Theoretical Study of Adsorption of Ag Clusters on the Anatase TiO₂(100) Surface

Abstract

The adsorption of silver atoms, dimers, tetramers, and octamers on the perfect anatase (100) surface has been studied theoretically at density functional theory level. Two complementary approaches based on linear combinations of atom-centered Gaussian-type basis functions and plane waves were applied. The most preferable adsorption positions were found to be hollow sites between two-coordinated oxygen atoms (O(2c)). Adsorption on the Ti–O planes is energetically less favorable. The binding mechanism was interpreted in terms of the interaction between cluster orbitals and orbitals of O(2c) atoms. The charge transfer leads to a deformation of the cluster shape compared with the stable gas-phase structures. In the Ti–O plane sites, an additional binding mechanism exists through the overlap between the silver cluster’s HOMO and unoccupied orbitals of five-coordinated titanium atoms. The same bonding mechanisms have been found previously for the adsorption of Ag particles on the rutile (110) surface1. The growth of silver clusters on the anatase (100) surface via aggregation is an exothermic process and leads to the formation of three-dimensional structures.

A Theoretical Perspective on Charge Separation and Transfer in Metal Oxide Photocatalysts for Water Splitting

“…In 2011, Mazheika et al found that the aggregation of Ag clusters on the (100) surface of anatase TiO 2 is an exothermic process with the use of GGA-PBE method combined with linear combinations of atom-centered Gaussian-type basis functions (LCAO), which results in the formation of three-dimensional clusters. [148] The favorable locations of adsorbed Ag clusters are the hollow sites between two-coordinated oxygen atoms. The adsorbed clusters are positively charged because of charge transfer to oxygen atoms or to unoccupied Ti orbitals.…”

Gold and Silver Clusters on TiO2 and ZrO2 (101) Surfaces: Role of Dispersion Forces

“…73 Moreover, a three-dimensional configuration with tetrahedral shape was reported as the most stable isomer for Ag 4 on a-TiO 2 (100) 73 a-TiO 2 (101) 74 and r-TiO 2 (110) 70 surfaces. However, we have checked this structure and we found that it is unstable on a-TiO 2 (101).…”

Charge Carriers Cascade in a Ternary TiO2/TiO2/ZnS Heterojunction: A DFT Study

“…Several examples of these composites were presented recently, also including titania-based materials. [24][25][26][27] More specifically, titania can be combined with a metal, [28][29][30][31][32][33] graphene, [34,35] or another oxide. [19,20,36,37] Composites can be also created by interfacing two different polymorphs of TiO 2 , [38][39][40][41][42][43] or even two different faces of the same polymorph.…”