Physicochemical properties of nanostructured Pd/lanthanide-doped ceria spheres with high catalytic activity for CH₄combustion

Abstract

Nanostructured 1 wt% Pd/LnDC spheres exhibited high activity for CH4 oxidation with total conversion of CH4 attained at a temperature below 400 °C.

Structure-activity relationship in Pd/CeO2 methane oxidation catalysts

“…Indeed, in earlier papers it was already reported that Pd and ceria had a strong influence on the reciprocal redox behavior with palladium promoting low temperature CeO2 reduction and CeO2 promoting Pd oxidation [30,31], a situation confirmed also in more recent works [32][33][34]. The effect of ceria in the promotion of Pd oxidation, as suggested by Farrauto et al [18], has substantial implications for the high temperature methane oxidation activity of Pd-based catalysts and, if in the past this was mainly studied for energy production applications, at present it should be taken into account when considering for example close coupled three-way catalysts for methane abatement.…”

“…Other formulations involving close coupled Pd and ceria have been proposed in the literature, with Pd and ceria in separate domains interacting with each other [33,64,[96][97][98][99][100][101] or in which Pd is inserted into the lattice of ceria [17,20,22,40,43,46,54,102]. Regarding the first class of materials, it should be highlighted that in many cases from the characterization it is not clear whether they also might include Pd-Ce solid solutions, and the various catalyst configurations (nanosheets, nanospheres, Pd and ceria confined into porous supports etc.)…”

Enhanced Artificial Enzyme Activities on the Reconstructed Sawtoothlike Nanofacets of Pure and Pr-Doped Ceria Nanocubes

“… 18 , 21 , 22 In particular, Pr can greatly improve the oxygen storage capacity of ceria because of its redox Pr 3+ /Pr 4+ couple. 21 , 23 , 24 …”

“…18,21,22 In particular, Pr can greatly improve the oxygen storage capacity of ceria because of its redox Pr 3+ /Pr 4+ couple. 21,23,24 Though many reports are available on various methodologies, synthesizing enzymatic nanocrystals with controlled size and surface through a single method still remains a challenge. Yang nanorods (NRs) exposing different facets via a hydrothermal method.…”

“…on nanoceria’s functions as artificial enzymes, more investigations have been focused on tuning its enzymelike kinetics and performance. ,− Previous studies indicate that ceria with controlled morphologies presents outstanding properties, different from those of conventional ceria particles. ,, The exposure of more active facets, which might facilitate the redox cycles, in the case of nanoceria with well-defined shapes must be at the roots of this enhancement of the enzyme-mimic activity . Doping ceria with other elements, such as other lanthanides or aliovalent cationic metal dopants, can enhance the redox properties of ceria due to an increase in the concentration of oxygen vacancies and oxygen mobility in ceria. ,, In particular, Pr can greatly improve the oxygen storage capacity of ceria because of its redox Pr 3+ /Pr 4+ couple. ,, …”