Solid-state NMR of active sites in TiO₂ photocatalysis: a critical review

Abstract

Titanium dioxide (TiO₂) is one of the optimal semiconductor metal oxide photocatalysts with a wide range of application fields, such as heterogeneous catalysis, energy science, and environmental science. Solid-state nuclear magnetic resonance (NMR) spectroscopy is a powerful tool for characterizing both structure and dynamics at an atomic-molecular level in heterogeneous catalysts. In this review, we first provide a brief discussion on the progress in investigating the structures of titanium and oxygen in bulk and on the surface of TiO₂ by using various solid-state NMR techniques. Advances in the understanding of electronic structure and properties of TiO₂ with distinct surface features, including various crystal facets and heteroatomic adsorption by chemical probe-assisted NMR techniques, are secondly presented. The solid-state NMR characterization of heteroatom active sites (such as ¹³C, ¹⁵N, ¹¹B, ²⁷Al) and their function in TiO₂ photocatalysts is described in detail. Finally, a critical discourse assesses the current limitations and prospects of solid-state NMR in its application to the optimization and design of advanced TiO₂ photocatalysts.

Keywords

Characterization / solid-state NMR / TiO₂ / photocatalyst / active sites

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