Isomerism in Titanium-Oxo Clusters: Molecular Anatase Model with Atomic Structure and Improved Photocatalytic Activity

Abstract

Phase isomerism is a common and important phenomenon in inorganic materials, but the molecular isomerism of their nanocluster models is still rare. In this work, we report the first pair of isomeric titanium-oxo clusters. Through combining pentagonal {Ti(Ti₅ )} building units in corner-sharing or edge-sharing forms, the two obtained Ti₂₀ -oxo clusters take vertical and horizontal core configurations, respectively, which are both functionalized by the same organic ligands. More interestingly, the vertical type Ti₂₀ -oxo core contains an identical {Ti₈ O₁₄ } moiety as anatase, making it the first molecular model of anatase TiO₂ . As a result, the vertical type cluster exhibits better photocatalytic H₂ evolution activity, higher photocurrent response and faster charge transfer to external acceptors than its horizontal isomer. Thus, this work provides a cluster isomer method to understand the structure-property relationship of import titanium oxide materials.

Keywords: cluster compounds; isomerism; photocatalysis; structure-activity relationships; titanium.