Sonolysis induced decomposition of metal carbonyls: kinetics and product characterization.
The decomposition kinetics of Fe(CO)5 and Mo(CO)6 induced by sonolysis in hexadecane solvent was studied as a function of temperature (303-343 K) under an inert atmosphere. The decomposition data, obtained over at least two half lives in most of the runs, yielded first-order rate constant (k) values with correlation co-efficient (R2) > 0.95. The products were characterized by various spectroscopic techniques. The transmission electron microscopy (TEM) yielded images from which the mean particle diameter (MPD) of approximately 10 nm for Fe and < 3 nm for Mo were estimated. The generation of amorphous Fe and semi-crystalline Mo particles was determined from line broadening and corresponding d-spacing values in the X-ray diffraction (XRD) spectra. The XAFS/XANES data were consistent with the production of Fe(0) metal but carbided Mo (Mo2C). The one-step production of high-yield pyrophoric products demonstrated the applicability of sonolysis to effectively produce gram-quantity of zero-valent metals.
Department of Energy Sciences and Technology, Brookhaven National Laboratory, Upton, NY 11973-5000, USA. dmahajan@bnl.gov
Devinder
D
Mahajan
Elizabeth T
ET
Papish
Kaumudi
K
Pandya