Dimetilamin boranın dehidrojenlenmesinde katalizör olan seryum oksit destekli bakır(0) ve titanyum oksit destekli rodyum(0) nanoparçacıklar

In recent years, hydrogen is accepted as clean and important energy carrier in the most applications such as heating, electrical generation, transportation and mechanical power. The lack of safe, effective and cost-effective hydrogen storage sources for transportable and stationary applications is one of the main obstacles to overcome for the application of the hydrogen economy. Chemical storage materials consist of high percent of hydrogen by weight are hopeful as hydrogen sources using in fuel cells. The hydrogen sources such as ammonia borane and its derivatives have the high gravimetric storage density, high stability and non-toxicity, so interest in them is increasing day by day. One of them, dimethylamine borane (Me)2NH.BH3, DMAB) could release hydrogen by means of proper catalyst in mild conditions. Transition metal nanoparticles can be utilized as active catalysts for the dehydrogenation of amine borane adducts due to the unique properties of them. The tendency of metal nanoparticles to agglomerate with the formation of bulk metal causes a significant decrement of activity with increasing particle size in their catalytic applications. Metal oxides used as a support are one of the way to avoid from agglomeration of metal nanoparticles. The usage of metal oxides as a stabilizer in the synthesis of transition metal nanoparticles supply advantegous in terms of long lifetime, thermal stability, and reusability for catalysts. In this dissertation, we reveal the in-situ preparation, characterization and catalytic activity of ceria supported copper(0) and titania supported rhodium(0) nanoparticles in dehydrogenation of DMAB. Copper(0) nanoparticles supported on ceria were in situ generated from the reduction of Cu2+/CeO2 during the catalytic dehydrogenation of DMAB in toluene. Rodium(II) hexanoate was used as a precursor to be formed rhodium(0) nanoparticles, Rh(0)/nanoTiO2 throughout the dehydrogenation of DMAB at temperature of 60.0 ± 0.5 oC. The characterization of metal oxides supported transition metal(0) nanoparticles were performed by means of UV-Visible electronic absorption spectroscopy (UV-Vis), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Energy dispersive X-ray (EDX), Brunauer-Emmett-Teller (BET), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), inductively coupled plasma optical emission spectrometry (ICP-OES and FT-IR techniques. The catalytic activity of ceria supported copper(0) and titania supported rhodium(0) nanoparticles was performed in the dehydrogenation of DMAB. The catalytic activity of ceria supported copper(0) and titania supported rhodim(0) nanoparticles and kinetics of hydrogen generation from the dehydrogenation of DMAB were tested depending on catalyst concentration and temperature. The obtained kinetic data was used for the calculation of rate laws and activation parameters such as Arrhenius activation energy, Ea; activation enthalpy, ΔH#; and activation entropy, ΔS# for both catalytic dehydrogenation reactions.