Synthesis of carbon doped WO3·0.33H2O hierarchical photocatalyst with improved photocatalytic activity

A carbon doping method is developed to overcome the drawback of conventional carbon doping method. The carbon dopant is synthesized by treating carbon with dilute nitric acid through hydrothermal process. Carbon-doped WO 3 ·0.33H 2 O (C WO 3 ·0.33H 2 O) is obtained by adding the carbon dopant solution, and then through an additional hydrothermal process. Based on XRD, Raman and XPS, carbon have been incorporated into the interstitial position of WO 3 ·0.33H 2 O unit cell rather than substitution of oxygen in lattice of WO 3 ·0.33H 2 O, which induces distortion of WO 6 octahedron and lattice defect. In addition, carbon doping also induces the emergence of new level above the valence band. The new level increases the migration pathway of photo-generated carriers, which reduces the recombination rate of photo-generated carriers. The changes of band structure, distortion of WO 6 octahedron and lattice defect are beneficial to improve the photocatalytic performance of WO 3 ·0.33H 2 O. Compared with pristine WO 3 ·0.33H 2 O, C WO 3 ·0.33H 2 O display better photocatalytic performance on degradation of rhodamine B (RhB), which include the faster de-ethylation process and cycloreversion process. Moreover, the experiments of radical quenchers confirmed that the h + display the main influence on degradation of RhB. This study implies that carbon can be doped into some metal oxide hydrates through a mild preparation process, which provides a possible way for the synthesis of carbon doped thermal unstable materials.