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

Abstract

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 WO3·0.33H2O (CWO3·0.33H2O) 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 WO3·0.33H2O unit cell rather than substitution of oxygen in lattice of WO3·0.33H2O, which induces distortion of WO6 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 WO6 octahedron and lattice defect are beneficial to improve the photocatalytic performance of WO3·0.33H2O. Compared with pristine WO3·0.33H2O, CWO3·0.33H2O 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.