Modifying ceria (111) with a TiO2 nanocluster for enhanced reactivity

Abstract

Modification of ceria catalysts is of great interest for oxidation reactions such as oxidative dehydrogenation of alcohols. Improving the reactivity of ceria based catalysts for these reactions means that they can be run at lower temperatures and density functional theory (DFT) simulations of new structures and compositions are proving valuable in the development of these catalysts. In this paper, we have used DFT+U (DFT corrected for on-site Coulomb interactions) to examine the reactivity of a novel modification of ceria, namely, modifying with TiO2, using the example of a Ti2O4 species adsorbed on the ceria (111) surface. The oxygen vacancy formation energy in the Ti2O4–CeO2 system is significantly reduced over the bare ceria surfaces, which together with previous work on ceria-titania indicates that the presence of the interface favours oxygen vacancy formation. The energy gain upon hydrogenation of the catalyst, which is the rate determining step in oxidative dehydrogenation, further points to the improved oxidation power of this catalyst structure.

Titanium Dioxide as a Catalyst Support in Heterogeneous Catalysis

“…Despite these drawbacks, a number of studies have focused on catalytic reaction with TiO 2 as a support material. The mesoporous TiO 2 of pure anatase phase with sharp pore distribution and large surface area was synthesized to increase the degree of distribution and homogeneity of immobilized catalyst [39, 40]. The influences of TiO 2 support on heterogeneous catalysts affect electronic effects and bifunctional mechanism [41].…”

“…Among the TiO 2 modifications, anatase is frequently utilized as a catalyst support for metal heterogeneous catalyst due to its high specific surface area and strong interaction with metal nanoparticles [37, 40]. There are only a few studies reporting a rutile catalyst support which resulted in higher catalytic activity compared to anatase, such as the oxidation of toluene, xylene, and benzene over rutile-supported Cu catalyst.…”

Unraveling the structure sensitivity in methanol conversion on CeO2: A DFT+U study

“…Despite all the above and other theoretical works reported in the literature [37][38][39][40][41][42], up to date there is no complete study assessing the selectivity of methanol dehydrogenation on the most representative ceria facets and proving their different behavior as experimentally observed. Herein, we present a thorough mechanistic study on the selective conversion of methanol to formaldehyde and its subsequent conversion to CO. To account for the particular morphology of the three common nanoshapes above, we have studied the three lowest index and energy surfaces (111), (110), and (100) (Fig.…”

Understanding the Photocatalytic Properties of Pt/CeOx/TiO2: Structural Effects on Electronic and Optical Properties

“…In the literature, heterostructures combining these two oxides have become common in the past five years. TiO 2 clusters on CeO 2 (111) reduce the vacancy formation energy and enhances the oxidation power of this catalytic substrate . However, it is the inverse configuration, CeO 2 on TiO 2 , which has attracted more attention.…”

“…TiO 2 clusters on CeO 2 (111) reduce the vacancy formation energy and enhances the oxidation power of this catalytic substrate. [15] However, it is the inverse configuration, CeO 2 on TiO 2 , which has attracted more attention. Nanoparticles of ceria on a rutile TiO 2 (110) single crystal or on anatase powders exhibit unique structural and electronic properties not seen for bulk ceria.…”