Preparation And Physicochemical Properties Of TiO₂ & TiO₂/Cu₂O Composite Photocatalyst

TiO₂ photocatalyst has the advantages of high photocatalytic activity,good thermal stability,relatively low price and no secondary pollution,and is considered to be one of the most ideal photocatalysts.Cu₂O photocatalyst is a typical metal-deficient p-type semiconductor material,and it is also a promising photocatalyst.The composite of TiO₂and Cu₂O photocatalyst can effectively reduce the recombination rate of photogenerated electron-hole.TiO₂/Cu₂O composite catalyst has better photocatalytic performance than single TiO₂ and Cu₂O.In this paper,the preparation of TiO₂ photocatalyst,Cu₂O photocatalyst and TiO₂/Cu₂O composite catalyst and its physicochemical properties were the main research contents.SEM,TEM,XRD,EDS,FT-IR,TG-DTA were used to characterize the physical properties of the samples.The photocatalytic reaction of Rhodamine B solution and methyl orange solution was used as a probe reaction.The preparation conditions and photocatalytic reaction conditions of TiO₂ photocatalyst,Cu₂O photocatalyst and TiO₂/Cu₂O composite catalyst were systematically studied.The TiO₂ photocatalyst with regular morphology,uniform dispersion and high photocatalytic activity can be successfully prepared by the optimized sol-gel method.The prepared TiO₂ photocatalyst is a mixed crystal phase of anatase and rutile with anatase phase.Mainly,its crystallinity is high,and its morphology is spherical particles with a particle size of about 150 nm.The preferred preparation conditions and reaction conditions of the TiO₂ photocatalyst are as follows:ethanol as solvent,volume ratio of titanium to water is 10:1,volume ratio of titanium alkoxide is 8:1,calcination temperature is 650?,calcination time is 5 h,initial concentration of rhodamine B solution is 4 mg/L,and the amount of TiO₂ photocatalyst was 0.04 g.Under UV irradiation,the degradation rate of rhodamine B solution reached a maximum of 95.9%when exposed to light for 4 h.The Cu₂O photocatalyst with regular morphology and uniform particle size can be successfully prepared by simple chemical precipitation method.The morphology and catalytic activity of Cu₂O samples can be controlled by changing the reaction conditions.The prepared Cu₂O photocatalyst has high purity and high crystallinity.The Cu₂O particles have an octahedral configuration with an edge length of about 2?m and uniform dispersion.The preferred preparation conditions and reaction conditions are:the amount of polyvinylpyrrolidone?PVP?is 10.8 g,concentration of NaOH solution is 2 mol/L,reaction temperature is 55?,crystallization time is 4 h,methyl orange solution's initial concentration is 20 mg/L,the amount of Cu₂O is 0.1 g.When exposed to visible light for 4h,the degradation rate of methyl orange solution reached 75.6%.The TiO₂/Cu₂O composite catalyst with excellent physicochemical properties can be successfully prepared by liquid phase method.The morphology and catalytic properties of the product can be controlled by changing the reaction conditions.In the TiO₂/Cu₂O composite catalyst,spherical particles of TiO₂ are uniformly coated on the surface of Cu₂O crystal.Under visible light irradiation,when the molar ratio of Cu²⁺/Ti⁴⁺is 10:1,methyl orange solution's initial concentration is 20 mg/L,and the amount of TiO₂/Cu₂O photocatalyst is 0.1 g.When the light time is 4 h,the degradation rate of methyl orange solution can be the maximum value is 89.8%.Under the ultraviolet-visible combined light source,when the molar ratio of Cu²⁺/Ti⁴⁺is 1:1,methyl orange solution's initial concentration is 20 mg/L,and the amount of TiO₂/Cu₂O photocatalyst is 0.1 g.When the light time is 4 h,the degradation rate of methyl orange solution can be the maximum value is 94.4%.