Catalytic properties of Pt cluster-decorated CeO2 nanostructures

Abstract

Uniform clusters of Pt have been deposited on the surface of capping-agent-free CeO 2 nanooctahedra and nanorods using electron beam (e-beam) evaporation. The coverage of the Pt nanocluster layer can be controlled by adjusting the e-beam evaporation time. The resulting e-beam evaporated Pt nanocluster layers on the CeO 2 surfaces have a clean surface and clean interface between Pt and CeO 2 . Different growth behaviors of Pt on the two types of CeO 2 nanocrystals were observed, with epitaxial growth of Pt on CeO 2 nanooctahedra and random growth of Pt on CeO 2 nanorods. The structures of the Pt clusters on the two different types of CeO 2 nanocrystals have been studied and compared by using them as catalysts for model reactions. The results of hydrogenation reactions clearly showed the clean and similar chemical surface of the Pt clusters in both catalysts. The supportdependent activity of these catalysts was demonstrated by CO oxidation. The Pt/CeO 2 nanorods showed much higher activity compared with Pt/CeO 2 nanooctahedra because of the higher concentration of oxygen vacancies in the CeO 2 nanorods. The structure-dependent selectivity of dehydrogenation reactions indicates that the structures of the Pt on CeO 2 nanorods and nanooctahedra are different. Thes differences arise because the metal deposition behaviors are modulated by the strong metal-metal oxide interactions.

Room-Temperature Magnetism of Ceria Nanocubes by Inductively Transferring Electrons to Ce Atoms from Nearby Oxygen Vacancy

“…The uniform organic-capping-free CeO 2 nanocubes were synthesized using a hydrothermal process [22]. Briefly, 434.3 mg of Ce(NO 3 ) 3 ·6H 2 O and 1.6 mg of Na 3 PO 4 were mixed in 40 mL deionized water and sonicated for 30 min.…”

Promotion of Pt/CeO2 catalyst by hydrogen treatment for low-temperature CO oxidation

“…Regarding the support materials, the most widely used reducible support is ceria (CeO 2 ): the fascinating property of ceria which renders it useful for CO oxidation is its oxygen storage capacity (OSC), allowing ceria to release oxygen under reducing conditions and then reversibly take up oxygen under oxidizing conditions, thus making it more effective as compared to irreducible oxides (Al 2 O 3 , SiO 2 ). 11 For Pt supported on ceria (Pt/CeO 2 ) catalysts, CO oxidation reaction has been extensively investigated with respect to the relevant parameters such as size and/or morphology of Pt nanoparticles, 12,13 crystal orientation of CeO 2 support, 14,15 oxygen vacancy concentration at CeO 2 surface, 16 and lattice distortion caused by interaction of the Pt and CeO 2 . 17 Indeed, a rate determining step in CO oxidation reaction has been reported as the reaction of adsorbed CO with oxygen species at the interface between Pt and CeO 2 , not the CO adsorption or the oxygen replenishment at the interface, 13,18 and the corresponding slow reaction step can be affected by both (i) the desorption characteristic of CO on Pt and (ii) the reduction characteristic of O atom at the interface.…”

Oxygen-vacancy-promoted catalytic wet air oxidation of phenol from MnOx–CeO2

“…21 This property of the ceria (110) surface causes the improved catalytic activity for CO oxidation and soot combustion. 22,23 Doping various metals into ceria is another way to create oxygen vacancies. As Mn and Ce have a tendency to form solid solutions, 24,25 doping Mn into the ceria lattice can greatly increase oxygen mobility and also help to produce oxygen vacancies on a catalyst's surface.…”