Microwave-assisted Synthesis And Photocatalytic Activtiy Of C/N-codopted TiO₂Microspheres For The Degradation Of Acid Red G Under Visible-light Irradiation

The band gap of TiO2is3.2eV, traditional TiO2materials can’t use solar energyfully. How to get TiO2photocatalyst which has high visible light activity has been ahot topic. Many methods can be used to modify TiO2to enhance visible lightadsorption. But traditional preparation processes are complex and time-consuming.Therefore, it’s necessary to study the simple preparation method of TiO2photocatalyst with high visible light activity.Microwave is high-frequency electromagnetic wave, and is widely used in thepreparation of semiconductor materials. Microwave can increase the rate and productof a chemical reaction and even change the reaction.In this paper, C/N co-doped TiO2microspheres which has high visible light activitywas synthesized by microwave technology. A variety of characterization techniquessuch as XRD, SEM, TEM, XPS, N2adsorption/desorption, UV-Vis DRS, FTIR wereused to analysis the material. The results show that the material is pure anatasespherical particles and the diameters of the particles are all about20um. The surfacesare coated with a carbon layer which can absorb visible light, C and N weresuccessfully doped into the titania lattice which caused the lattice distortion andreduced the band gap to3.02eV. The absorption intensity of the material risesbetween400nm to500nm which proves the material can response to visible light.The material can degrade98%ARG (10mg/L) under visible light irradiation in3hwhich is three times as high as which of P25. The optimum conditions were filteredby experiments: ethanol250mL, tetrabutyl titanate10mL, NH4F0.26g, time ofreaction is5min and power of microwave is800W. The spherical structure graduallyformed with the addition of ethanol and NH4F, significantly improved photocatalyticeffect, but the spherical structure breaks up with too much of NH4F. The TiO2microspheres described has excellent visible effects and was rapidly prepared in5min.And the reaction conditions were mild, the material costs can be greatly reduced inthe future applications, so this material has practical significance.