Defect Engineering in Cubic Cerium Oxide Nanostructures for Catalytic Oxidation

Abstract

Traditional nanostructured design of cerium oxide catalysts typically focuses on their shape, size, and elemental composition. We report a different approach to enhance the catalytic activity of cerium oxide nanostructures through engineering high density of oxygen vacancy defects in these catalysts without dopants. The defect engineering was accomplished by a low pressure thermal activation process that exploits the nanosize effect of decreased oxygen storage capacity in nanostructured cerium oxides.

Effects of Morphology of Cerium Oxide Catalysts for Reverse Water Gas Shift Reaction

“…AC-HRTEM studies providing sub-angstrom resolution [22,24], clearly revealed (111) crystal planes exposed at ceria rods and particles [25,31,62,63], whereas ceria cubes are enclosed by mainly (100) facets [18]. These ceria nanoshapes exhibited exactly the same trends in activity per surface area for WGS reaction (decreasing from ceria cubes to rods and finally particles) as reported in this study on RWGS reaction (Fig.…”

CO Oxidation Mechanism on CeO2-Supported Au Nanoparticles

“…17 Localized electrons on the occupied 4f-orbital of Ce 3+ ions contribute to the electronic interaction between reduced CeO 2 and supported Au NPs. 15,19 CeO 2 -supported Au is regarded as a promising catalytic system, because it combines highly active components, Au NPs and CeO 2 .…”

“…18 Lawrence et al recently demonstrated that catalytic activity is a function of the concentration of oxygen vacancies for the CO oxidation activity of CeO 2 nanorods, NPs, and the bulk surface. 17 Oxygen vacancy formation on the CeO 2 surface accompanies the reduction of adjacent Ce 4+ ions to Ce…”

Gd–Bi–Ce–O materials as catalysts in CO oxidation

“…This leads to the relative stability of the low index ceria surfaces following the trend: (111) [ (110) [ (100), but the formation energies of oxygen vacancies on different planes of ceria vary, following the order: (110) \ (100) \ (111), and the frequency of use of crystalline planes has the order: (100) \ (110) \ (111). So, the higher catalytic activity is due to the exposed (100) and (110) planes (form of particles: spindle-shaped, rods, cubes), but ceria nanoparticles preferentially expose stable (111) planes (Wu et al 2012;Lawrence et al 2011;Na et al 2008;Mai et al 2005;Lundberg et al 2004;Sayle et al 2002). FTIR spectra (Fig.…”