Preparation Of Hierarchical Porous Structures Bi₂O₃ – Based Nanocomposites And Their Photocatalytic Property

In recent years,water and pollution of the ecological environment are increasingly polluted by antibiotics and is now one of the most concerned environmental issues for environmental scientist.Among them,tetracycline has become one of the main pollutants for environmental pollution of antibiotic-like substances.Photocatalytic technology can efficiently treat refractory organic wastewater,and no secondary pollution,low energy consumption.Under visible light irradiation conditions to complete degradation of the target contaminant.At present,the biological template method is the most direct and effective research method for material morphology and structure control in the field of inorganic material preparation.In this article uses sunflower stalk as a template,preparation of Bi2O3-based nanocomposites,and the composition,morphology,structure properties of the materials were analyzed by series of characterization methods,and tetracycline as the target pollutant was used to investigate the catalytic activity and stability of each material.Provide theoretical basis and technical support for the development of economical and efficient antibiotic wastewater that hard to degrade treatment technology.In this research,Hierarchical porous Bi2O3 nanomaterial was prepared using sunflower stalk as biological template via high temperature calcination.Next,hydrothermal method using Bi2WO6 and La Fe O3 form a composite catalytic material Bi2WO6/Bi2O3 and La Fe O3/Bi2O3.The catalytic materials were analyzed by X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),X-ray photoelectron spectroscopy(XPS),UV-visible diffuse reflectance(UV-vis)and Photoluminescence(PL).The results show that the sample prepared by high temperature calcination is monoclinic phase ?-Bi2O3 with sunflower stalk biological template completely removed.The surface of Bi2O3 samples show granular structure and is formed by the interconnection of porous channels to form a porous honeycomb structure.Bi2WO6 is globularly attached to the surface of Bi2O3 to form Bi2WO6/Bi2O3 composite;La Fe O3 is attached to the surface of Bi2O3 in a small spherical shape to form La Fe O3/Bi2O3 composite.Using Xenon lamp(150W,400~800nm)as the light source,Tetracycline was used as photocatalytic degradation pollutant to evaluate the photocatalytic performance of the composite catalytic material,and the reaction mechanism was analyzed.The results show that the Bi2WO6/Bi2O3 and La Fe O3/Bi2O3 composite exhibits better catalytic activity for Tetracycline under visible light than pure phase Bi2O3.The degradation rates of Bi2WO6/Bi2O3 and La Fe O3/Bi2O3 prepared by template method for 20mg/L tetracycline were 99.1% and 99.5%,respectively.The photocatalytic activity of composite photocatalytic materials is best when the doping ratio of Bi2WO6/Bi2O3 and La Fe O3/Bi2O3 are both 1:2.And the degradation effect is best when the solution p H=6 and the compound photocatalytic material dosage is 0.4g.The photocatalytic activity of the composite catalyst is mainly due to the formation of heterojunctions in Bi2WO6 and Bi2O3 and the formation of heterojunctions in La Fe O3 and Bi2O3,which improve the separation efficiency of the photogenerated electron-hole pairs.Comparing the doping of two kinds of materials to improve the photocatalytic performance of Bi2O3,La Fe O3 can improve the photocatalytic performance of Bi2O3 more significantly.