The Study Of The Dye Adsorption And Photocatalytic Performance For Molybdenum Oxide Layer Material

The rapid development of the current industrial led to a series of problems of environment pollution and energy crisis,semiconductor photocatalyts have aroused wide attention because these photocatalyts not only can directly convert the solar energy into usable or storable energy but also can degrade the stable organic pollutants under solar-light irradiation.However,those applications need photocatalysts with good stability,wide absorption,high electron-hole separation efficiency and maintained strong redox ability.Obviously,it is difficult for single-component catalytic system to fulfill all these requirements aforementioned at the same time.In recent years,the artificial heterogeneous Z-scheme photocatalytic systems which inspired by the natural photosynthesis in green plants have been researched as a popular topic due to its excellent performance,but how to construct Z-scheme photocatalytic systems is still a significant challenge.In this study,we have synthesized MoO₃ nanobelts by hydrothermal method and constructed AgBr/MoO₃ nanocomposites by a simple deposition-precipitation method.The as-prepared AgBr/MoO₃ hybrid materials were characterized by XRD,SEM,TEM,DRS,FT-IR and PL.The adsorption performance of the MoO₃ nanobelts was evaluated using methylene blue as adsorbate and the Rhodamine B was a target organic pollutant to evaluate the photocatalyti activity of the AgBr/MoO₃ nanocomposites.Meanwhile,Material Studio was used as a simulated calculation software to reveal the reaction mechanism.The main research works and results are as follows:（1）The MoO₃ nanobelts were successful synthesized by by hydrothermal method（180 oC / 12 h）,the as-prepared MoO₃ nanobelts showed poor photocatalyti activity for both methylene blue and Rhodamine B due to the wide bandgap of MoO₃,but the MoO₃ nanobelts existed excellent adsorption performance for methylene blue.（2）The maximum adsorption capacity of methylene blue for the as-prepared MoO₃ nanobelts was up to 577 mg g-1,and the adsorption process was in line with the Langmuir adsorption process model;the adsorption rate increased with the temperature rising and remained stable in a wide range of pH;the results showed that the adsorption process was mainly on the surface of MoO₃ due to the electrostatic adsorption.（3）The novel Z-Scheme AgBr/MoO₃ nanocomposites were successfully synthesized through deposition-precipitation method with anhydrous ethanol as the medium,the size of AgBr particles on the MoO₃ nanobelts were ¹0 nm which is mainly caused by directed diffusion of Br-due to charge induction.When the mole ratio of AgBr/MoO₃ nanocomposites was 1:3 degradation efficiency reached the highest,which can decompose 10 mg L-1 rhodamine B within 5 min with the efficiency more than 95 %,and the reaction constant is 0.468 min–1.The AgBr/MoO₃ nanocomposites has strong photocurrent response with the current density up to 1.7 muA cm2,while there is no obvious photocurrent response for pure MoO₃,meanwhile the nterface charge transfer resistance of pure MoO₃ is 2.3 times of AgBr/MoO₃ nanocomposites.The first principles calculation results show that the band gap decreases of AgBr/MoO₃ nanocomposites was due to the orbital hybrid of O 2p and AgBr MoO₃ Br in 4p.The capture experimental results show that the O2-·free radicals were the main reactants during the photocatalysis process and the reactants of De-ethylation process.