Effect of synthesis condition on properties of Ce0.67Zr0.33O2 mixed oxides and its application in Pd-only three-way catalysts

Hydrothermal Synthesis and Catalytic Activity of CeZrAl Oxide-Supported Pd for the Purification of Gasohol Exhaust

“…Pd catalyst supported on CZA synthesized by hydrothermal treatment exhibited higher catalytic activity toward the conversion of C 3 H 8 , CO, and ethanol with T 50 decreased by 50, 15, and 59 C, respectively, compared with those of a catalyst on a support prepared without hydrothermal treatment. The interaction between Pd and CZA-S can result in the appearance of Ce 3C species, which enhance the reaction of NO with CO. Pd supported on CZA with hydrothermal treatment lead to charge transfer from Pd species to Ce, which gives rise to the formation of defect CeO x and more lattice oxygen in the catalyst.…”

“…It maybe attribute to the incorporation of Al 3C into the CZ lattice by replacing of Ce 4C /Ce 3C or Zr 4C . [15] The sharpening of peaks for CZA-H implies the growth of the crystallites and more complete CZ solid solution crystal shape during hydrothermal process, as also proven by the increased crystallite size of CZA listed in Table 1.…”

Catalytic reduction of nitrite in water over ceria- and ceria–zirconia-supported Pd catalysts

“…From these results, the more reduced states on PCZ1 and PCZ2 catalysts might be because of a defect structure induced by the insertion of appropriate amount (x = 0.3 and 0.5) of Zr to the CeO 2 [29,30]. However, the lowest Ce 3+ concentration on PCZ3 catalyst resulted from a high Zr amount (x = 0.7), forming the irreducible structure.…”

“…The band was shifted to higher frequencies and became weaker as the Zr content increased, probably attributed to the distortion of CeO 2 lattice by the displacement of Ce 3+ with Zr 4+ [28,33]. Compared to the Raman spectrum of Pd-free CeO 2 support (data not shown), a very broad band in the range 600-650 cm −1 was observed for the PC catalyst, which was attributed to the formation of oxygen vacancies on the catalyst surface [29,34]. For the catalysts with a composition of 0.3 ≤ x ≤ 0.7, we also found the presence of oxygen vacancies in the spectra, although the band was affected by the growth of the tetragonal phase.…”

“…In contrast, there was no relationship between the Zr content and pore volume. [28,29]. When x increased from 0.3 to 0.7, the tetragonal phase of ZrO 2 appeared in the XRD spectra, whereas the cubic CeO 2 peaks became weaker and broader.…”