Magnetically Separable Rh-0/Co3O4 Nanocatalyst Provides over a Million Turnovers in Hydrogen Release from Ammonia Borane

2020-03-16
Akbayrak, Serdar
Tonbul, Yalcin
Özkar, Saim
Cobalt(II,III) oxide nanopowders are used as supporting materials for rhodium(0) nanoparticles forming Rh-0/Co3O4 nanocatalysts, which can be prepared by impregnation and sodium borohydride reduction of Rh3+ ions on the surface of the oxide support. Magnetically separable Rh-0/Co3O4 nanoparticles are isolated from the reaction medium by an external magnet and characterized using various analytical techniques. Rh-0/Co3O4 nanoparticles are highly active and reusable catalysts with a long lifetime in hydrolytic dehydrogenation of ammonia borane (AB) at room temperature. Rh-0/Co3O4 nanoparticles with 0.5% wt Rh loading provide a turnover frequency of 1800 min(-1) and a total of 1.02 x 10(6) turnovers for H-2 evolution from the hydrolysis of AB at 25.0 +/- 0.1 degrees C. This turnover frequency is the second best value ever reported for the hydrolysis of AB, and the total turnover number of over a million is a record lifetime ever reported. Magnetically separable rhodium(0) nanoparticles are expectedly highly reusable catalysts and preserve their initial activity after the fifth run of hydrolysis. We also report the results of our study on the catalytic activity of Co3O4 nanopowders for the same dehydrogenation reaction.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING

Suggestions

Magnetically separable transition metal nanoparticles as catalysts in hydrogen generation from the hydrolysis of ammonia borane
Özkar, Saim (2021-06-15)
Hydrogen Energy Publications LLCIt reviews the available reports on the preparation and use of magnetically separable transition metal nanoparticles (TMNs) as reusable catalysts for the hydrolytic dehydrogenation of ammonia borane (AB). After a short introduction, the review starts with the papers on the employment of intrinsically magnetic TMNs as catalysts for releasing H2 gas from AB, which includes colloidal nanoparticles of intrinsically magnetic metals, TMNs in combination with materials having large ...
Ceria supported rhodium nanoparticles: Superb catalytic activity in hydrogen generation from the hydrolysis of ammonia borane
Akbayrak, Serdar; Tonbul, Yalcin; Özkar, Saim (2016-12-05)
We investigated the effect of various oxide supports on the catalytic activity of rhodium nanoparticles in hydrogen generation from the hydrolysis of ammonia borane. Among the oxide supports (CeO2, SiO2, Al2O3, TiO2, ZrO2, HfO2) ceria provides the highest catalytic activity for the rhodium(0) nanoparticles in the hydrolysis of ammonia borane. Rhodium(0) nanoparticles supported on nanoceria (Rh-0/CeO2) were prepared by the impregnation of rhodium(III) ions on the surface of ceria followed by their reduction ...
Cobalt ferrite supported platinum nanoparticles: Superb catalytic activity and outstanding reusability in hydrogen generation from the hydrolysis of ammonia borane
Akbayrak, Serdar; Özkar, Saim (2021-08-15)
In this work, platinum(0) nanoparticles are deposited on the surface of magnetic cobalt ferrite forming magnetically separable Pt-0/CoFe2O4 nanoparticles, which are efficient catalysts in H-2 generation from the hydrolysis of ammonia borane. Catalytic activity of Pt-0/CoFe2O4 nanoparticles decreases with the increasing platinum loading, parallel to the average particle size. Pt-0/CoFe2O4 (0.23% wt. Pt) nanoparticles have an average diameter of 2.30 +/- 0.47 nm and show an extraordinary turnover frequency of...
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...
Hydrolytic dehydrogenation of ammonia borane catalyzed by reduced graphene oxide supported monodisperse palladium nanoparticles: High activity and detailed reaction kinetics
Kilic, Buket; Sencanli, Selin; Metin, Onder (2012-09-01)
A highly active and stable catalyst for the hydrolytic dehydrogenation of ammonia borane (AB) was prepared by supporting monodisperse palladium nanoparticles (Pd NPs) on reduced graphene oxide (RGO) via a facile method. RGO was prepared via modified chemical route and used as support matrices for monodisperse Pd NPs that were formed by the reduction of palladium(II) acetylacetonate by borane tert-butylamine complex in the presence of oleylamine. RGO supported Pd NPs (RGO@Pd) show high activity and stability...
Citation Formats
S. Akbayrak, Y. Tonbul, and S. Özkar, “Magnetically Separable Rh-0/Co3O4 Nanocatalyst Provides over a Million Turnovers in Hydrogen Release from Ammonia Borane,” ACS SUSTAINABLE CHEMISTRY & ENGINEERING, pp. 4216–4224, 2020, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/37208.