Thermal H2-treatment effects on CO/CO2 conversion over Pd-doped CeO2 comparison with Au and Ag-doped CeO2

Abstract

CO oxidation to CO 2 by Pd-CeO 2 catalysts was tested by temperatureprogrammed mass spectrometry for as-prepared and thermal H 2 -treated Pd-doped CeO 2 catalysts, compared with those of Ag and Au-doped CeO 2 . For the as-prepared samples, the oxidation rate and the T 10 % (the temperature at 10 % CO conversion) occurred in the order of Au & Pd [ Ag ) undoped in the 1st CO oxidation run, while in the 2nd run, the order became Au [ Pd [ Ag ) undoped. For the thermal H 2 -treated samples, the order became Pd [ Au [ Ag [ undoped and Au [ Pd [ Ag [ undoped in the 1st and 2nd CO oxidation runs, respectively. The T 10 % in the 2nd run commonly occurred at much lower temperatures for the metal-doped CeO 2 upon achieving good metal-oxide interfacial contact during the 1st run. The T 10 % of undoped CeO 2 was the most significantly affected by the thermal treatment effects while those of metal-doped CeO 2 catalysts were not greatly affected by the thermal H 2 -treatment. Based on these findings, the metal-support interaction/interface is more important than the surface area, Au (88 m 2 /g) [ Ag (59 m 2 /g) & Pd & undoped.

One-step Synthesis of Ordered Pd@TiO2 Nanofibers Array Film as Outstanding NH3 Gas Sensor at Room Temperature

“…The BET surface areas and the dominated mesopores are 58.8 m 2 ·g −1 and 5.8 nm for pure TiO 2 ; 82.5 m 2 ·g −1 and 12.9 nm for PTND1; 86.7 m 2 ·g −1 and 17.8 nm for PTND2; 100.8 m 2 ·g −1 and 14.8 nm for PTND3; 89.0 m 2 ·g −1 and 14.3 nm for PTND4, respectively. It is shows that the BET surface areas and the dominated mesopores results of Pd@TiO 2 NFs increase significantly than that of pure TiO 2 40 . This illustrates that it is effective to improve cavity and interface structure with the addition of Pd NPs.…”

Liquid-Phase Ethanol Oxidation and Gas-Phase CO Oxidation Reactions over M Doped (M = Ag, Au, Pd, and Ni) and MM′ Codoped CeO2 Nanoparticles

“…CeO 2 catalysts. For undoped Ce oxide, several major peaks (red filled circles) were observed at 2 = 28.5 ∘ , 33.0 ∘ , 47.4 ∘ , 56.3 ∘ , 59.0 ∘ , and 69.3 ∘ , which were assigned to the (111), (200), (220), (311), (222), and (400) planes of the cubic (Fm-3m) structure (JCPDS 034-0394) of CeO 2 , respectively [11,12]. The major peak at 2 = 28.5 ∘ showed no critical difference in peak position for all the samples.…”

“…The hybridization of metal oxides with transition metals has been performed extensively to increase the catalytic (e.g., CO oxidation) efficiency of the oxides [1][2][3][4][5][6][7][8][9][10][11][12]. Among the many metal oxides, a reducible CeO 2 support has been studied extensively as a model oxidation catalyst because of its convertible redox states (Ce 4+ /Ce 3+ ) and oxygen release/storage properties [13][14][15][16][17].…”

Application of Ni-Oxide@TiO2 Core-Shell Structures to Photocatalytic Mixed Dye Degradation, CO Oxidation, and Supercapacitors

“…Figure 8 displays the first and second CO oxidation reaction run profiles. CO 2 (mass = 44 amu) production by CO oxidation was monitored with the increasing reaction temperature by using mass spectrometry [33,53,54,55,56]. Qualitative analysis was performed using the mass profile data.…”