Axil-- Your article regarding LiAlH4 catalyzed by Fe2O3 and Co2O3 noted the following:
>>>>>The onset temperature of LiAlH4 doped with 7 mol % Fe2O3 and Co2O3 have reduced by as much as 97 and 93 °C, respectively, compared with the pristine LiAlH4.<<<<< The article also identifies the release of H from the LiAlH4 material occurs at 400 to 500 C. I doubt that much hydride exists at 1400 C, but is a gas in the inner reactor cylinder described in the Rossi patent application even without the addition of the Fe2O3 or Co2O3 as a catalyst for desorbtion. What is need is data on the dehydrogenation properties of LiAlH4 as a function of temperature and the diffusion rate of H through the alumina. I would think that something that reduces desorption or diffusion of H is a more desirable additive to control H availability for the LENR process in the hotter zone of the reactor. Bob Cook ----- Original Message ----- From: Axil Axil To: vortex-l Sent: Tuesday, November 11, 2014 9:34 AM Subject: [Vo]:About iron and cobalt in Rossi's fuel http://www.eng.usf.edu/~volinsky/LiAlH4CatalyzedByNanoparticles.pdf Dehydrogenation Improvement of LiAlH4 Catalyzed by Fe2O3 and Co2O3 Nanoparticles This bit of info might be of interest to those who are replicating Rossi's reactor. I just ran across this paper on hydrogen storage. Adding a bit of iron oxide to lithium aluminum hydride reduces the desorption temperature of the hydride. This might explain why iron and cobalt was found in the Rossi fuel charge. CONCLUSIONS In summary, the dehydrogenation properties of LiAlH4 doped with Fe2O3 and nanoparticles exhibit a dramatic improvement compared with that of as-received LiAlH4. The nonisothermal hydrogen desorption analysis reveals that the addition of increasing amounts of Fe2O3 and Co2O3 nanoparticles to LiAlH4 results in a progressive reduction of the onset temperature of LiAlH4. The onset temperature of LiAlH4 doped with 7 mol % Fe2O3 and Co2O3 have reduced by as much as 97 and 93 °C, respectively, compared with the pristine LiAlH4. Between various Fe2O3- and Co2O3-doped samples, the 5 mol % oxide-doped samples are found to be the optimal materials with the highest released hydrogen capacity and substantially reduced activation energy for the LiAlH4 dehydrogenation. Isothermal volumetric measurements reveal that LiAlH4 + 5 mol % Fe2O3 and LiAlH4 + 5 mol % Co2O3 samples can release about 7.1 and 6.9 wt % hydrogen in 70 min at 120 °C, whereas the as-received LiAlH4 only releases about 0.3 wt % hydrogen for the same temperature and time. The DSC and Kissinger desorption surface catalyst and are reduced to Co3O4 during the ball-milling process, and then translate to CoO when heated to 250 °C. Therefore, it is reasonable to conclude that the finely dispersed Fe oxide, Li−Fe oxide, and Co oxide may contribute to dehydrogenation kinetics improvement and provide a synergetic catalytic effect by serving as active sites for nucleation and growth of the dehydrogenated products, resulting in the shortening of the diffusion distance of the reaction ions. Meanwhile, the reduction of high valence transition metals during heating may play an important role in improving the kinetic desorption of the doped samples. In summary, it is reasonable to conclude that Fe2O3 and Co2O3 nanoparticles are promising additives for remarkably improving the dehydrogenation performance of LiAlH4, and the Fe2O3kinetics analyses reveal that the apparent activation energies of as-received LiAlH4 are 94.8 and 172.3 kJ/mol, while the Ea of the 5 mol % Fe2O3-doped sample declines to 54.2 and 86.4 kJ/mol, resulting in declined rates of 42.8 and 50.0%, respectively, for the first two decomposition reactions. Furthermore, FTIR, XRD, and XPS demonstrate that LiAlH4 reacts with Fe2O3 during ballmilling by local forming of Fe oxide species with a lower oxidation state and a mixed Li−Fe oxide. These finely dispersed dehydrogenated products would contribute to the dehydrogenation kinetics improvement and provide a synergetic catalytic effect for the remarkably improved dehydrogenation kinetics of nanoadditive is more efficient than the Co2O3 nanoadditive.
