Oxygen activation on the interface between Pt nanoparticles and mesoporous defective TiO2 during CO oxidation

Abstract

Platinum-based heterogeneous catalysts are mostly used in various commercial chemical processes because of their high catalytic activity, influenced by the metal/oxide interaction. To design rational catalysts with high performance, it is crucial to understand the relationship between the metal–oxide interface and the reaction pathway. Here, we investigate the role of oxygen defect sites in the reaction mechanism for CO oxidation using Pt nanoparticles supported on mesoporous TiO2 catalysts with oxygen defects. We show an intrinsic correlation between the catalytic reactivity and the local properties of titania with oxygen defects (i.e., Ti3+ sites). In situ infrared spectroscopy observations of the Pt/mesoporous TiO2−x catalyst indicate that an oxygen molecule bond can be activated at the perimeter between the Pt and an oxygen vacancy in TiO2 by neighboring CO molecules on the Pt surface before CO oxidation begins. The proposed reaction pathways for O2 activation at the Pt/TiO2−x interface based on density functional theory confirm our experimental findings. We suggest that this provides valuable insight into the intrinsic origin of the metal/support interaction influenced by the presence of oxygen vacancies, which clarifies the pivotal role played by the support.

Band restructuring of ordered/disordered blue TiO2 for visible light photocatalysis

“…In contrast, in Na-reduction, the Ti 3+ oxidation states emerge from the disordered anatase phase after 7-day reduction, which is consistent with the related Ti2O3 peak in the O 1s spectra (Fig. 3b and inset) [25][26][27]. A similar trend of oxidation state to phase-mixed TiO2 was observed in single-phase rutile and anatase TiO2 study (Fig.…”

Operando Surface Studies on Metal-Oxide Interfaces of Bimetal and Mixed Catalysts

“…Enhancement of catalytic activity for CO oxidation has been studied using interfacial metal-oxide catalysts. The catalytic reaction is widely utilized in automotive catalysis, efficient CO removal in PEMFC, and industrial chemical processes . The metal-oxide supported Au catalyst is a representative example to show an exceptional property of the metal-oxide interface.…”

High Catalytic Activity of Pt/Al2O3 Catalyst in CO Oxidation at Room Temperature—A New Insight into Strong Metal–Support Interactions

“…In addition, a very small peak at 2130 cm −1 was also recorded. This peak is usually assigned to CO adsorption on the oxidized form of platinum atoms [36]. Comparing the peaks areas, it can be stated that the percent concentration of the bridge-bonded CO is ca.…”