高热稳定性有序介孔TiO_2/活性炭制备及其孔-孔协同光催化性能

以十六烷基三甲基溴化铵(CTAB)表面活性剂和钛酸四丁酯分别为造孔模板和钛源,通过超声辅助溶剂挥发自组装技术制备有序介孔氧化钛(ordered mesoporous Ti O2,OMPT)及其活性炭负载体(ordered mesoporous Ti O2/AC,OMPTA).为探讨OMPTA结构与性能之间的关系,采用超声辅助溶胶-凝胶技术合成了无孔氧化钛/活性炭(nonporous Ti O2/AC,NPTA)负载体,利用热重-差热(TG-DTA)、X射线衍射(XRD)、氮气吸附-解吸、透射电子显微镜(TEM)和紫外漫反射(DRS)等手段对制备材料结构进行表征.以酸性红B(acid red B,ARB)的光催化降解为探针实验,评价OMPTA的光催化性能和使用寿命,提出了孔-孔协同光催化扩增机制,并探讨了催化条件(染料浓度、催化剂浓度和溶液p H)对协同扩增效果的影响.结果表明:相对于纯OMPT,OMPTA具有晶粒生长的高活化能、较小的粒径尺寸和对有序介孔结构的高热稳定性,这归功于活性炭的吸附力和非晶相层对晶粒生长的阻碍作用.由于孔-孔协同光催化扩增效应,导致OMPTA在NPTA、OMPT-AC、OMPT、P25和NPT中具有更高的催化活性.热处理温度强烈影响OMPTA的光催化活性,其中OMPTA-500具有最高的光催化活性,这归功于其具备完善的结晶性、相对高浓度的羟基和Ti3+离子.同时,OMPTA-500在重复使用过程中也具有很高的光催化性能.当使用OMPTA-500为催化剂对ARB降解时,最佳的催化条件为催化剂浓度1 g/L,ARB浓度15 mg/L,p H 5.

Preparation of ordered mesoporous Ti O_2/activated carbon with high thermal stability and hole-hole synergistic photocatalytic property

By surfactant template technique with the aid of ultrasound systerm, the ordered mesoporous titania（OMPT） and OMPT/activated carbon（OMPTA） were prepared using cetyl trimethyl ammonium bromide（CTAB） surfactant and tetrabutyl titanate as creating-pore template and titanium source, respectively. To explore the relationship between structure and properties OMPTA, ultrasound-sol-gel technique was applied to synthesize nonporous titania dioxide/activated carbon（noporous Ti O2/AC, NPTA）. The obtained material structure was characterized by thermogravimetric-differential thermal（TG-DTA）, X-ray diffraction（XRD）, nitrogen adsorptiondesorption, transmission electron microscopy（TEM） and UV diffuse reflectance（DRS）. OMPTA photocatalytic performance and service life were evaluated by means of acid red B（ARB） as a probe photocatalytic degradation experiments. The hole-hole synergistic amplification mechanism of photocatalytsis was proposed and the effects of catalytic conditions（dye concentration and catalyst concentration） on synergistic amplification were explored. The results show that： compared to pure OMPT, OMPTA has grain growth with high activation energy, the smaller particle size and mesoporous structure for high thermal stability, because the activated carbon adsorption and amorphous phases hinder the crystalline grain growth. Due to hore-hole synergistic amplification effect of photocatalytsis, OMPTA has the highest catalytic activity among NPTA, OMPT, P25, OMPT-AC mixture and NPT. The heat treatment temperature is strongly affected OMPTA photocatalytic activity, and OMPT-500 has the highest photocatalytic activity. It is attributed to the fact that it has perfect crystallinity, a relatively high concentration of hydroxyl and Ti3＋ ions. Meanwhile, OMPTA-500 also shows high photocatalytic properties in the repeated usage. When ARB is degraded by OMPTA-500, the optimum catalytic conditions are catalyst concentration of 1 g/L with ARB concentration of 15 mg/L and p H 5.