Single-stage medium temperature water-gas shift reaction over Pt/ZrO2 – Support structural polymorphism and catalyst deactivation

Relationship between Acid–Base Properties and the Activity of ZrO2‐Based Catalysts for the Cannizzaro Reaction of Pyruvaldehyde to Lactic Acid

“…In the monoclinic crystal phase, the Zr 4+ cations are hepta‐coordinated and the O 2− anions are tri‐ or tetra‐coordinated. On the other hand, in the tetragonal structure, the Zr 4+ cations are octa‐coordinated and the O 2− anions are tetra‐coordinated . Such different coordinations and structural arrangements will generate different types of coordinatively unsaturated surface sites and will consequently lead to quite distinct acid–base surface properties.…”

Review: monoclinic zirconia, its surface sites and their interaction with carbon monoxide

“…This choice is made for simplicity and clarity, as monoclinic and tetragonal zirconias differ in, e.g., surface hydroxyl species 7,25 and acidity/basicity 7,24,30 , further demonstrated in their interactions with CO 7,25,30 and in their catalytic activity, e.g., in water-gas shift 11,12 . More information can also be found in the reviews by Dyrek et al 35 and Hadjiivanov 36 .Most of the pre-1993 works included in this paper were reviewed 20 years ago by Nawrocki et al 37 in the context of chromatography; this review is providing an update with work reported since 1993, from the perspective of catalysis.…”

“…The hydroxyl groups on the surface can be manipulated by thermal treatment in vacuum or in different atmospheres 9 , which are often necessary for catalytic applications, e.g., in methanol synthesis 10 . Additionally, monoclinic zirconia has been suggested as a support for water-gas shift reaction catalysts with gold, platinum and copper [11][12][13] , and for reforming with platinum, nickel, cobalt and copper 14,15 .…”

Highly efficient Au/ZrO2 catalysts for low-temperature water–gas shift reaction: Effect of pre-calcination temperature of ZrO2

“…active sites for the WGS reaction), and that Au nanoparticles supported on monoclinic zirconia exhibited higher WGS activity than that on tetragonal zirconia. Such a ZrO 2 crystal phase effect was also reported with respect to Pt/ZrO 2 WGS catalysts [21]. In our previous work [22], we have shown that Au/ZrO 2 catalyst using hydrothermally synthesized ZrO 2 as support exhibits superior WGS catalytic activity than Au/CeO 2 catalyst and that its high catalytic activity can be ascribed to the uniform nanodisk morphology of ZrO 2 .…”