oxygen vacancies on the surface of the catalysts, which might be due to the supply of electrons to the O-2 and PdO during the Ce(3+)to Ce4+ conversion process. That could have accelerated the catalytic reaction process. Compared with the single precious metal catalyst, the T-10 and T-90 of the Pd-Ce/gamma-Al2O3 catalyst were decreased by 22 degrees C and 40 degrees C, respectively. (C) 2020 Elsevier Ltd. All rights reserved.