Effects of cerium incorporation on the catalytic oxidation of benzene over flame-made perovskite La1−xCexMnO3 catalysts--颗粒学报PARTICUOLOGY

Liu, G., Li, J., Yang, K., Tang, W., Liu, H., Yang, J., Yue, R., & Chen, Y. (2015). Effects of cerium incorporation on the catalytic oxidation of benzene over flame-made perovskite La1−xCexMnO3 catalysts. Particuology, 19, 60–68. https://doi.org/10.1016/j.partic.2014.07.001

Effects of cerium incorporation on the catalytic oxidation of benzene over flame-made perovskite La_1−xCe_xMnO₃ catalysts

Gang Liu^{a b}, Jiaqi Li ^{a b}, Kun Yang ^a, Wenxiang Tang ^{a b}, Haidi Liu ^a, Jun Yang ^a, Renliang Yue^a *, Yunfa Chen ^a *

a State Key Laboratory of Multi-phase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
b University of Chinese Academy of Sciences, Beijing 100049, China

10.1016/j.partic.2014.07.001

Volume 19, April 2015, Pages 60-68

Received 3 March 2014, Revised 29 April 2014, Accepted 10 July 2014, Available online 13 August 2014.

E-mail: rlyue@ipe.ac.cn; yfchen@ipe.ac.cn

Highlights

• Change in specific surface area has less impact on the catalytic activity of benzene oxidation.

• Mn⁴⁺/Mn³⁺ increased and O_ads/O_latt decreased with Ce⁴⁺ substitution.

• Surface element species ratios correlated with catalytic activity.

Abstract

Perovskite-type La_1−xCe_xMnO₃ (x = 0–10%) catalysts were prepared by flame spray pyrolysis and their activities during the catalytic oxidation of benzene were examined over the temperature range of 100–450 °C. The structural properties and reducibility of these materials were also characterized by X-ray diffraction (XRD), N₂ adsorption/desorption, H₂ temperature-programmed reduction (H₂-TPR) and X-ray photoelectron spectroscopy (XPS). The incorporation of Ce was found to improve the benzene oxidation activity, and the perovskite in which x was 0.1 exhibited the highest activity. Phase composition and surface elemental analyses indicated that non-stoichiometric compounds were present. The incorporation of Ce had a negligible effect on the specific surface area of the perovskites and hence this factor has little impact on the catalytic activity. Introduction of Ce⁴⁺ resulted in modification of the chemical states of both B-site ions and oxygen species and facilitated the reducibility of the perovskite. The surface Mn⁴⁺/Mn³⁺ ratio was increased as a result of Ce⁴⁺ substitution, while a decrease in the surface-adsorbed O/lattice O (O_ads/O_latt) ratio was observed. The relationship between the surface elemental ratios and catalytic activity was established to allow a better understanding of the process by which benzene is oxidized over perovskites.

Graphical abstract

Keywords

Perovskite; Benzene elimination; Ce substitution; Flame spray pyrolysis; Charge neutralization

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