Ag-TiO_2/KIT-6复合纳米光催化剂的研究  

Studies on Ag-TiO_2/KIT-6 Composite Nanosized Photocatalyst

作　　者：张凤利[1] 郑远辉[1] 詹瑛瑛[1] 林性贻[1] 张汉辉[2] 郑起[1] 

机构地区：[1]福州大学化肥催化剂国家工程研究中心,福建福州350002 [2]福州大学化学系,福建福州350002

出　　处：《光谱学与光谱分析》2009年第8期2166-2170,共5页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(20771025);福建省重大专项项目(2005H201-2)资助

摘　　要：以有序介孔SiO2(简称KIT-6)为载体,采用钛酸丁酯水解法将纳米TiO2与KIT-6复合,并通过沉积沉淀法将纳米Ag粒子负载于其上,首次制得Ag-TiO2/KIT-6复合光催化剂,并采用相同的方法制备了一系列相关的催化剂。以光催化降解甲基橙来评价其催化性能,光催化活性顺序为Ag-TiO2/KIT-6>Ag/TiO2>TiO2/KIT-6>TiO2>Ag/KIT-6。利用XRD、N2物理吸附、XPS、UV-Vis DRS和TEM对系列催化剂进行表征,结果表明Ag-TiO2之间形成的异质结和催化剂的大比表面积是Ag-TiO2/KIT-6具有最高光催化活性的重要原因。其中Ag-TiO2之间的异质结结构,有效抑制了光生电子和光生空穴在TiO2表面和体相内部的复合,提高了光催化活性;此外Ag-TiO2/KIT-6的大比表面积大大提高了催化剂的吸附能力,增加了催化剂与污染物的接触,达到快速光催化降解污染物的目的。In the present paper, ordered mesoporous silica （KIT-6） as support, nanosized TiO2 into KIT-6 was synthesized by titanium tetraisopropoxide hydrolysis. Then silver was loaded by deposition-precipitation method. Ag-TiO2/KIT-6 composite nanosized photocatalyst was firstly synthesized and a series of correlated catalysts were synthesized by the same preparation method. Methyl orange is presently adopted as a representative organic pollutant to evaluate the photocatalytic performance of the as-synthesized catalysts. The order of photocatalytic activity of the as-synthesized samples was found as Ag-TiO2/KIT-6〉 Ag/TiO2 〉TiO2/KIT-6〉TiO2 〉Ag/KIT-6. Detailed characterizations were conducted by techniques including XRD, N2 physi- cal adsorption, XPS, UV-Vis DRS and TEM. It was found that the Ag-TiO2/KIT-6 sample shows the highest photocatalytic activity, which should be attributed to the Ag-TiO2 heterojunction structure and higher BET surface area of the Ag-TiO2/KIT-6 sample. Ag-TiO2 heterojunction improves the separation of photogenerated electron-hole pairs, thus enhancing the photocatalytic activity; Ag-TiO2/KIT-6 sample possesses high BET surface area, which facilitates adsorption and transportation of dye molecules, also leading to higher photocatalytic activity.

关 键 词：XPS UV-VIS DRS异质结 Ag-TiO2/KIT-6催化剂 

分 类 号：O643.3[理学—物理化学]