Zan Dai

Modification with Metallic Bismuth as Efficient Strategy for the Promotion of Photocatalysis: The Case of Bismuth Phosphate

A BiPO4 nanostructure modified with Bi nanoparticles rich in oxygen vacancies in the surface and subsurface was prepared through a one-pot solvothermal treatment utilizing the weak reductive ability of ethylene glycol (EG). The presence of Bi nanocrystals and oxygen vacancies is beneficial for the separation and consumption of photogenerated electrons and holes where Bi nanocrystals act as active sites for the formation of (.) OH and oxygen vacancies are active sites for (.) O2 (-) formation. The enhanced photocatalytic activity is ascribed to the synergistic effect of Bi nanocrystals and surface oxygen vacancies.

Ag-decorated Bi2O3 nanospheres with enhanced visible-light-driven photocatalytic activities for water treatment

Uniform Ag/Bi2O3 nanocomposites with different amounts of Ag were prepared via the deposition precipitation method. Compared with Bi2O3 nanosphere supporters, Ag/Bi2O3 nanocomposites exhibit highly enhanced visible-light-driven Cr(VI) photoreduction activity and photocatalytic bacteria inactivation. Accordingly, the effects that influence the photocatalytic activity of Ag/Bi2O3 nanocomposites were investigated through analyzing its optical properties, photoluminescence, and production of reactive oxygen species (ROS). It was found that the decorated Ag nanoparticles could improve the visible-light adsorption, electron–hole separation efficiency, surface oxygen vacancies and the production of reactive oxygen species of Ag/Bi2O3 nanocomposites, resulting in enhanced photocatalytic performance. This study not only demonstrates that Ag/Bi2O3 could be a promising visible-light-response photocatalyst for water treatment, but it also provides an ideal strategy for improving photocatalytic performance under visible light irradiation.

Generation of defect clusters for 1O2 production for molecular oxygen activation in photocatalysis

Defect engineering on a semiconductor surface can provide coordinatively unsaturated sites for molecular oxygen activation in photocatalysis. In this work, we demonstrated that the vacancy type was key to modulate the molecular oxygen activation process on BiOBr nanosheets. By regulating the reaction time, an oxygen vacancy , a double atom defect cluster and triple atom clusters were accordingly generated on the surface, subsurface and bulk of BiOBr. More importantly, the newly-discovered defect cluster was highly related to the singlet oxygen (1O2) production ability of BiOBr. Meanwhile, the excellent photocatalytic selective oxidation reactions were successfully realized over BiOBr with the defect cluster. In addition, time-dependent defect cluster generation and the associated molecular oxygen activation were discussed.