A three-dimensional nano-network WO(3)/F-TiO(2)-{001} heterojunction constructed with OH-TiOF(2) as the precursor and its efficient degradation of methylene blue

In this study, three-dimensional nested WO(3)/F-TiO(2)-{001} photocatalysts with different WO(3) loadings were prepared by a hydrothermal process and used to degrade methylene blue (MB). The photocatalysts with various ratios of WO(3) to OH-TiOF(2) can be transformed into a three-dimensional network WO(3)/F-TiO(2) hetero-structure with {001} surface exposure. The results showed that the composite catalyst with 5% WO(3), denoted as FWT5, had the best comprehensive degradation effect. FWT5 has a limited band gap of 2.9 eV, which can be used as an advanced photocatalyst to respond to sunlight and degrade MB. The average pore diameter of the composite catalyst is 10.3 nm, and the multi-point specific surface area is 56 m(2) g(−1). Compared with pure TiOF(2), the average pore size of the composite catalyst decreased by 8.44 nm and the specific surface area increased by 51.2 m(2) g(−1), which provides a larger contact space for the catalytic components and pollutants. Moreover, TiO(2) on the {001} surface has higher photocatalytic activity and methylene blue can be better degraded. Under the irradiation of 0.03 g FWT5 composite catalyst with a simulated solar light source for 2 h, the degradation rate of 10 mg L(−1) methylene blue can reach 82.9%. The trapping experiment showed that photo-generated holes were the principal functional component of WO(3)/F-TiO(2)-{001} photo-catalysis, which could capture OH(−) and form hydroxyl radical (˙OH) and improved the photocatalytic degradation performance. Kinetic studies show that the photocatalytic degradation of MB fits with the quasi-first order kinetic model.