| TiO2, which is nontoxic, inexpensive, stable structure and excellent photocatalyticproperties, is one of the recently researches on the semiconductor photocatalyst. It canbe only in response to ultraviolet light with wide forbidden band (3.2eV). While thecorresponding to the energy of ultraviolet light, which wave length is less than380nm,accounts for3.39%to the energy of the total energy on the entire solar spectrumwavelength range. Therefore the energy utilization of TiO2as a photocatalyst is low. Inadditional, the photo-generated electron and photo-generated hole of TiO2are easy torecombine and the efficient of photocatalysis needs to improve. As a novel non-metallicsemiconductor material, g-C3N4has an advantage on light visible response with wideforbidden band about2.7eV, chemical stability and thermal stability. By delocalizedconjugated π bond, TiO2can be also used for organic contamination degradation, visibledecomposition of water into hydrogen and so on.To improve the photocatalysisefficient of TiO2, this paper launched a series ofinexpensive and easy available industrial melamine and metatitanic acid as rawmaterials, prepared g-C3N4/TiO2composite photocatalytic materials. The crystallinephases, structure, morphology, chemical form and optical performance of the sampleswere characterized by X-ray diffraction (XRD), Fouriertransform infrared spectroscopy(FT-IR), Transmission electron microscopy (TEM), Thermogravimetric-differentialscanning calorimetry analysis (TG-DSC), the N2gas adsorptionBrunauer-Emmett-Teller method (N2-BET), X-Ray photoelectron spectroscopy(XPS),Ultraviolet–visible diffuse reflection spectroscopy (UV-vis) and Three-dimensionalfluorescence spectroscopy (FS). And surveyed the calcination temperature, ratio of rawmaterials and roasting time on the material structure and properties of samples. Thenevaluate the preparation conditions on the properties of photocatalytic materials bychoosing methylene blue solution as target pollutant.The main research results of this paper are as follows.①With melamine and industrial metatitanic acid as raw materials, this paperprepared the g-C3N4/TiO2composite catalytic materials. The result of photocatalysisshows that the catalytic effective of composite catalytic materialincreasesremarkable. Italso figures that the ratio of raw material, calcination temperature and time exist the bestvalue. The catalysis experiment shows that the g-C3N4hybridized TiO2composites, which the proportion of melamine and metatitanic acid is1.0and calcined at500°C for1.5h, exhibited higher activity under visible light irradiation, while the photodegradationrate of10mg/L methylene blue reached to83%.②Therepresentation results show that g-C3N4/TiO2composite is formed by theanatase phase TiO2and the melamine pyrolysis condensation of carbon nitride layerstructure. It also points out that the wide forbidden band of samples is obviouslydecrease and the maximum absorption wavelength redshift. The specific surface areaand pore volume of samples are remarkable increase.③This study can provide a new treatment method for difficult degradation oforganic pollutants, and provide certain reference for practical environment functionmaterial. |
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