Study On The Preparation Of Bi-based Photocatalysts And Their Elimination Performance Of Organic Pollutants

The organic waste water has the characteristics of chroma,high toxicity and hard-to-degrade in the process of modern production,which do harm to the environment.Photocatalysis,a environmental friendly way to solve environmental pollution and energy crisis,can mineralize organics into non-toxic small molecules with solar energy.In addition,the core of this technology is photocatalyst.Compared with semiconductor photocatalysts such as zinc oxide?Zn O?and titanium dioxide?TiO₂?,bismuth photocatalysts have good photocatalytic performance under visible light due to their unique band structure and moderate band gap.Meanwhile,it has attracted much attention owe to the advantages such as low price,stable structure,and environmentally friendly.Bismuth molybdate?Bi₂MoO₆?and bismuth tantalate?Bi₃TaO₇?are two kinds of Bi based semiconductor photocatalysis materials.In this paper,Ultra-thin structure and semiconductor composite are constructed to obtain efficient photocatalytic materials by promotting the transfer of photocarriers and enhancing the absorption of visible light.Xe lamp is used as visible light source,methylene blue?MB?or other dye solutions such as methyl orange?MO?,Rhodamine B?RhB?,phenol?Phend?are used to simulate dye wastewater,so as to evaluate the photocatalytic performance of the catalyst,elucidate the conversion of organic pollutants by photocatalysis,explore the relationship and mechanism of electronic structure and"active species"of the material and analyze the relationship between the microstructure and the photoelectric properties of the catalyst.The main research contents are as follows:?1?The ultrathin Bi₂MoO₆ nanosheets were synthesized by hydrothermal method by adding surfactant cetyltrimethylammonium bromide?CTAB?.With the average thickness of the Ultra-thin Bi₂MoO₆ nanoflakes reduced to the atomic size?1.6 nm?,oxygen vacancy will be generated on the surface of the catalyst to promote the charge transfer.and the ultra-thin structure of the catalyst can increase the specific surface area and reactive sites.Additionally,the absorption range of ultra-thin Bi₂MoO₆ nano sheet to visible light is significantly widened,which effectively improves the separation efficiency of photogenerated electron hole pairs,thus enhancing the photocatalytic activity of the catalyst.?2?Titanium carbide?Ti₃C₂?was synthesized by etching titanium aluminum carbide?Ti₃AlC₂?with hydrofluoric acid?HF?,and supported on Bi₃TaO₇ to synthesize Bi₃TaO₇/Ti₃C₂heterojunction photocatalyst by hydrothermal reaction.The experimental results show that Bi₃TaO₇/Ti₃C₂ has large specific surface area and suitable light absorption edge.Methylene blue can be completely degraded within 2 hours.And has it good stability?10 cycles?under visible light irradiation.The results of EIS,PL and photocurrent experiments show that the Bi₃TaO₇/Ti₃C₂ heterojunction can enhance the separation of electron hole pairs,the efficiency of electron transport and the ability of interface charge transfer.