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以钛酸丁酯为原料,乙酸为有机配体,甲酰胺为干燥控制化学添加剂(DCCA),采用溶胶-凝胶法和溶剂置换等后续工艺,实现了块状TiO2气凝胶催化剂的常压干燥法制备,并考察了有机配体对气凝胶结构性能的影响。采用XRD、BET、SEM、EDS及DSC-TG对样品进行表征。结果表明:当有机配体与钛酸丁酯物质的量之比为0.9时,制备的样品性能最佳,该TiO2气凝胶样品为非晶态,表观密度为0.25g.cm-3,比表面积716.5m2.g-1,平均孔径19.1nm;在850℃大气气氛下热处理2h后,比表面积为122.4m2.g-1,平均孔径23.4nm,具有较高光催化活性;经1000℃热处理后,TiO2晶型仍为锐钛矿相,热稳定性较好,光催化活性有所降低。未采用有机配体制备的TiO2气凝胶表观密度为0.57g.cm-3,比表面积为482.2m2.g-1。有机配体的使用更有利于制备出表观密度较小、比表面积较高的TiO2气凝胶。
Using butyl titanate as raw material, acetic acid as organic ligand and formamide as drying control chemical additive (DCCA), the atmospheric pressure of bulk TiO2 airgel catalyst was achieved by using sol-gel method and solvent replacement. Dry preparation, and investigated the effect of organic ligand on the structure and properties of airgel. The samples were characterized by XRD, BET, SEM, EDS and DSC-TG. The results show that when the ratio of organic ligand to butyl titanate is 0.9, the prepared sample has the best performance. The TiO2 airgel sample is amorphous with an apparent density of 0.25g.cm-3, The specific surface area is 716.5m2.g-1 and the average pore diameter is 19.1nm. After heat treatment at 850 ℃ for 2h, the specific surface area is 122.4m2.g-1 and the average pore diameter is 23.4nm, which has high photocatalytic activity. After heat treatment at 1000 ℃ , The anatase phase is still anatase phase, the thermal stability is good, the photocatalytic activity is reduced. The apparent density of TiO2 airgel prepared without organic ligand was 0.57g.cm-3 and the specific surface area was 482.2m2.g-1. The use of organic ligands is more conducive to the preparation of a smaller apparent density, higher specific surface area of TiO2 airgel.