Yan Sang,Xi Cao,Guangdong Dai,Lvxuan Wang,Yin Peng,Baoyou Geng
The construction of heterojunction system can promote the separation and transfer of photogenerated electron-hole pairs, which is conducive to the degradation of sewage. In this paper, heterostructured Bi 2 O 3 /Bi 2 S 3 nanoflowers are fabricated by a one-step hydrothermal method. The microstructure and optical absorption properties are studied through the detailed characterization of this heterojunction. The visible light photocatalytic ability of as-prepared Bi 2 O 3 /Bi 2 S 3 heterojunctions are investigated by photocatalytic removals of RhB and Cr(VI). The results of photocatalysis indicate that removal efficiencies of RhB and Cr(VI) over Bi 2 O 3 /Bi 2 S 3 heterojunction are higher than those of pure Bi 2 O 3 and Bi 2 S 3 . The improved photocatalytic performance of the Bi 2 O 3 /Bi 2 S 3 heterojunctions could be attributed to a combination of the p-n junction between the p-type Bi 2 S 3 and n-type Bi 2 O 3 , and large specific surface areas (46.31 m 2 g −1 ). Moreover, the probable photocatalytic mechanism of composite photocatalysts is explored in detail by active species trapping experiments, N 2 adsorption–desorption, the transient photovoltage electrochemical impedance spectroscopy and photoluminescence measurements. This work provides new insights into building of the efficient and novel heterogeneous photocatalysts and other energy-related devices.
Yan Sang,Jingwei Xue,Junjie Hu,Peng Zhang,Fugang Zhao,Yanping He
High-low heterojunctions derived from metal-organic frameworks (MOFs) have promising applications in photocatalytic wastewater treatment because of their high photo-redox ability and boosted charge separation efficiency. Herein, Bi-MOF derived porous hierarchical Bi 2 O 3 /Bi 2 S 3 nanoflower-like heterojunctions were prepared by the calcination-hydrothermal method. The optimized Bi 2 O 3 /Bi 2 S 3 -2 composite showed a higher degradation rate of Cr (VI) (99.79 % in 30 min) than the pure substance. Moreover, comprehensive studies were conducted on the kinetics, stability and recycling of Bi 2 O 3 /Bi 2 S 3 , as well as optical characteristics . The active species trapping experiments confirmed that e - plays a dominant role in the elimination of Cr (VI). These findings provided novel strategies for construction of porous hierarchical heterojunctions with advanced visible-light-induced degradation performance. The enhanced photo-degradation efficiency of the optimal nanocomposite was assigned to the higher visible-light absorbance, separation of photogenerated carriers, reduced recombination of photo-induced carriers, and enhanced redox capability owing to the construction of porous hierarchical heterojunctions amongst the components.
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