Effects of cerium incorporation on the catalytic oxidation of benzene over flame-made perovskite La1-xCexMnO3 catalysts

• Published in: Particuology 2015-04, Vol.19 (2), p.60-68
• Main Authors: Liu, Gang, Li, Jiaqi, Yang, Kun, Tang, Wenxiang, Liu, Haidi, Yang, Jun, Yue, Renliang, Chen, Yunfa
• Format: Article
• Language: English
• Subjects: Benzene elimination; Ce substitution; Charge neutralization; Flame spray pyrolysis; Perovskite; X射线光电子能谱; 催化剂; 掺入; 氧化铈; 火焰; 程序升温还原; 苯; 钙钛矿型
• ISSN: 1674-2001; 2210-4291
• DOI: 10.1016/j.partic.2014.07.001

Perovskite-type La1-xCexMnO3 （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 ℃. 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 Ce^4＋ resulted in modification of the chemical states of both B-site ions and oxygen species and facilitated the reducibility of the perovskite. The surface Mn^4＋/Mn^3＋ ratio was increased as a result of Ce^4＋ substitution, while a decrease in the surface-adsorbed O/lattice O （Oads/Olatt） 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.