On the adsorption and formation of Pt dimers on the CeO2(111) surface

Abstract

The direct adsorption of Pt(2) dimers on CeO(2)(111) and their formation from isolated adsorbed Pt atoms have been studied using periodic slab model calculations based on density functional theory and including the so-called on-site Hubbard parameter (GGA + U). In the most stable configuration Pt(2) is found to be almost parallel to the surface; the electronic ground state is closed shell and there is no evidence of charge transfer towards or from the surface. The formation of Pt(2) from two single adsorbed Pt atoms involves a rather small energy barrier of ~0.10 eV only. On the contrary, dissociation of adsorbed Pt(2) requires to overcome a considerable barrier of ~1.43 eV. This indicates that once Pt(2) is formed it will remain on the surface, thus likely triggering the growth of larger supported Pt particles.

The surface chemistry of cerium oxide

“…Cu [245][246][247][254][255][256], Ni [254], Pd [239,[257][258][259], Pt [258,[260][261][262] and Rh [258,259,263]. The adsorption of single metal atoms has generally found an affinity between the admetal and surface O with a preference for adsorption in the CeO 2 (111) Further, the ability of the ceria substrate to donate O to the CO was inhibited by annealing the ceria to elevated temperatures.…”

Towards stable single-atom catalysts: strong binding of atomically dispersed transition metals on the surface of nanostructured ceria

“…A similar situation takes place on the most stable (111) surface of CeO 2 , a reducible oxide support widely used in catalysis. 14 This indicates that the formation of transition metal SACs that are sufficiently stable to counteract metal-metal bond formation upon sintering requires special strongly binding sites on the supports.…”

Maximum Noble‐Metal Efficiency in Catalytic Materials: Atomically Dispersed Surface Platinum

“…If this was the case, the Pt 2+ would easily be covered by coexisting metallic Pt. To answer this question we investigate the formation of Pt 2 dimers, which is strongly exothermic (369 kJ mol À1 ) [20] on regular CeO 2 (111). In sharp contrast, the anchored Pt 2+ does not favor bond formation with another Pt atom.…”