Highly stable, mesoporous mixed lanthanum–cerium oxides with tailored structure and reducibility
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Pure and mixed lanthanum and cerium oxides were synthesized via a reverse microemulsion-templated route. This approach yields highly homogeneous and phase-stable mixed oxides with high surface areas across the entire range of La:Ce ratios from pure lanthana to pure ceria. Surprisingly, all mixed oxides show the fluorite crystal structure of ceria, even for lanthanum contents as high as 90%. Varying the La:Ce ratio not only allows tailoring of the oxide morphology (lattice parameter, pore structure, particle size, and surface area), but also results in a fine-tuning of the reducibility of the oxide which can be explained by the creation of oxygen vacancies in the ceria lattice upon La addition. Such finely controlled syntheses, which enable the formation of stable, homogeneous mixed oxides across the entire composition range, open the path towards functional tailoring of oxide materials, such as rational catalyst design via fine-tuning of redox activity.
KeywordsCeria CeO2 Mixed Oxide La2O3 Cerium Oxide
This work was supported by the National Energy Technology Laboratory’s on-going research under the RDS contract DE-AC26-04NT41817; by the Department of Energy—Basic Energy Science through Grant DE-FG02-05ER46233; and by the National Science Foundation through Grant CTS-0553365. G.V. gratefully acknowledges a CNG faculty fellowship of the University of Pittsburgh’s Swanson School of Engineering, and a faculty fellowship from DOE-NETL.
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