Hydrogen generation from hydrolysis of ammonia-borane using Pd-PVB-TiO2 and Co-Ni-P/Pd-TiO2 under stirred conditions

Rakap, Murat
Kalu, Egwu Eric
Özkar, Saim
The employment of Pd-PVB-TiO2 and Co-Ni-P/Pd-TiO2 in hydrogen generation from the hydrolysis of ammonia-borane (H3NBH3, AB) under stirred conditions are reported. Both catalysts are found to be highly active, isolable, and reactivatable in the hydrolysis of ammonia-borane even at low concentrations and temperature. The Arrhenius activation energies were found to be 54.9 and 54.7 kJ mol(-1) for the hydrolysis of ammonia-borane catalyzed by Pd-PVB-TiO2 and Co-Ni-P/Pd-TiO2, respectively. Maximum hydrogen generation rates in the hydrolysis of AB catalyzed by the Pd-PVB-TiO2 catalyst (1.5 mM) are 1910 and 14,800 mL H-2 min (g Pd)(-1) at 25 and 55 +/- 0.5 degrees C, respectively. The maximum hydrogen generation rates are 170 and 1390 mL H-2 min(-1) (g catalyst)(-1) for the hydrolysis of AB catalyzed by Co-Ni-P/Pd-TiO2 (25 mg) at 25 degrees C and 55 +/- 0.5 degrees C, respectively. In comparison to unstirred conditions, these results demonstrate that a significant external mass transfer resistance caused by the desorbed metaborate by-products exist in the under unstirred conditions.


Hydrogen generation from the hydrolysis of sodium borohydride by using water dispersible, hydrogenphosphate-stabilized nickel(0) nanoclusters as catalyst
Metin, Oender; Özkar, Saim (Elsevier BV, 2007-08-01)
Water-dispersible nickel(0) nanoclusters are prepared from the reduction of nickel(II) acetylacetonate by sodium borchydride in aqueous solution and stabilized by hydrogerphosphate anion. Hydrogenphosphate-stabilized nickel(0) nanoclusters were characterized by using XPS, FT-IR, UV-Vis and NMR spectroscopic methods. As the first example of water-dispersible nickel(0) nanoclusters, they were employed as catalyst in the hydrolysis of sodium borohydride. Hydrogenphosphate-stabilized nickel(0) nanoclusters were...
Pt-based electrocatalysts for polymer electrolyte membrane fuel cells prepared by supercritical deposition technique
Bayrakceken, Ayse; Smirnova, Alevtina; Kitkamthorn, Usanee; Aindow, Mark; Turker, Lemi; Eroğlu, İnci; Erkey, Can (Elsevier BV, 2008-05-01)
Pt-based electrocatalysts were prepared on different carbon supports which are multiwall carbon nanotubes (MWCNTs), Vulcan XC 72R (VXR) and black pearl 2000 (BP2000) using a supercritical carbon dioxide (ScCO2) deposition technique. These catalysts were characterized by using X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM) and cyclic voltammetry (CV). XRD and HRTEM results demonstrated that the ScCO2 deposition technique enables a high surface area metal phase to be deposit...
Photogalvanic effect in aqueous Methylene blue nickel mesh systems: Conversion of light into electricity
Bayer, IS; Eroğlu, İnci; Turker, L (Wiley, 2001-03-10)
The photogalvanic effect in electrochemical cells, employing aqueous Methylene blue and Fe(II)/Fe(III) couple electrolyte and nickel-mesh electrodes, were experimentally investigated. Five different standard H-cell configurations were set-up by modifying the electrolyte. Long-term open-circuit Voltage measurements were conducted in order to test the stability of the cells. Light on-off reproducibility experiments were also carried out during lengthy cell operations. By comparing experimental quantum yield w...
Enhanced capacitive behaviour of graphene based electrochemical double layer capacitors by etheric substitution on ionic liquids
Siyahjani, Shirin; Oner, Saliha; Diker, Halide; GÜLTEKİN, BURAK; Varlikli, Canan (Elsevier BV, 2020-08-01)
In this study, we report the effect of etheric substituents in imidazolium and ammonium based ionic liquids (IL) on the performance of electrochemical double layer capacitors (EDLC) consisted of gel polymer electrolyte (GPE) and reduced graphene oxide (RGO) electrode. GPEs contain poly (vinylidene fluoride-hexafluompropylene) (PVDF-HFP) and the ILs. Ammonium and imidazolium based ionic liquids (ILs) differ by their length of etheric groups and etheric group contents, respectively. According to the cyclic vo...
Hydrogen generation from the hydrolysis of ammonia borane using cobalt-nickel-phosphorus (Co-Ni-P) catalyst supported on Pd-activated TiO2 by electroless deposition
Rakap, Murat; Kalu, Egwu Eric; Özkar, Saim (Elsevier BV, 2011-01-01)
Catalytically active, low-cost, and reusable transition metal catalysts are desired to develop on-demand hydrogen generation system for practical onboard applications. By using electroless deposition method, we have prepared the Pd-activated TiO2-supported Co-Ni-P ternary alloy catalyst (Co-Ni-P/Pd-TiO2) that can effectively promote the hydrogen release from ammonia-borane aqueous solution. Co-Ni-P/Pd-TiO2 catalysts are stable enough to be isolated as solid materials and characterized by XRD, SEM, and EDX. ...
Citation Formats
M. Rakap, E. E. Kalu, and S. Özkar, “Hydrogen generation from hydrolysis of ammonia-borane using Pd-PVB-TiO2 and Co-Ni-P/Pd-TiO2 under stirred conditions,” JOURNAL OF POWER SOURCES, pp. 184–190, 2012, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/37998.