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¡ï ¡ï tangjy(½ð±Ò+2):¸ÐлÌṩ£¡ 2010-11-18 08:54:49 zaizaim(½ð±Ò+10): 2010-11-18 08:57:12
ÎÒ×ö¹ýÌúµÄEPR£¬Ö÷ÒªÊÇg=2.0,2.2,4.3Èý¸ö·å£¬The co-ordination environment of Fe was further analyzed by EPR spectroscopy. The EPR spectrum of Fe-MCM-41 is shown in Figure 7. It appears that two signals, at g = 2.0 and 4.3, were mainly detected. The signal at g = 4.3 could be attributed to Fe(III) ion in tetrahedral co-ordination with strong rhombic distortion. The g value calculated at 2.0 is considered as octahedral, while such species are described as framework tetrahedral species. The absence of a weak signal at 2.2 in sample can be attributed to the absence of nonframework (superparamagnetic) iron oxide nanoparticles dispersed in the mesoprous channels. Thus, it is inferred that the iron species are exclusively in tetrahedral coordination in this material.£¨×Ô¼ºÎÄÕÂÀïµÂÒ»¶Î»°£¬ÈôÓдíÎóÇëÅúÆÀÖ¸Õý£©
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