以尿素为氮源制备氮改性二氧化钛及其改性机理

以钛酸丁酯为前驱体,以尿素为氮源,采用改进溶胶-凝胶法制备了不同N含量的改性TiO2光催化剂(N-TiO2).以重铬酸钾为目标污染物,以甲酸为空穴捕获剂,评价了可见光下该催化剂的催化还原活性.结果表明,N-TiO2催化剂活性明显高于未改性催化剂,当催化剂中N/Ti摩尔比为10%、焙烧温度为400℃时,其光催化还原活性最...

Preparation of Nitrogen-Modified Titania with Urea as Nitrogen Sourceand Its Modification Mechanism

A nitrogen-modified TiO2 (N-TiO2) catalyst with different nitrogen content was prepared by a modified sol-gel method, using tetrabutyl titanate as the precursor and urea as the nitrogen source. The catalyst samples were used in the photocatalytic reduction of Cr(Ⅵ) under visible light, using formic acid as a hole scavenger to enhance the photocatalytic reduction reaction. The results demonstrated that the N-TiO2 catalyst had higher photocatalytic activity than bare TiO2, and the N-TiO2 sample with 10% (molar ratio) nitrogen calcined at 400 oC held the highest photocatalytic efficiency. The N-TiO2 samples were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and ultraviolet visible diffuse reflectance spectroscopy. The results showed that the higher photocatalytic activity of the N-TiO2 sample calcined at 400 oC was mostly attributed to the melon condensation products, which acted as visible-light sensitizers.