The Preparation Of Two Series Of Iron Oxide Aerogel And The Research On The In-Situ Formation Of MPc/Iron Oxide Nano-composite

This work consists two major parts:one is the preparation of nano-metal oxide,the other concerns about the in-situ formation of MPc/Metal oxide nano composite. The preparation of nano metal oxide Nowdays major methods used to prepare α-Fe₂O₃,usually need to be sintered between 400⁵00℃to achieve the transformation of α-Fe₂O₃.However ,under such high temperature ,conglameration will occur between nanoparticle inevitably.We used iron nitrate (Fe(NO₃)₃ ) and iron ethoxide (Fe(OC₂H₅)₃) respectively as precursor of gel.These two kinds of gel then were treated with supercritical ethanol,after that, two kinds of aerogel were obtained. As a result, the iron ethoxide-derived gel was transferred to α-Fe₂O₃ completely under the treatment of SC ethanol,need no further calcination.The analysis of size and size distribution shows that the mean size of the powder is about 55.2nm,the size distribution is very nrrow,mostly range between 40⁵0nm,the powder shows highly selective sensitivity toward ethanol. On the other hand,however,the iron nitrate-derived aerogel consists γ-Fe₂O₃ and a large part of amorphic iron oxide.We also studied the transformation of the aerogel under the treatment of various temperatures. Studies about the in-situ formation of the MPc/metal oxide composite The major methods of fabricating MPc/metal oxide include the method of mechanical mixing,dipping,and chemical modification.The former two methods is relative simple,however,the MPc is merely physically attached to the surface of metal oxide, which could lead to easily leaching of MPc.Using the third method,Mpc can be chemically bonded to the metal oxide via the chemical modification of silane,through that way,although the MPc can be immobilized,the process is cumbersome. A new method of fabricating MPc/Metal oxide nano composites was reported in this paper. The active Fe³⁺ on the surface of SCFD-derived Fe₂O₃ aerogel and phthalonitrile act as template and components respectively during the process of the self-assembly of FePc. As compared to the sample derived from dipping method, the chemically bonded interaction between FePc and Fe2O3 nanoparticle in the resulting material was observed. Interestingly,Of the two kinds of aerogel mentioned above,only the iron nitrate-derived aerogel could react with phthalonitrile results in FePc.