Rhodium(0) nanoparticles supported on nano oxide crystalline materials: preparation, characterization and catalytic use in hydrogen generation from the methanolysis of ammonia borane /

Download
2018
Özhava, Derya
Ammonia borane (AB) has been considered as a chemical hydrogen storage materials, because of its high hydrogen storage capacity (19.6 wt%), nontoxicity, and stability under ordinary conditions. Hydrogen stored in AB can be liberated by thermolysis or solvolysis. Hydrolysis and methanolysis are the two solvolysis reactions producing hydrogen gas from AB. Although the hydrolysis of AB has been investigated for years extensively, the methanolysis of AB has been considered as an alternative way of releasing hydrogen gas due to many advantages over hydrolysis. As for the hydrolysis, the hydrogen liberation from the methanolysis of AB also realized in the presence of a suitable catalyst. This dissertation covers the preparation and characterization of rhodium(0) nanoparticles supported on the surface of nanooxide materials (Rh(0)/nanooxides), namely hydroxyapatite, silica, alumina and ceria, as well as the examination of their catalytic activities in hydrogen generation from the methanolysis of AB. Firstly, Rh(0)/nanooxides were prepared in a simple and reproducible way by impregnating rhodium(III) or (II) ions on the surface of nanooxide followed by their reduction during the methanolysis of AB. They were then isolated from the reaction medium and characterized by using a combination of advance analytical techniques including ATR-IR, PXRD, TEM, HR-TEM, TEM – EDX, STEM-EDS, XPS, SEM, SEM-EDX, ICP-OES and N2 adsorption/desorption. Then, the kinetics of methanolysis of AB in the presence of Rh(0)/nanooxides were examined depending on catalyst concentration and temperature as well as catalytic lifetime, and heterogeneity tests were performed. Furthermore, the formation kinetics vi of rhodium(0) nanoparticles supported on nanosilica, nanoalumina or nanoceria during hydrogen generation from methanolysis of AB were investigated by using the hydrogen generation as reporter reaction.

Suggestions

Nanoalumina-supported rhodium(0) nanoparticles as catalyst in hydrogen generation from the methanolysis of ammonia borane
Ozhava, Derya; Özkar, Saim (2017-10-01)
Rhodium(0) nanoparticles were in situ formed from the reduction of rhodium(II) octanoate and supported on the surface of nanoalumina yielding Rh(0)/nanoAl(2)O(3) which is highly active catalyst in hydrogen generation from the methanolysis of ammonia borane at room temperature. The kinetics of nanoparticle formation can be followed just by monitoring the volume of hydrogen gas evolved from the methanolysis of ammonia borane. The evaluation of the kinetic data gives valuable insights to the slow, continuous n...
Palladium nanoparticles supported on cobalt(II,III) oxide nanocatalyst: High reusability and outstanding catalytic activity in hydrolytic dehydrogenation of ammonia borane
Akbayrak, Serdar; Özkar, Saim (2022-11-01)
A new palladium(0) nanocatalyst is developed to enhance the catalytic efficiency of precious metal catalysts in hydrogen generation from the hydrolytic dehydrogenation of ammonia borane. Magnetically separable Pd-0/Co3O4 nanocatalyst can readily be obtained by the reduction of palladium(II) cations impregnated on cobalt(II, III) oxide at room temperature. The obtained Pd-0/Co3O4 nanocatalyst with 0.25% wt. palladium loading has outstanding catalytic activity with a record turnover frequency of 3048 min(-1) ...
Ruthenium nanoparticles supported on nanotubes/nanowires: highly active and long lived nanocatalysts in hydrolytic dehydrogenation of ammonia borane /
Akbayrak, Serdar; Özkar, Saim; Department of Chemistry (2016)
Ammonia borane (NH3BH3, AB) is one of the most promising solid hydrogen storage materials due to its high hydrogen storage capacity (19.6% wt.), non-toxicity and high stability under ambient conditions. Ammonia borane can release hydrogen upon hydrolysis in the presence of suitable catalysts even at room temperature. Although a large variety of catalysts have been tested in hydrogen generation from the hydrolysis of ammonia borane, the development of efficient, long-lived, reusable catalysts is still an imp...
Rhodium(0) nanoparticles supported on nanosilica: Highly active and long lived catalyst in hydrogen generation from the methanolysis of ammonia borane
Ozhava, Derya; Özkar, Saim (Elsevier BV, 2016-02-01)
Nanosilica stabilized rhodium(0) nanoparticles (Rh(0)/nanoSiO(2)), in situ formed from the reduction of rhodium(II) octanoate impregnated on the surface of nanosilica, are active catalyst in hydrogen generation from the methanolysis of ammonia borane at room temperature. Monitoring the hydrogen evolution enables us to follow the kinetics of nanoparticles formation. The resulting sigmoidal kinetic curves are analyzed by using the 2-step mechanism of the slow, continuous nucleation and autocatalytic surface g...
Copper(0) Nanoparticles Supported on Silica-Coated Cobalt Ferrite Magnetic Particles: Cost Effective Catalyst in the Hydrolysis of Ammonia-Borane with an Exceptional Reusability Performance
KAYA, MURAT; Zahmakıran, Mehmet; Özkar, Saim; Volkan, Mürvet (2012-08-01)
Herein we report the development of a new and cost-effective nanocomposite catalyst for the hydrolysis of ammonia-borane (NH3BH3), which is considered to be one of the most promising solid hydrogen carriers because of its high gravimetric hydrogen storage capacity (19.6% wt) and low molecular weight. The new catalyst system consisting of copper nanoparticles supported on magnetic SiO2/CoFe2O4 particles was reproducibly prepared by wet-impregnation of Cu(II) ions on SiO2/CoFe2O4 followed by in situ reduction...
Citation Formats
D. Özhava, “Rhodium(0) nanoparticles supported on nano oxide crystalline materials: preparation, characterization and catalytic use in hydrogen generation from the methanolysis of ammonia borane /,” Ph.D. - Doctoral Program, Middle East Technical University, 2018.