AgBr/TiO_2异质结型复合可见光催化剂的制备及其光催化活性

以钛酸四丁酯、KBr、AgNO3为前体,合成了具有异质结结构的纳米AgBr/Ti O2复合可见光催化剂.利用XRD、TEM、HRTEM和UV-Vis等方法对催化剂的晶相组成、形貌、粒度、微观结构、吸光性能等进行了表征.光催化降解亚甲基蓝活性结果表明,复合与单组分催化剂的光催化活性顺序为:AgBr/Ti O2AgBrAg-Br/P25P25Ti O2.含光敏剂AgBr的复合及单组份催化剂由于具有对可见光的良好吸收性能而具有较高的光催化活性.对于AgBr/Ti O2光催化剂,随mAgNO3/mTi O2比的增加,光催化活性先增强后减弱,当mAgNO3/mTi O2=3.35时光催化活性最高,分析结果表明,该复合催化剂粒径约15 nm,分散均匀且形成了紧密接触的AgBr/Ti O2异质结微结构,在紫外可见区(250～800 nm)都具有最强的光吸收.

Preparation and Photocatalytic Activity of AgBr/TiO2 Heterojunction Complex Catalyst under Visible Light

Nanosized visible light complex photocatalyst of AgBr/TiO2 with heterojunction structure was synthesized using Ti（OC4H9）4,KBr and AgNO3 as precursors.The phase composition,particle morphology,size,microstructures and absorbance of these samples were characterized by XRD,TEM,HRTEM and UV-Vis spectra.The results of photocatalytic degradation to methylene blue showed that the activity order of these samples is of AgBr/TiO2 AgBr AgBr/P25 P25 TiO2.The complex and mono-component photocatalysts with photosensitizer AgBr have higher activity because of the strong absorption in visible light region.The photocatalytic activities of AgBr/TiO2 increase first and then decrease with increasing mass ratio of mAgNO3/mTiO2,in which the mass ratio of 3.35 has the highest photocatalytic activity.Analysis revealed that the particle size of this complex photocataylst is about 15 nm with homogeneous dispersion and has formed intimate contact heterojunction microstructure and has the strongest absorption in UV-Vis light region of 250～800 nm.