Effect of Pd/Ce loading on the performance of Pd–Ce/γ-Al2O3 catalysts for toluene abatement. (July 2020)

• Record Type: Journal Article
• Authors: Ren, Sida; Liang, Wenjun; Li, Qinglei; Zhu, Yuxue
• Is Part Of: Chemosphere. Volume 251(2020)
• Publication Date: 2020-07
• Subjects: Catalysis -- CeO2 -- Oxygen vacancies -- Pd -- Toluene; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2020.126382
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: A single metal Pd/γ-Al2 O3 catalyst and a bimetallic Pd–Ce/γ-Al2 O3 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 N2 desorption, scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), H2 -TPR, O2 -TPD, and electron paramagnetic resonance (EPR). The results showed that bimetal catalysts loaded CeO2 had smaller nano-PdO particles than those of the Pd/γ-Al2 O3 catalyst. Compared with the catalyst of 0.2Pd/γ-Al2 O3 (percentage of mass, the same as below), the catalyst doped with 0.3CeO2 had a stronger reduction peak, which was shifted to the low-temperature zone by more than 80 °C. The results of XPS and O2 -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 O2 increased from 3.55 μmol/g to 8.54 μmol/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 O2 and PdO during the Ce 3+ toCe 4+ 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/γ-Al2 O3 catalyst were decreased by 22 °C and 40 °C, respectively. Graphical abstract: Image 1 Highlights: The interaction of Pd/Ce bimetals for toluene catalytic oxidation was investigated. A mass ratio of 2:3 was optimum for the Pd and CeO2 in the Pd–Ce–Al catalyst. A good low-temperature catalytic activity for toluene was found, and T 10 was lower than 150 °C.