Local atomic structures of hematite nanoparticles studied with XAFS

摘要

Hematite nanoparticles which were coated,respectively,with sodium dodecyle benzene sulphonate(DBS) and cetyltrimethyl ammonium bromide(CTAB) were synthesized by using microemulsion method in the system of water/toluene.The particle size and shape were characterized with transmissuon electron microscopy(TEM).The TEM results show that the nanoparticles take the shape of shpere with dimeter of 5.0nm and 6.0nm for modified DBS and CTAB respectively.The local atomic structures of these nanoparticles were probed by using XAFS technique.Fe-K absorption spectra were collected at beam line 4W1B of BSRF.The local atomic structure in DBS coated hematite was found to be similar with that in bulk hematite except the anharmonicity increasing,but about 0.04 A expansion of Fe-O bond length in CTAB-coated hematite,The interface/surface atomic configuration were compared and discussed.