Monomeric, Two-Dimensionally Ordered WO$_3$ Clusters on Anatase TiO$_2$(101)

TL;DR

This study combines experimental and computational methods to reveal that monomeric WO$_3$ clusters form stable, ordered structures on anatase TiO$_2$(101), providing insights for catalyst design and fundamental surface chemistry.

Contribution

It demonstrates that monomeric WO$_3$ species are more stable than trimers on anatase TiO$_2$(101), and characterizes their geometric structure and ordering.

Findings

Monomeric WO$_3$ are the most stable configuration.

WO$_3$ monomers form tetrahedral WO$_4$ structures.

Ordered (2×1) structures of WO$_3$ monomers are observed.

Abstract

We combined scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS) experiments with density functional theory (DFT) calculations to study dispersed tungsta clusters on anatase TiO$_2$(101). Following two different preparation methods, we found that monomeric WO$_3$ species are the most stable configuration rather than WO$_3$ trimers, (WO$_3$)$_3$. The WO$_3$ monomers form tetrahedral WO$_4$ structures on anatase TiO$_2$(101), with one W$-$O bond and two W$-$O$-$Ti linkages per WO$_3$ monomer. Locally, the WO$_3$ monomers form well-ordered (2$\times$1) structures. The discovered geometric structure of WO$_3$ on anatase TiO$_2$(101) opens up numerous opportunities for fundamental studies addressing tungsta and accurate structure activity studies of WO$_3$/TiO$_2$ model catalysts.