Direct Imaging of Pt Single Atoms Adsorbed on TiO₂ (110) Surfaces

Abstract

Noble metal nanoparticles (e.g., gold and platinum) supported on TiO2 surfaces are utilized in many technological applications such as heterogeneous catalysts. To fully understand their enhanced catalytic activity, it is essential to unravel the interfacial interaction between the metal atoms and TiO2 surfaces at the level of atomic dimensions. However, it has been extremely difficult to directly characterize the atomic-scale structures that result when individual metal atoms are adsorbed on the TiO2 surfaces. Here, we show direct atomic-resolution images of individual Pt atoms adsorbed on TiO2 (110) surfaces using aberration-corrected scanning transmission electron microscopy. Subangstrom spatial resolution enables us to identify five different Pt atom adsorption sites on the TiO2 (110) surface. Combining this with systematic density functional theory calculations reveals that the most favorable Pt adsorption sites are on vacancy sites of basal oxygen atoms that are located in subsurface positions relative to the top surface bridging oxygen atoms.

Electric field imaging of single atoms

“…The sample preparation is described in detail in the Methods section. The same method has been applied successfully to disperse noble metal single atoms on crystalline and amorphous substrates323334. Figure 4a–c shows simultaneously imaged ADF, electric field vector and strength maps of Au single atoms, respectively.…”

Titanium Dioxide as a Catalyst Support in Heterogeneous Catalysis

“…It is claimed that the enhanced catalytic performance is reflected by a uniform dispersion of Pt nanoparticles and the interaction between Pt and TiO 2 [124]. Thus, the application of Pt as a heterogeneous catalyst becomes more encouraging, especially in electrochemical and photoelectrochemical context [125, 126]. For example, H 2 production could be significantly improved by photocatalytic water splitting over Pt/TiO 2 nanosheets compared to native Pt [126].…”

Pt Nanocluster Co-Catalysts for Photocatalytic Water Splitting

“…Other example of TEM images of Pt atoms show similar structures and measured diameters of less than 0.2 nm [17,18]. The Pt suspension used for impregnation is claimed to produce "Pt clusters" by the manufacturer.…”