Facilitated vacancy formation at Zr-doped ceria(111) surfaces

Direct CO Oxidation by Lattice Oxygen on Zr-Doped Ceria Surfaces

“…1a (111) efficiently attract CO molecules from the gas phase, as suggested by the sizable adsorption energy of 18.5 kcal/ mol. On the other hand, Zr dopants reduce the energy cost for the formation of oxygen vacancy [4,29] and thus increase the mobility of lattice oxygen atoms nearby [30]. If we define the formation energy of an O vacancy as:…”

“…, which releases stress for the creation of Ce 3? ; (2) the smaller reduction energy [4,29]; and (3) the higher oxygen mobility of the Zr-doped ceria as compared with the pure ceria [30]. Since the binding energies of CO are rather high on the clean and Zr-doped CeO 2 (110), the reaction can be easily poisoned and the (110) surfaces remain inactive.…”

Oxygen vacancy formation on the Ni/Ce0.75Zr0.25O2(111) surface. A DFT+U study

“…3 for O1 vacancy location). This oxygen has been selected because of its location near to a Zr cation, which is known for its anion vacancy formation promoter effect [7]. Fig.…”

“…This characteristic is originated in the Ce cations reduction facility, which is mainly related to the formation of Ce 4þ /Ce 3þ couples and oxygen release/storage capacity (OSC) [5]. CeO 2 performance is enhanced by the addition of transition, alkaline earth or rareearth metals [6,7]. Particularly, the doping with Zr results in better redox properties, oxygen storage capacity, thermal resistance and catalytic activity [8e13].…”

“…Among the benefits of using CeO 2 eZrO 2 mixed oxides as support we can mention their ability to effectively disperse Ni, which results in a better resistance to poisoning by carbon deposition [16]. The presence of Zr 4þ cations substantially diminishes the energy necessary for Ce 4þ to Ce 3þ reduction and facilitates the formation of anionic defects in CeO 2 [7,17,18].…”