Systematic Characterization of Electronic Metal–Support Interactions in Ceria-Supported Pt Particles

Abstract

Electronic metal−support interactions affect the chemical and catalytic properties of metal particles supported on reducible metal oxides, but their characterization is challenging due to the complexity of the electronic structure of these systems. These interactions often involve different states with varying numbers and positions of strongly correlated d or f electrons and the corresponding polarons. In this work, we present an approach to characterize electronic metal− support interactions by means of computationally efficient density functional calculations within the projector augmented wave method. We describe Ce 3+ cations with potentials that include a Ce4f electron in the frozen core, overcoming prevalent convergence and 4f electron localization issues. We systematically explore the stability and chemical properties of different electronic states for a Pt 8 /CeO 2 (111) model system, revealing the predominant effect of electronic metal−support interactions on Pt atoms located directly at the metal−oxide interface. Adsorption energies and the reactivity of these interface Pt atoms vary significantly upon donation of electrons to the oxide support, pointing to a strategy to selectively activate interfacial sites of metal particles supported on reducible metal oxides.

Steam reforming of methane by titanium oxide photocatalysts with hollow spheres

“…Although photocatalysts with a hollow sphere structure efficiently promote water splitting reactions 4,[40][41][42][43][44][45] and CO 2 reduction, 46 the applicability of such catalysts towards photocatalytic SRM remains unclear. Here, hollow sphere-structured TiO 2 was selected as a representative photocatalyst and was loaded with Pt and Rh 2 O 3 as co-catalysts to promote H 2 O reduction and CH 4 oxidation reactions, respectively, because Pt particles in contact with an oxide like CeO 2 have special electronic and chemical properties, 47,48 enabling activation of CH 4 at temperatures below 500 K. 49 To elucidate the photocatalytic SRM reaction mechanism on hollow-structured TiO 2 , the wavelength and temperature dependence of the SRM activity was examined in combination with spectroscopic techniques, including electron-spin resonance (ESR) and photo-luminescence (PL) spectroscopy.…”

Role of Oxidizing Conditions in the Dispersion of Supported Platinum Nanoparticles Explored by Ab Initio Modeling

“…On the other hand, computational studies of Pt nanoparticles are less common in the literature. They usually disregard the support and focus on understanding finite-size effects and establishing d-band correlations for isolated nanoparticles. − Recent works have begun to consider the dynamic structure of Pt nanoparticles supported on metal oxides and exposed to reactants by combining heuristically postulated cluster models, ,− structures resulting from global optimization, , and large nanoparticles derived from bulk or gas-phase structures. − …”

Theoretical study of structure sensitivity on ceria‐supported single platinum atoms and its influence on carbon monoxide adsorption

“…Several DFT studies have reported on the structure and the stability of atomically dispersed Pt on both low‐index and high‐index stepped ceria surfaces 24–30 . Other authors have investigated the interaction of Pt clusters on this support 31–35 . Smaller systems, such as Pt dimers on CeO 2 (111) have been modeled at the DFT + U level.…”