摘要: 为了准确测定多孔材料的比表面积，利用 N2 吸附法对多个具有 0.5~40 nm 不同孔径的样品进行孔结构分析，通过多点 BET 法计算样品的比表面积。 结果表明：多点 BET 法的相对压力取值范围与样品的孔径密切相关；对于微孔样品，相对压力取值范围一般为 0.01~0.1；对于孔径小于 4 nm 的介孔分子筛，相对压力取值范围应为 0.05~0.2；对于孔径大于 4 nm 的介孔材料， 相对压力取值范围一般为 0.05~0.3；对于多级孔分子筛，应根据类型及孔结构特征确定相对压力取值范围。
关键词: 多孔材料；多点 BET 法；比表面积；相对压力；孔结构
Abstract: To measure the specific surface area of pore materials， N2adsorption method was applied to analyze the pore structure of samples with pore diameters from 0.5 to 40 nm. The specific surface areas of these samples were obtained by the multi-point BET method. The results show that the ranges of relative pressure are closely related to the pore diameter of samples by the multi-point BET method. The relative pressure is in the range of 0.01 to 0.1 for microporous materials. The relative pressure is in the range of 0.05 to 0.2 for mesoporous materials with the pore diameter less than 4 nm. The relative pressure is in the range of 0.05 to 0.3 for mesoporous materials with the pore diameter larger than 4 nm. For hierarchical molecular sieves， the relative pressure value range should be determined according to their types and pore structure characteristics.
Keywords : pore materials； multi-point BET method； specific surface area； relative pressure； pore structure
