Fabrication Of Bi-based Semiconduct Photocatalyst And The Research Of Its Photocatalytic Performance

Preparation of semiconduct photocatalysts with high quality is one of the effective solutions to water pollution.In this article,three kinds of Bi-based photocatalysts,namely Bi₂Cl_xW_1-xO_6-δ（BWOCl）,Bi₂S_3（1-x）W_xO_6-δ（BSWO）,Ag Bi₂Cl_xW_1-xO_6-δ（Ag BWOCl）were synthesized via a facile homogeneous precipitation method.The crystal structures,optical property,and morphology of the products were characterized through a series of experiment technics.And the photocatalytic performance was evaluated through degradation toward Rhodamine B（Rh B）and Methyl Orange（MO）.（1）Different doping ratios of Bi₂Cl_xW_1-xO_6-δphotocatalysts were prepared via a one-step precipitation method with Na₂WO₄·2H₂O,Na Cl,Bi（NO₃）₃ as raw materials and CTAB as surfactant.XRD and other technics were used to characterize the morphology,structure and physical properties of the products.And the Rh B degradation test under visible light was performed to evaluate the photocatalytic performance of catalysts.The result of test exhibits that the optimized composite shows much more excellent photocatalytic performance compared with the undoped ones,with 30 W LED illumination,the degradation rate reached 93.8%,and after 120min,it reached 99.8%.And according to the results of the recycle degradation experiments,photocatalytic performance of the composite maintain robust even after five runs of degradation test,after 5 consecutive degradation experiments,the degradation efficiency could reached 82.2%.Different trapping agents were used to explore the machanism of the degradation reaction.The result suggests that·O₂^-is the major active species during the photocatalytic degradation reaction.（2）A series of Bi₂S_3（1-x）W_xO_6-δcomposites were synthesized through a similar one-step precipitation method with Na₂WO₄·2H₂O,Na₂S·9H₂O,Bi（NO₃）₃ as raw materials,CTAB as surfactant.The crystal structure and morphology of catalyst were also characterized by SEM,XRD technics.The result of photocatalytic performance test suggested that the doped samples exhibited a higher performance than the pristine catalysts,and 98.2%Rh B molecular were decomposed after 2 h under a LED light.The recycle degradation experiment showed that the photocatalytic performance of the catalyst was considerably durable that 65.8%Rh B moleculars were decomposed after 2 h.And the trapping experiments were performed to investigate the active species generated during the photocatalytic degradation process.And its result suggests that·O₂^-is the major active species during the photocatalytic degradation reaction.（3）Ag Bi₂Cl_xW_1-xO_6-δsolid solution photocatalysts were farbricated via a simple one-step precipitation method with Na₂WO₄·2H₂O,Na Cl,Bi（NO₃）₃ and Ag NO₃ as raw materials and CTAB as surfactant.The morphology,crystal structure,chemical composition and optical properties of the products were chacterized through SEM,XRD and other technics.MO was used as model pollutant to perform the degradation experiment.The results of characterization and performance tests suggest that the Ag-doped catalysts possess stronger optical absorbance and improved photocatalytic performance.Compared with Ag-undoped samples,the degradation rate of Ag-doped catalyst could be enhanced from 61.9%to 99.1%with 2 hours LED illumination.Outcomes of cyclic degradation experiments confirmed that the performance of photocatalyst was relatively stable,and 80.1%MO moleculars could be decomposed in the forth recycle experiment.Besides,different trapping agents were used as trapping agents to explore the mechanism of the degradation process.The result exhibits that·O₂^-plays an important role in the process of MO degradation.