Finely Tuned Structure and Catalytic Performance of Cerium Oxides by a Continuous Samarium Doping from 0 to 100.

Author(s) Tao, R.; Xu, J.; Zhong, H.; Wen, W.; Pan, Q.; Liu, Y.; Chen, J.
Journal Inorg Chem
Date Published 2019 Oct 07
Abstract

Cerium oxides are prevalent catalytic materials, and the lanthanide-doped ceria have attracted special interest since it is easy to tune the concentration of oxygen vacancies (V) by changing the doping content. The presence of V is generally believed to favor a catalytic reaction, but the formation of dopant-vacancy associations at a high doping concentration might produce an adverse effect. Herein, evolutions of the structural properties and catalytic performances in Sm-doped ceria (SmCeO, = 0-1) are investigated to explore the doping effect of Sm on the ceria-based nanoctrystals. The SmCeO films composed of nanoctrystals are elaborately prepared via electrodeposition under mild conditions to prevent phase separation. A combination of studies, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman, photoluminescence (PL), and methanol electro-oxidation (MEO) reaction, reveals that variation trends for the V concentration and catalytic property of SmCeO are unsynchronized. The lattice structures of SmCeO nanoctrystals undergo a smooth and steady transition from F-type (fluorite CeO) to C-type (cubic SmO) with the increase of Sm contents. The structural transition occurs in the Sm concentration range of 64-84%, within which the V concentration reaches the maximum as well. However, the optimal MEO performance is obtained at a relatively lower doping concentration of 24%. Above this concentration, significant dopant-vacancy associates are observed by XRD, Raman, and PL characterizations. It is inferred that, for these ceria-based nanocrystals, the dopant-vacancy association induced by high doping would impede the growth of catalytic performance despite all the benefits of V.

DOI 10.1021/acs.inorgchem.9b01979
ISSN 1520-510X
Citation Tao R, Xu J, Zhong H, Wen W, Pan Q, Liu Y, et al. Finely Tuned Structure and Catalytic Performance of Cerium Oxides by a Continuous Samarium Doping from 0 to 100. Inorg Chem. 2019;58(19):13066-13076.

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