用氮气吸附法研究二甲醚催化剂表面分形维数

Study on Surface Fractal Dimensions of Different Dimethyl Ether Catalysts by N_2 Adsorption Method

在77K下对四种二甲醚催化剂进行N2吸附—脱附等温线测定,得到了催化剂的孔结构参数,研究了其孔径分布、比表面积、等温线形态变化,并利用等温吸附数据计算其分形维数。结果表明,四种催化剂分形维数在2～3之间,将催化剂颗粒机械成型得到的片剂都具有分形特性,但其分形维数与比表面积和孔容积没有直接联系。

Nitrogen adsorption desorption isotherms of four kinds dimethyl ether catalysts are measured at 77 K and the pore structure parameters are obtained, the pore size distribution, specific surface area and the morphology of isotherms of the different catalysts are studied. The fractal dimensions are examined by adsorption data of the isotherms. The result shows that the four fraetal dimensions are in the range between 2 -3, the tablets made from catalytic granules by machine -moulding have fractal characteristics, but there is no direct relationship between the fractal dimensions and specific surface areas and pore volumes.