Synchronical pollutant degradation and H2 production on a Ti3+-doped TiO2 visible photocatalyst with dominant (0 0 1) facets

In situ Ti3+-doped TiO2 crystal in mesoporous nanosheets with dominant (0 0 1) facets was prepared by supercritical treatment of the precursor obtained from sol–gel hydrolysis of mixed Ti(n-OC4H9)4 and TiF4. This photocatalyst exhibited high activity in synchronical pollutant degradation and water splitting to produce H2 under visible light irradiation owing to synergistic promoting effects. On one hand, the narrowed energy band gap resulted from Ti3+-doping and the high surface area enhanced light harvest and reactant adsorption. On the other hand, the high crystallization degree accelerated electron transfer and thus, inhibited photoelectron–hole recombination. Furthermore, the exposed (0 0 1) facets with high surface energy favored the activation of reactant molecules. The photocatalytic degradation of organic pollutants promoted the H2 production by consuming photogenerated holes, which inhibited their recombination with photoelectrons used for reducing H+ during water splitting.

Graphical abstractAn in situ Ti3+-doped single-crystal TiO2 in mesoporous nanosheets with exposed (0 0 1) facets was synthesized via supercritical technology, which served as a visible photocatalyst in synchronical degradation of organic pollutants and water splitting to produce H2. The high activity could be attributed to the enhanced light harvesting, facilitated adsorption and diffusion of reactants, and low recombination rate between photoelectrons and holes. Meanwhile, the photodegradation of organic compounds promoted the H2 evolution from water splitting by capturing photogenerated holes.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Preparation of photocatalyst under supercritical conditions. ► Single-crystal TiO2 in mesoporous nanosheets with dominant (0 0 1) facets. ► In situ Ti3+-doped TiO2 visible photocatalyst. ► Synchronical pollutant degradation and H2 production. ► Synergistic effect between photocatalytic oxidation and reduction.