氮掺杂TiO2光催化剂的制备及可见光催化性能研究

在溶胶-凝胶法基础之上，以尿素为氮源，通过较温和的反应条件来制备氮掺杂TiO₂光催化剂。以亚甲基蓝为模型化合物、日光色镝灯为光源，探索了其可见光光催化性能；并用XRD、低温氮气吸附-脱附技术、UV-Vis等表征了其结构特征；同时以对苯二甲酸为探针分子，结合化学荧光技术研究了光催化体系中·OH自由基的变化规律，进一步验证了其光催化活性规律。结果表明：氮掺杂能引起TiO₂光催化剂的激发吸收光谱明显红移并具较好的可见光响应性；在不同煅烧温度和尿素/钛酸丁酯物质的量的比

Preparation and Visible-light Responsive Photocatalytic Activity of N-doped TiO2 Photocatalyst

The N-doped TiO₂ photocatalyst was prepared based on the sol-gel method in a mild condition with urea as the nitrogen source. The photocatalytic activity to visible-light of the N-doped photocatalyst was investigated using methylene blue as the photodegrading compound, and Dy-lamp as the visible-light source. The structure properties of the photocatalyst were characterized via XRD, low-temperature nitrogen adsorption-desorption techniques and UV-Vis diffuse reflectance spectroscopy. The hydroxyl radical ·OH produced in the photocatalytic system was studied via a fluorescence spectroscopy, and terephthalic acid was used as the hydroxyl radical capturer. The results indicate that the N-doping could make the light absorption of the photocatalyst obviously extended into visible-light region, and increase the visible-light responsive photocatalytic activity. The photocatalytic activity of the obtained photocatalyst was gently weakened with the increasing of calcination temperature, and gently increased with the increasing of molar ratio of urea to Ti[O(CH₂)₃CH₃]₄. The variation in fluorescence intensity was consistent with the photocatalytic activity, i.e. the greater the amount of OH, the higher the photocatalytic activity of the N-doped TiO₂ photocatalyst.