Effects of Calcination Time on Structure and Activity of Porous TiO2-Al2O3 Photocatalyst

Photocatalytic oxidation has grown to be very impressive technique in dealing with environmental pollutions 1-3 .A number of published literatures have reported the satisfactory future both on fundamental theory and applicable research in this field.The development of new photocatalytic materials with high activity is always the research focus in this field.There are two ways to improve the photocatalytic activity of TiO 2 based materials.One is doping with other elements, such as noble metals 4,5 , heavy metals 6,7 and rare earth elements 8,9 .Another way is to prepare TiO 2 based composite photocatalytic materials, such as TiO 2 -SiO 2 10 and SnO 2 /TiO 2 11 .The preparation of TiO 2 -Al 2 O 3 composite was not reported in the previously published literatures.In our recent work, the combination of TiO 2 and HZSM-5 zeolite showed much improved photocatalytic activity on methyl orange degradation 12 .Here came the idea that combination of TiO 2 with SiO 2 and Al 2 O 3 might have satisfactory results since the HZSM-5 is composed of SiO 2 and Al 2 O 3 .The functions of SiO 2 to the influences on TiO 2 were discussed in other paper 13 .In this article, a novel porous TiO 2 -Al 2 O 3 composite nanomaterial was prepared by sol-gel preparation method.Precursors were composed of tetrabutyl titanate and aluminum isopropoxide.The composite materials were produced after calcination at 500 ºC for different time.The samples were characterized by XRD, SEM and specific surface areas and