Preparation Of Visible Light Driven Modified TiO₂Photocatalysts And Their Properties For Organic Pollutants Degradation

China is known as a resource-induced water shortage country for it meets less than a quarter of the world’s average per capita water capacity. At the same time, it is regarded as a water quality-induced water shortage country because the water quality can not achieve the state standards of drinking water quality. The water pollution issue in China is quite serious, especially in many developed industrial towns near by rivers. Water pollution has posed a threat to the industrial and agricultural production, as well as the health of the people in our country.Being less secondary pollutions, effective to mineralize organic pollutants and simple to handle, semiconductor photocatalytic oxidation technology has a potential development prospects in environment remediation. Among numerous photocatalysts, TiO2is knowed as one of the most prospects due to its chemical stability, non-toxic and the low price. However, it can only be activated under UV light, which limits its visible light utilization. Therefore, to design and synthesize a visible light activated modified TiO2is still a challenging work up to now.In this work, firstly, Bi2O3/TiO2-xBx photocatalyst was synthesized by sol-gel method. The resulting samples were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, high resolution transmission electron microscopy, nitrogen adsorption, and UV-Vis diffuse reflectance spectroscopy. The O2-in the lattice of TiO2was replaced by B3+, resulting the forbidden band of TiO2narrowed, thus it could be activated under visible light irradiation. The results of degradation experiment over PCP confirmed the Bi2O3on TiO2-xBx could promote the photocatalytic activity significantly. We deduced that the combined Bi2O3could decrease the recombination of electron-hole pairs. In addition, we proposed the degradation mechanism of PCP on the basis of liquid chromatography mass spectrometry analysis.Secondly, we prepared N, Si-codoped TiO2by an ultrasonic spray pyrolysis method. The as-prepared catalysts were systematically characterized and their photocatalytic activities were evaluated for degradation of SA. We found that Ti4+were replaced by Si4+, and N3-incorporated into the interstitial site of TiO2, thus expanded its absorbance to visible light. Analylizing of degradation products of SA by gas chromatography mass spectrometry, several reduction products of SA were detected. The possible degradation mechanism related to the reduction effect of electrons was proposed.