Influence of isovalent and aliovalent dopants on the reactivity of cerium oxide for catalytic applications

Synthesis and application of rare-earth elements (Gd, Sm, and Nd) doped ceria-based solid solutions for methyl mercaptan catalytic decomposition

“…Since the ionic radii of these trivalent RE dopants and the tetravalent cerium ion are as follows: Gd 3+ (1.05 Å), Sm 3+ (1.08 Å), Nd 3+ (1.11 Å) and Ce 4+ (0.97 Å) [20,21]. Therefore, the introduction of larger sized dopants into ceria lattice would enlarge the octahedral site of unit cell in fluorite oxide, which causes the diffraction peaks to shift to lower angle positions [22]. Moreover, this is further proved by the obtained lattice parameter and crystallite size values, which are not quite the same as the pure CeO 2 and presented in Fig.…”

“…The relative Ce 3+ concentration can be determined by the ratio: Ce 3+ /(Ce 4+ + Ce 3+ ), where Ce 4+ and Ce 3+ represent the sums of the spectral peak areas related to the Ce 4+ and Ce 3+ , respectively [32]. The calculated results are listed in Table 1 species in pure CeO 2 mainly points out that the sample has not been fully oxidized, rather than represents for the formation of oxygen vacancies [22]). This phenomenon could be ascribed to the synergistic interaction between Gd and Ce oxides (as mentioned in the section of XRD characterization), which leads to the facilitation of redox cycles between Ce 3+ and Ce 4+ [32].…”

Design of Ceria Catalysts for Low‐Temperature CO Oxidation

“…Even though a few studies investigated the activity of RDC catalysts, the effects of RE dopants on CO oxidation are still not clear due to the controversies surrounding the relative order of activities of RDC catalysts. [71][72][73][74][75][76] Our group previously studied the effects of RE-dopants on the intrinsic reactivity by cautiously controlling the geometric factors such as particle size and surface area, which might have contributed to inconsistency in previous reports. [32] The CO oxidation activities were first experimentally measured with pure and Pr, Nd, and Sm-doped CeO 2 (PDC, NDC, and SDC, respectively) using controlled RE-doping concentrations and geometric factors, demonstrating the activity in the following order: CeO 2 > PDC > NDC > SDC.…”

Enhanced Catalytic Performance of Manganese and Cobalt Co–doped CeO2 Catalysts for Diesel Soot Oxidation

“…Figure represent the correlation of 50 % soot oxidation performance (T 50 ) of codoped ceria (CMC773) catalyst with that of Ce‐Zr, Ce‐Gd,Ce–La, Ce‐Pr, Ce‐Sm, and Ce‐Eu solid solutions obtained by similar preparation method.…”

“…The T 50 values of investigated catalysts increased in the order of CMC773 (636 K) < CC773 (677 K) < CM773 (757 K) < C773 (874 K) < unanalysed (920 K). Figure 11 represent the correlation of 50 % soot oxidation performance (T 50 ) of codoped ceria (CMC773) catalyst with that of Ce-Zr, [14] Ce-Gd, [35] Ce-La, [14] Ce-Pr, [36] Ce-Sm, [37] and Ce-Eu [38] solid solutions obtained by similar preparation method.…”