Preparation And Research Of Photocatalytic Performance Of SnO₂/TiO₂ And GO Doped Composite Materials

In recent years,water pollution has become more and more serious,and the preparation and performance of TiO₂,SnO₂ and graphene oxide doped materials have been paid more and more attention by researchers.In this paper,composite materials were prepared by two methods.SnO₂-TiO₂ composite semiconductor photocatalysts were prepared by one-step sol-gel method and SnO₂/TiO₂ composite semiconductor photocatalysts were prepared by stepwise method.The structures and properties of the samples were characterized by XRD,SEM,FTIR and UV-Vis DRS absorption.Rhodamine B was used as a simulated contaminant to select the catalyst with good photocatalytic performance.Finally,the photocatalysts of SnO₂/TiO₂/GO composites were prepared and characterized by SnO₂/TiO₂ composite semiconductors further modified by graphene oxide.The details are as follows:?1?Orthogonal experiments were carried out to prepare nano-SnO₂-TiO₂ composite semiconductor photocatalyst by sol-gel method using butyl titanate and tin tetrachloride as the precursors,glacial acetic acid as chelating agent and anhydrous ethanol as dispersant.The optimum conditions : the molar ration of SnO₂ and TiO₂ was 1: 8,the volume ratio of ethanol and water 1: 2 and the calcination temperature 400 ?.The characterization results showed that SnO₂-TiO₂ compound semiconductor photocatalyst after calcination was mainly anatase crystal shape,spherical with about 12.6 nm of diameter,which had the ability to responsive to visible light.The results of photocatalysis showed that the efficiency of rhodamine B was98.35% at 50 min under UV lamp,and its degradation efficiency was superior to pure titanium dioxide.?2?Nano-SnO₂ powders were prepared by homogeneous precipitation method using the SnCl₄·5H₂O as the source of tin,polyethylene glycol?PEG?as the surface coating agents andurea as the precipitant.The SnO₂/TiO₂ composite semiconductor photocatalyst was prepared by mixing SnO₂ with Ti?OH?4 prepared in the process by sol-gel method.The characterization results showed that SnO₂/TiO₂ with the molar ratio of SnO₂ and TiO₂ 1: 4,the calcination temperature 400? was mainly anatase TiO₂ and a small amount of rutile TiO₂.The particle size of SnO₂/TiO₂ was about 14.8nm,which had a stronger responsive to visible light.The photocatalytic results showed that the degradation rate of rhodamine B could reach 98.2% at35 min under UV lamp,and its degradation efficiency was better than SnO₂-TiO₂ composite semiconductor photocatalyst prepared by sol-gel method.In the sunlight,the degradation rate of rhodamine B was 90.6% at 105 min.?3?SnO₂/TiO₂ composite semiconductor photocatalyst with better activity was optimized,then by doped to prepare SnO₂/TiO₂/GO composites by ultrasonic compounding method,with graphene oxide of 0.5%,1%,2% and 5%,respectively.The results showed that G5 photocatalyst obtain the good crystal structure and the response to visible light was the best.The photocatalytic results showed that the efficiency of rhodamine B was 99.2% at 35 min under UV lamp,and its degradation efficiency was better than that of SnO₂/TiO₂ composite semiconductor photocatalyst.The degradation rate reached 93.1% at 105 min in sunlight.?4?The reaction kinetics of degradation rate of rhodamine B of SnO₂-TiO₂,SnO₂/TiO₂ and SnO₂/TiO₂/GO photocatalysts were investigated under UV lamp.The results showed that the photocatalytic reaction was in accordance with the quasi-first order reaction kinetics...