Low-temperature fabrication of brown TiO2 with enhanced photocatalytic activities under visible light

TL;DR

This paper presents a simple low-temperature method to modify TiO2 with NaH, creating brown TiO2 with oxygen vacancies and Ti(III), which shows significantly improved photocatalytic activity under visible light for organic degradation.

Contribution

A novel, safe, and cost-effective one-step low-temperature process to produce visible-light-active TiO2 with enhanced photocatalytic properties.

Findings

Bandgap shifted to visible spectrum

Enhanced photocatalytic degradation under visible light

Method is scalable and economically advantageous

Abstract

Titanium dioxide is a photocatalytic substance of great practical importance. However, with its bandgap in the ultraviolet (UV) regime, native forms (undoped) of TiO2 generally exhibits poor photocatalytic activities under visible light. Here we report a facile one-step low-temperature method to treat native TiO2 with NaH in a solution-based protocol. The NaH treatment effectively induces the Ti(III) species and oxygen vacancies into the TiO2 host lattice, and enables the bandgap of TiO2 to be conveniently adjusted from the UV region to the red end of the visible spectrum. The modified TiO2 exhibited significantly enhanced photocatalytic capability under visible light, and lead to faster photo-degradation of organic chemical material. Compared with other ways to reduce the bandgap of TiO2, the approach reported here provides unique advantages for safe, large-scale and economic production of narrow-bandgap TiO2 materials.