Surfactant isomerization and dehydrogenation on FePt nanoparticles

Surfactant coated FePt nanoparticles were characterized using Fourier transform infrared spectroscopy (FTIR). The FTIR spectra indicate that there is a conversion of the alkyl chain of the surfactant from the oleyl form (cis-9-octadecenyl) to the elaidyl form (trans-9-octadecenyl) during the synthesis of the FePt nanoparticles. This is revealed by the presence of several vibrational absorption bands in the region of the olefinic CH stretching modes. The appearance of infrared absorption bands due to olefinic CH stretching is due to the presence of Fe in the nanoparticles. The FTIR spectrum of platinum nanoparticles does not reveal the presence of olefinic CH modes. The concentration of Fe in the FePt nanoparticles influences the intensity of the olefinic CH stretching modes. The high intensity of these olefinic CH modes in nanoparticles with high Fe concentration indicates that Fe acts as a catalyst for cis to trans conversion and may lead to dehydrogentation of the alkyl chains.