Br-N共掺杂TiO_2/磁性炭复合材料的制备及其可见光催化性能

Preparation and photocatalytic performance of Br-N codoped TiO_2/magnetic carbon composites

以活性炭(AC)为原材料,采用铁盐化学沉淀法耦合壳聚糖-戊二醛交联改性技术制备磁性活性炭(MAC)。以MAC为载体,采用溶胶-凝胶法制备不同Br/Ti掺杂比的Br-N共掺杂TiO_2/MAC可见光催化复合材料(Brx-N-TiO_2/MAC)。通过XRD、UV-Vis漫反射、BET吸附实验、SEM、XPS表征其结构和化学特征。以水杨酸为模型分子进行光催化降解,评价不同Brx-N-TiO_2/MAC材料的可见光催化活性。实验结果表明,相较于N-TiO_2/MAC可见光催化剂,Br-N共掺杂更能促进催化剂对可见光的吸收。Br_(0.35)-N-TiO_2/MAC对水杨酸的降解效果最好,暗吸附1h、光催化3h后,Br_(0.35)-N-TiO_2/MAC对水杨酸的降解率达到83%,高浓度水杨酸会对光催化反应产生一定的抑制作用,该催化材料重复利用三次后仍有78%的去除率,显示了较好的稳定性。

Magnetic activate carbon（MAC）coupled by chitosan-glutaraldehyde crosslinking technique was synthesized by ferric salts chemical precipitation method using activate carbon as raw meterial.Based on MAC,Br-N codoped TiO2/magnetic carbon composites（Brx-N-TiO2/MAC）were prepared by a facile sol-gel method.The synthesized composites were characterized by XRD,UV-Vis diffuse reflectance spectroscopy（DRS）,N2 adsorption-desorption test（BET）,SEM and XPS.The photocatalytic activity of the composites was evaluated by photocatalytic degradation of salicylic acid under visible light irradiation.Compared with N-TiO2/MAC,Brx-N-TiO2/MAC has a better photocatalytic performance.The degradation effect of Br0.35-N-TiO2/MAC to salicylic acid is the best,and the photocatalytic degradation rate of Br（0.35）-N-TiO2/MAC for 3hcan reach up to 83% after 1hdark absorption.High concentration of salicylic acid can inhibit the photocatalytic reaction rate of Brx-N-TiO2/MAC.After reused for three times,the removal rate of Br（0.35）-N-TiO2/MAC to salicylic acid can still reach 78%,which proves the composites have a good chemical stability.