Solid-state Chemical Synthesis And Photocatalytic Property Of Bi₂O₂CO₃ Nanomaterials

The photocatalytic technology is regared as a green environmental strategy which can directly oxidize organic contaminants to carbon dioxide,water and inorganic acid by chemical oxidation method.There are advantages of fast degradation rate,no selectivity and complete degradation of pollutants for photocatalytic technology.At present,most of work studied on TiO₂ and other oxides.Sulfide and silver-based material has also attracted the attention of researchers.These developed photocatalysts have the disadvantages of low utilization for solar light and light corrosion.Therefore,the development of new photocatalyst is still the hotspot of research.As the Aurivillius photocatalytic compounds,Bi₂O₂CO₃ with the distortion of layered structure which provide unhindered transfer path for photogenerated electrons and holes,thus exhibite excellent catalytic activity.Some methods have been reported to prepare Bi₂O₂CO₃,such as hydrothermal method,microwave-assisted solution method.As far as we know,there is no systematic report on the solid-state synthesis of Bi₂O₂CO₃ by a lowheating solid-state reaction.In this paper,the plate-like Bi₂O₂CO₃ nanomaterial and Bi₂O₃/Bi₂O₂CO₃,Bi OCl/Bi₂O₂CO₃ and Bi OBr/Bi₂O₂CO₃ nanocomposites were simply synthesized by a green solid-state chemical reaction route.The photocatalytic properties of the as-prepared samples were investigated by degradating simulated dyes under UV and visible light irradiation.The photocatalytic mechanism of these materials was speculated through the investigation of the active species in the photocatalytic reaction process.?1?The Bi₂O₂CO₃ nanomaterials were synthesized by solid-state chemical reaction between different bismuth salts and carbonates at room temperature and the optimum reaction system and conditions was determined.The photocatalytic activity of Bi₂O₂CO₃ was studied using RhB,MO,MB and AF as the simulated pollutant.Results showed that Bi₂O₂CO₃ can degrade four kinds of dyes after 30 min irradiation under UV light,especially for RhB,the degradation rates was 100%.The microenvironment of solid-state synthesis has been changed by adding different surfactants which made the size of nanoplates larger and thinner than before.The nanomaterial showed higher catalytic activity in decomposing RhB which can achieve complete degradation after 24 min under UV light.?2?In order to further improve the catalytic performance of Bi₂O₂CO₃,the Bi₂O₃/Bi₂O₂CO₃ composite materials were synthesized through the calcining process of Bi₂O₂CO₃ which was prepared by room temperature solid-state chemical reaction.The introduction of ?-Bi₂O₃ made the light absorption of Bi₂O₂CO₃ extend from ultraviolet light to visible light.Methyl orange can be degradated completely by Bi₂O₃/Bi₂O₂CO₃ composite under visible light irradiation within 180 min.The photocatalytic degradation efficiency of composite was significantly higher than that of Bi₂O₂CO₃.The ·O2-was the major active species during the process of photodegradation.?3?The BiOCl/Bi₂O₂CO₃ and BiOBr/Bi₂O₂CO₃ nanocomposites were fabricated by solid state chemical reaction between bismuth nitrate,sodium bicarbonate and sodium chloride or cetyltrimethylammonium bromide?CTAB?.The CTAB plays a dual role which acted as reactants and template in the synthesis process of Bi OBr/Bi₂O₂CO₃ nanocomposite.The as-synthesized composites exhibited excellent photocatalytic properties for degradation of Rh B that can be completely degraded after 60 min irradiation under visible light,and its photocatalytic efficiency is 188 times of single Bi₂O₂CO₃ because dye sensitization plays a major role in the photocatalytic process.The BiOBr/Bi₂O₂CO₃ nanocomposite have good photocatalytic activity for Rh B which can be completely degraded under visible light irradiation after 60 min,the degradation rated was 25 times of Bi₂O₂CO₃.