| Using solar energy to stimulate semiconductor photocatalyst to decompose organic pollutants effectively at room temperature is considered as one of the most environmentally friendly technologies to solve environmental pollution and energy crisis at the same time.TiO2 photocatalyst can only respond to ultraviolet light,which greatly limits its practical application.For this reason,besides the modification of titanium dioxide,a variety of catalysts with visible light activity have been developed.Among them,bismuth-based semiconductor photocatalysts have been widely studied.Among bismuth-based semiconductor photocatalysts,Bi2O3 has attracted much attention due to its simple composition,non-toxicity,good thermal stability and high soil abundance.However,due to its low photoquantum yield,it is still necessary to further improve its photocatalytic performance.In addition,alkaline bismuth nitrate,the incomplete hydrolysate of Bi?NO3?3·5H2O,has attracted much attention because of its non-toxicity and simple raw materials.However,alkaline bismuth nitrate photocatalyst shows catalytic activity only under ultraviolet light,and can improve its visible photocatalytic activity by compounding with materials with visible light response.In this paper,Bi2O3 and BBN composite photocatalysts modified by carbon and graphite phase carbon nitride?g-C3N4?were prepared and studied.The specific contents are as follows:?1?The complex[Bi6O6?OH?2]?NO3?4·2H2O/g-C3N4?marked as BBN-CN?was prepared by calcining and baking the mixture of Bi?NO3?3·5H2O and g-C3N4 in a muffle furnace.Because of the negative conduction potential of BBN,it is beneficial to the formation of active radical·O2-and the specific surface area of the complex is larger.Under visible light irradiation,the degradation activity of BBN-CN to Rhodamine B?RhB?was better than that of Bi2O3-CN,and BBN-CN had good cyclic stability.?2?Carbon,bismuth metal and bismuth oxide?labeled C/Bi/?-Bi2O3?composites were prepared by calcination in a tubular furnace in nitrogen atmosphere using bismuth citrate as precursor.Surface plasmon resonance effect of bismuth metal and good visible light absorption and conductivity of residual carbon,which makes the photocatalytic activity of?-Bi2O3 better than that of?-Bi2O3 under visible light irradiation.In addition,the temperature at which bismuth citrate decomposes to form?-Bi2O3 is much lower than that at which Bi?NO3?3·5H2O decomposes to form?-Bi2O3.In addition,it was found that the strong chelating effect of EDTA-2Na on Bi3+resulted in the increase of surface negative electricity of?-Bi2O3,?-Bi2O3 and C/Bi/?-Bi2O3 materials,thus enhancing the adsorption capacity of cationic dyes such as malachite green?MG?and methyl violet?MV?. |
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