MOCVD of iron with [(arene)(diene)Fe(0)] precursors in a fluidized bed reactor

MOCVD of thin iron films at moderate temperature (T < 200 °C) was investigated using two metal organic complexes of the type [(arene)(diene)Fe(0)] as precursor. [(1,3-Butadiene)(toluene)Fe(0)] (1) and [(1,3-cyclohexadiene)(toluene)Fe(0)] (2) were synthesized by metal vapor synthesis. They were characterized by their vapor pressure at different temperatures and their decomposition behavior. 1 and 2 were used to coat alumina powder with iron through MOCVD in a fluidized bed reactor (FB-MOCVD) to prepare potential supported iron metal catalysts. The new materials were compared to an iron coated sample, which was prepared by conventional wet impregnation technique. Both were characterized by different methods like ICP OES, SEM/EDX, particle size analysis, H2/TPR and CO adsorption. The iron layer of the FB-MOCVD samples forms nanocrystals, which are homogeneously distributed over the surface. They are much smaller in size and show a higher dispersion with respect to the conventionally prepared iron catalysts. As a consequence, the nanocrystals are significantly more reactive with respect to redox processes and adsorb about 40% more carbon monoxide, than the conventionally prepared material, thus indicating a higher catalytic activity.

Iron is widely used as catalyst for industrial applications. Compared to other conventional techniques (wet impregnation) metal organic chemical vapor deposition in fluidized bed reactors (FB-MOCVD) have advantage of production of high dispersed metal-supported catalyst. The homogeneity of the dispersion of iron particles over alumina using new [(arene)(diene)Fe(0)] complexes as precursor was shown. These complexes may overcome the disadvantages of the commercially available compounds. Figure optionsDownload as PowerPoint slide