Characterization of MnO_2 Aerogels Prepared via Supercritical Drying Technique

The MnO2 aerogels were prepared from KMnO4 and allomaleic acid via sol-gel process and supercritical drying technique.The porous morphology,structure and composition of the aerogels were characterized by SEM,TEM,XRD,XPS,BET surface area,IR and TG/DSC.The effects of dehydration temperature on the aerogels structure were investigated.The results indicate that the proper mole ratio of reactants is favorable to the syntheses of MnO2 gels with the average valence states of manganese being close to 4.The resulting aerogels are hydrophilic,non-crystalline and monolithic porous materials with continuous,interpenetrate and three-dimensional network structure,which consist of nanoscale MnO2 colloidal particles with mean particles size of 10nm and mean pore diameter of 100nm.The aerogels morphology maintain unchanged during the heat treatment of dehydration at conventional temperature.