三维有序大孔杂化材料SiW_(11)O_(39)^(8-)-SiO_2和γ-SiW_(10)O_(36)^(8-)-SiO_2的制备与表征

Preparation and Characterization of Three-dimensional Ordered Macroporous Hybrid SiW_(11)O_(39)^(8-)-SiO_2 and γ-SiW_(10)O_(36)^(8-)-SiO_2 Composites

通过溶胶 -凝胶和聚苯乙烯模板等方法制备了含缺位 Keggin阴离子 Si W1 1 O8- 3 9和 γ-Si W1 0 O8- 3 6的三维有序大孔杂化氧化硅复合材料 ,并通过紫外漫反射光谱 ( UV/ DRS)、傅里叶变换红外光谱 ( FTIR)、固体核磁共振波谱 ( MAS NMR)等手段对其结构进行了表征 .结果表明 ,杂化材料中的 Keggin阴离子仍保留其基本骨架结构 ,但其与氧化硅基体之间存在化学作用 .杂化材料的孔道结构用扫描和透射电子显微镜 ( SEM和TEM)进行表征 ,其平均孔径为 ( 335± 5 0 ) nm.对杂化材料孔壁的微孔性通过氮气吸附进行了测定 .此类材料对水溶液中羟基丁二酸的降解反应具有活性 ,光催化过程中未发现 Keggin阴离子自载体中脱落的现象 .

Three-dimensional ordered macroporous hybrid silica materials based on lacunary Keggin anions such as SiW 11O 8- 39 and γ-SiW 10O 8- 36 were prepared via sol-gel method as well as polystyrene templating technique. The structures of as-synthesized composites were characterized by UV diffuse reflectance spectra, FTIR, and solid-state MAS NMR. The results indicate that the primary Keggin structures remain intact in the hybrid materials, and chemical interaction exists between POM molecules and silica matrix. The porous structures of the composites were characterized by SEM and TEM, and their average pore diameters were (335±50) nm. The microporosity of the wall structure was evaluated by the nitrogen adsorption determination. The composites exhibit a photocatalytic activity to degrade aqueous malic acid under irradiation in the near-UV areas, and the leakages of the POMs from the hybrid materials are hardly observed during the process of photocatalysis.