Preparation Of Brookite TiO₂/g-C₃N₄/BiOBr And Photocatalytic Degradation Of Rhodamine B

Photocatalysis has become a research hotspot in the treatment of micro-polluted water because of its advantages of mild reaction conditions,high mineralization rate and no secondary pollution.The photocatalytic activity of brookite TiO₂ is high,but the disadvantages of difficultity to prepare and no absorbtion of visible light limit its development.In this paper,single-phase of brookite was prepared by a hydrothermal method.The composite modification was carried out to broaden the visible light absorption range of brookite and effectively inhibit the photogenerated electron hole recombination.In addition,the degradation for high concentration Rhodamine B by in situ produced H₂O₂ in the electro-Fenton method was studied.The main contents are as follows:（1）Single-phase brookite TiO₂ was prepared by a hydrothermal method.The morphology,conduction band potential and photocurrent curves of the product were analyzed and tested.The photocatalytic degradation for Rhodamine B by the product was also tested.On this basis,the brookite TiO₂/BiOBr heterojunction photocatalyst was prepared by a hydrothermal method.The brookite TiO₂/BiOBr was characterized by XRD,XPS,etc.The influences of composite ratio on the catalytic performance were studied.The results show that the samples of brookite TiO₂/BiOBr（1:0.3）have the best photocatalytic performance with a 99.9%degradation ratio for Rhodamine B under under visible light irradiation for 120 min.（2）Brookite TiO₂/g-C₃N₄/BiOBr composite photocatalyst was prepared by calcination and hydrothermal methods.The products were characterized by XRD,SEM,TEM and XPS.The effects of different composite ratio on the catalytic performance were studied.The results show that TiO₂/g-C₃N₄/BiOBr（1:1:0.6）has the best photocatalytic performance,and its photocurrent is 10 times larger than that of brookite.The degradation ratio for Rhodamine B is 100%under visible light irradiation for 120 min.BiOBr may act as an electron hole bridge in the photocatalytic mechanism of TiO₂/g-C₃N₄/BiOBr.（3）PTFE/nickel foam cathode Fenton material was prepared.The yield of H₂O₂under different conditions and the degradation for rhodamine B with high concentrations were studied.The results show that the H₂O₂ yield on the PTFE/Ni cathode material is 44times higher than that of the foam nickel electrode,and the maximum concentration of H₂O₂ is 2159μmol·L^-1.For 60 min electrolysis,the degradation for 50 mg·L^-1 rhodamine B in the PTFE/Ni system can reach 99.1%.