Microwave-assisted synthesis of oxygen vacancy associated TiO2 for efficient photocatalytic nitrate reduction

The solar-driven photocatalytic technology has shown great potential in nitrate (NO3−) pollutants reduction, however, it has been greatly hindered by the complex preparation and high cost of photocatalysts. Herein, a relatively low-cost photocatalyst, rutile and anatase mixed phase TiO2 was synthesized by a facile microwave-hydrothermal method. Meanwhile, oxygen vacancy is successfully generated, leading to an acidic surface for strong adsorption towards NO3−, which further improved the reduction activity. Compared with the commercial P25, a higher NO3− conversion of ca. 100% and nitrogen (N2) selectivity of 87% were achieved under UV (365 nm) irradiation within 2 h. This research provides a promising strategy for designing efficient noble metal free photocatalyst in the NO3− reduction.