Theoretical study of Au_n clusters (n = 1–5) deposited on a rutile TiO₂ (110) slab, concerning structure and stability

Abstract

The initial nucleation of gold clusters Au n (n = 1-5) on TiO 2 rutile (110) reduced surface is studied using density functional theory and a full-potential augmented-planewave method implemented in the WIEN2k code. The first two gold atoms remained tied to the surface with a bond length similar to those belonging to other well-known related materials, while the other gold atoms do not spread over the surface; they preferred to form a new layer. The occurrence of relativistic effects produced a preferential triangle geometry for Au 3 and a combination of triangular units for Au 4 and Au 5. The Au-Au average distance increased from n = 2 to n = 5, indicating an expansion with a tendency to the bond distance found in the bulk. We are reporting an early 2D!3D transition of small folding, from Au 3 !Au 4 , followed by an Au 4 !Au 5 transition of evident 3D character.

TiO2 Polarons in the Time Domain: Implications for Photocatalysis

“…45 , 46 Whether polarons transfer to metal clusters appears to depend on the sample reduction level and cluster size. 47 − 49 In a 2PPE study of Ag nanoparticles (NP) on rutile TiO 2 (110), Tan et al reported the quenching of the t 2 g → t 2 g feature despite their calculations showing that charge transfer occurred to the substrate. 50 They noted that at this interface, the 2PPE spectra were dominated by plasmonic modes and an “induced interface state”.…”

Heterostructured Photocatalytic Fabric Composed of Ag3PO4 Nanoparticle-Decorated NH2-MIL-88B (Co/Fe) Crystalline Wires for Rhodamine B Adsorption and Degradation

“…29,47 The average bond length of Co−O (2.08 Å) is larger than that of Fe−O (1.72 Å); when a heterogeneous metal is incorporated in NH 2 -MIL-88B, crystalline regularity is disrupted to produce pore defects in their crystal structure, collapsing the micropores (<2 nm). 48,49 Table 1 shows a significant increase in the pore diameter of MIL x @C and Ag/MIL x @C, as the Co/Fe molar ratio was 0− 0.2, supporting the occurrence of pore defects. Eventually, the crystalline defects and pore collapse can be advantageous for adsorption of relatively large molecules like RhB.…”

“…As the Co/Fe molar ratio increased from 0 to 0.2, specific surface area to mass was decreased for MIL x @C and Ag/MIL x @C, probably due to the pore defects created in the nanocrystals of bimetallic MOF. In Figure S4 of the XRD analysis, as the Co/Fe molar ratio increased from 0 to 0.2, the peak area attributed to the (002) crystal plane of NH 2 -MIL-88B decreased, implying the deteriorated crystalline regularity. , The average bond length of Co–O (2.08 Å) is larger than that of Fe–O (1.72 Å); when a heterogeneous metal is incorporated in NH 2 -MIL-88B, crystalline regularity is disrupted to produce pore defects in their crystal structure, collapsing the micropores (<2 nm). , Table shows a significant increase in the pore diameter of MIL x @C and Ag/MIL x @C, as the Co/Fe molar ratio was 0–0.2, supporting the occurrence of pore defects. Eventually, the crystalline defects and pore collapse can be advantageous for adsorption of relatively large molecules like RhB …”

Understanding the prototype catalyst TiO2 surface with the help of density functional theory calculation

“…Au 5 transition of evident 3D character. 60 Au 9 clusters prefer to deposit on the anatase (001) surface at the O 2c O 2c hollow site, 61 and the adsorption energy of the 2D configuration is larger than that of the 3D configuration.…”

“…The structure of Ag 4 is preferred to be tetrahedral on both rutile (110) and anatase (101) surfaces 59 . Regarding the structure of Au n supported on the rutile (110) surface, Agacino Valdes et al reported an early 2D → 3D transition of small folding from Au 3 → Au 4 , followed by an Au 4 → Au 5 transition of evident 3D character 60 . Au 9 clusters prefer to deposit on the anatase (001) surface at the O 2c O 2c hollow site, 61 and the adsorption energy of the 2D configuration is larger than that of the 3D configuration.…”