Fabrication Of Bismuth-based Photocatalyst And Study On Photodegradation Of Organic Pollutants And Photoelectrochemical Catalytic Properties

Due to the rapid progress of industrialization,the pollutant emission and energy consumption,water pollution and energy shortage have become the urgent problems of human society.Photocatalytic technology,driven by inexhaustible sunlight,has a good application prospect in water pollution treatment and hydrogen production from water decomposition.In this paper,three novel Bi based semiconductor photocatalysts with two-dimensional nanosheets were prepared by a mild one-step precipitation method.The photocatalytic performance of these two-dimensional nanosheets was evaluated,and the catalytic reaction mechanism was explored.Na₂WO₄·2H₂O,Na Br,Bi（NO₃）₃were used as main raw materials and cetyltrimethylammonium bromide（CTAB）was used as structure regulator,a series of BWOBr solid solution photocatalysts with different W:Br ratios were prepared by one-step precipitation method.The crystal structure,morphology,elemental composition and optical properties of the catalyst were characterized by XRD,SEM,TEM,XPS and UV-Vis absorption spectra.The photocatalytic activity of the catalyst was evaluated by photocatalytic degradation of Rhodamine B（Rh B）and photoelectric catalytic performance test.The results showed that when the molar ratio of W to Br was 1:9,the photocatalytic degradation rate of Rh B was 93.2%,which was 2.3 and 2.4 times of that of Bi₂WO₆and Bi OBr in the same time.The photocatalysis test results show that the catalyst has excellent photocatalytic performance for water decomposition.The transient photocurrent test results show that the high separation efficiency of photogenerated electron hole pairs is the reason for its excellent photocatalytic performance.Then,the energy band structure of the catalyst was obtained by using the Mott Schottky curve and UV-Vis absorption spectrum,and the mechanism of photocatalytic degradation and photocatalysis was proposed.Using Na₂WO₄·2H₂O,KI,Bi（NO₃）₃as main raw materials and CTAB as template,BWOI solid solution photocatalysts with different W:I ratios were prepared by one-step precipitation method.The physicochemical properties of the catalyst were characterized by XRD,SEM and XPS.The photocatalytic activity of Rh B was evaluated by the degradation reaction of Rh B.The results showed that when the ratio of w to I was 6:1,the product exhibited the highest photocatalytic activity.The degradation rate of Bi₂WO₆and Bi OI was 2.9 and 5.4 times higher than that of Bi₂WO₆and Bi OI alone.Using LED as light source,the photocurrent response of the catalyst was significantly higher than that of Bi₂WO₆and Bi OI samples at 0 V（vs RHE）.The mechanism of catalytic reaction was explained by free radical trapping experiment,Mott Schottky test and UV-Vis absorption spectrum.Using Na₂WO₄·2H₂O,Na₂S·9H₂O,Ag NO₃and Bi（NO₃）₃as main raw materials and CTAB as template,Ag BWOS photocatalysts with different Ag contents were prepared by one-step precipitation method.XRD,SEM,XPS and UV-Vis absorption spectroscopy were used to characterize the physicochemical properties of the catalyst,such as crystal structure,elemental composition,etc.The results showed that the 0.1Ag-BWOS-9-1 catalyst had the highest photocatalytic degradation and photocatalysis efficiency when the amount of Ag was 0.1 mmol.The results of repeated degradation experiment and chronopotentiometry showed that the catalyst had good stability for the degradation of Rh B 5 times and 12 times After the photocatalysis test within 2 h,the catalyst still keeps high catalytic efficiency.The results of optical characterization and photocurrent measurement show that the high photocatalytic activity of the sample is mainly due to its good absorption characteristics and high efficiency of photogenerated electron hole separation.