Synthesis And Performance Of Bismuth-based Photocatalytic Material

Nowadays,the rapid development of technology brings a lot of convenience to mankind,in the meantime,environmental pollution and energy shortages also follow and have become serious problems that threaten the human survival and development in the future.The emergence of semiconductor photocatalytic technology,including photocatalytic degradation of organic pollutants and photocatalytic water splitting are expected to become effective means to solve these problems.So the development of new semiconductor photocatalyst is of great significance.In this paper,three kinds of semiconductor photocatalytic materials?BiPO₄/WO₃,Bi₂MoO₆/Cu?OH?₂,CdS QDs/Bi₂MoO₆?were prepared,the structure and their corresponding properties were characterized by XRD,SEM and TEM techniques.The photocatalytic performance was evaluated by photocatalytic degradation of the dye and photocatalytic water splitting.The main research contents are as follows:?1?BiPO₄/WO₃ composite photocatalytic materials were successfully synthesized by a hydrothermal method.The photocatalytic performances of the composites with different doping ratios were investigated by photodegradation of simulated wastewater?rhodamine B?.When the molar ratio of BiPO₄ to WO₃ was kept to be 1:2,the as-prepared BiPO₄/WO₃ composite exhibited the highest photocatalytic performance and the degradation efficiency of rhodamine B could reach 77.23% within 2h under 300 W xenon lamp irradiation.The enhanced photocatalytic activity could be ascribed to the matched band structure between BiPO₄ and WO₃,which could not only promote the separation of photogenerated electron-hole pairs,but also extend the absorption range of BiPO₄ to the visible region and consepuently improve the utilization efficiency of photon.The photocatalytic mechanism of the composites was studied by the experiment of the capture of active substance.The results showed that the holes were the main active substance in the photocatalytic degradation of rhodamine B.?2?Using bismuth nitrate and sodium molybdate as raw materials,Bi₂MoO₆ photocatalyst was firstly synthesized at by solvothermal method at 120? for 12 h.After that,Bi2 Mo O6/Cu?OH?₂ composite was synthesized by deposition Cu?OH?₂ onto Bi₂MoO₆ by co-precipitation method.Compared to pure Bi₂MoO₆,the Bi₂MoO₆/Cu?OH?₂ composite exhibited a better photocatalytic performance and the efficiency of hydrogen production of Bi₂MoO₆/Cu?OH?₂ composite reached 451.83 ?molh-1g-1 within 6 h under 300 W xenon lamp irradiation when the amount of Cu?OH?₂ content was kept to be 1%.During the photocatalytic process of Bi₂MoO₆/Cu?OH?₂ composite phtotocatalyst,Cu?OH?₂ as co-catalyst could capture the excited electrons resulted from the Bi₂MoO₆ photocatalyst and promote the separation of electrons and holes,thereby leading to the enhanced photocatalytic performance.?3?CdS QDs/Bi₂MoO₆ composites were prepared in aqueous solution by a mild and simple method under a nitrogen atmosphere using mercaptoacetic acid as stabilizer.The heterojunction structure formed between CdS quantum dots and Bi₂MoO₆ could promote the separation of photo-generated electrons and holes,thus the composites exhibited higher photocatalytic performance than that of pure CdS quantum dots.As the doping amount of Bi₂MoO₆ was set to be 7%,the CdS QDs/Bi₂MoO₆ composites showed the highest photocatalytic activity and the hydrogen production efficiency of could reach 727?molh-1g-1 under the irradiation of 300 W xenon lamp.