高比表面积蠕虫状介孔SnO_2的合成与表征

Synthesis and Characterization of Wormhole-Like Mesoporous SnO_2 with High Surface Area

以聚乙二醇(PEG)为模板剂,氯化锡为锡源,尿素为沉淀剂,采用水热法合成出高比表面积的蠕虫状介孔四方相金红石型SnO2.考察了PEG分子量及其浓度、水热温度和焙烧温度对SnO2孔结构和形貌的影响.采用X射线衍射、N2吸附-脱附、透射电镜、红外光谱和紫外-可见光谱等技术对样品进行了表征.结果表明,模板剂可被水洗除去,PEG分子量对介孔SnO2的比表面积影响不大,而PEG浓度、水热温度和焙烧温度的影响较大.在以分子量为6000的PEG与Sn的摩尔比为0.01的条件下,于120oC水热处理29h后可合成出比表面积高达161m2/g和平均孔径为2.6nm的蠕虫状介孔SnO2.所制得样品具有较好的紫外光吸收性能,适宜用作催化剂、载体和气体传感器等.

High-surface-area wormhole-like mesoporous SnO2 with a tetragonal rutile-type structure was fabricated adopting the hydrothermal strategy using poly（ethylene glycol） （PEG） as the template, tin chloride as the tin source, and urea as the precipitating agent. The effects of PEG with different molecular weights and its concentration, hydrothermal temperature, and calcination temperature on the pore structure and morphology of SnO2 were examined. The physical properties of these materials were characterized by X-ray diffraction, nitrogen adsorption-desorption, transmission electron microscopy, selected-area electron diffraction, infrared spectroscopy, and ultraviolet-visible diffuse reflection spectroscopy. It is shown that the PEG template could be removed by washing, no significant impact of PEG molecular weight was observed on the surface area of the mesoporous SnO2 samples, but the factors such as PEG concentration, hydrothermal temperature, and calcination temperature exerted considerable influence on the pore structure of the SnO2 samples. After the hydrothermal treatment at 120 oC for 29 h with the molar ratio of PEG （with a molecular weight of 6 000 g/mol） to Sn of 0.01, a wormhole-like mesoporous SnO2 sample with a high surface area of 161 m2/g and an average pore size of 2.6 nm was generated. The SnO2 samples exhibited good behavior in UV-light absorption. These porous materials are suitable for use as catalysts, supports, and gas sensors.