Effects of CeO2-ZrO2 present in Pd/Al2O3 catalysts on the redox behavior of PdOx and their combustion activity

Pd catalysts for total oxidation of methane: Support effects

“…We measured the dispersion of only one of our two ceria-supported catalysts; it displayed the lowest dispersion within the sample set. Others have observed a dependence of Pd dispersion on support composition [12,20]. Even within cerias, Pd dispersion has been observed to depend on the details of support morphology and chemistry.…”

“…The activity of the catalyst depends on a number of factors, but the density and activity of site pairs are among the most important [6,7]. These characteristics are functions of the size, morphology and surface chemistry of PdO crystallites that reside on the support surface, which in turn depend on the details of catalyst preparation [6,[8][9][10][11], operating conditions [10] and, significantly, the interactions of PdO with its support [7,[12][13][14][15]. Different supports can stabilize PdO crystallites in different sizes and morphologies [16].…”

Pd catalyst supported on ZrO2‐Al2O3 by double‐solvent method for methane oxidation under lean conditions

“…Generally, the apparent contrast of Zr-Al and active component Pd particles in TEM images were different, and the mostly black dots in the image were caused by Pd particles. [6,[31][32][33][34] In our TEM images, the average particle size of Pd particles were about 60-100 Å, as signed by the white arrows in Figure 1. The results accorded with those of CO chemisorption well (Table 1).…”

“…[18] This suggested that the reduction of PdO formed on the supports could take place even before room temperature. [6,34] In the work by Zhou R. X. et al, [34,39] the H 2 -TPR experiment was conducted under the condition that all samples were pre-cooled at -20 °C in air and then heated to 800 °C in a…”

Hydrogen Production by Methanol Steam Reforming Over Pd/ZrO2–TiO2 Catalysts

“…This peak was attributed to reduction of big PdO particles at the surface to Pd 0 [30,31]. Zhou et al [32] observed that palladium oxide supported on Al 2 O 3 is easily reduced near to 11°C representing the reduction of PdO species highly dispersed on Al 2 O 3 , and a negative peak at about 90°C which was attributed to the decomposition of palladium hydride. Two tiny reduction peaks on the Pd/ZrO 2 sample were observed, and they correspond at the reduction of some fraction of the PdO at 40 and 95°C respectively.…”