Preparation, characterization and application of sulfonated mesoporous hollow carbon microspheres

摘要

Mesoporous hollow carbon microspheres (MHCM) with high specific surface area was prepared by using a core-shell structured mesoporous material of SiO2@SBA-15 as hard template, sucrose as carbon precursor via inverse replica method. Then, MHCM was sulfonated by diazonium coupling to synthesize sulfonated mesoporous hollow carbon microspheres (MHCM-DS). TEM images showed that hollow carbon microspheres were successfully formed. The small angle XRD patterns of SiO2@SBA-15 and MHCM confirmed these two materials were ordered mesoporous material. BET surface area and pore diameter distribution results indicated that MHCM had an area of 620m(2)/g and a double mesoporous with 2.7nm and 3.4nm pore diameter, respectively. After the MHCM being sulfonated, the area was reduced to 446m(2)/g. In addition, pore diameter distributions of 2.7nm and 3.4nm were weakened, and new pore diameter distributions in the range of 5-10nm were appeared meanwhile. Surface acid amount of sulfonated carbon microspheres (2.8mmol H+/g) was higher than unsulfonation carbon microspheres (2.2mmol H+/g). Besides, the FTIR result also demonstrated the existing of -SO3H. The catalytic activity of MHCM-DS was observed for transesterification and epoxidation reaction, respectively. For transesterification reaction, the highest yield of fatty acid methyl esters was 93wt% at 180 degrees C in 6h with 0.6g catalyst amount. For epoxidation reaction, when reaction temperature was 40 degrees C and reaction time was 6h, conversion and yield could both reach up to 50%.