Kinetics of Sodium Borohydride Hydrolysis at the Cobalt with a Fiber Structure Modified with Gold Nanoparticles

Among chemical hydrides sodium borohydride is widely used as a source for a hydrogen generation during its catalytic hydrolysis. This attention is determined by its features such as a high hydrogen storage capacity, nontoxicity, good storability, easily controlled hydrogen generation rate. The development of new catalysts with high activity in the hydrolysis reaction of borohydride and durability plays an important role in the hydrogen generation for fuel cells.

This work presents the study of catalytic activity of cobalt with a fiber structure deposited on the copper surface and modified with gold nanoparticles towards the hydrolysis of borohydride. Cobalt coatings with the thickness of ~3 µm were deposited from the electrolyte described in Ref. [1]. Au crystallites were deposited on the Co/Cu surface (denoted as Au(Co)/Cu) via the galvanic displacement technique. The Co/Cu catalysts were immersed into the 1 mM HAuCl₄ + 0.1 M HCl solution at 25 ^oC for 0.5, 1 and 5 min, respectively [2]. The morphology, structure and composition of the prepared catalysts were examined by means of Field Emission Scanning Electron Microscopy, Energy Dispersive X-ray Spectroscopy, X-ray diffraction and Inductively Coupled Plasma Optical Emission Spectroscopy.

It has been determined that the Au loadings were 10.8, 22.4 and 84.4 µg cm^-2 in the prepared Au(Co)/Cu catalysts after the immersion of Co/Cu into the gold-containing solution for 0.5, 1 and 5 min, respectively. The data of hydrogen generation from an alkaline sodium borohydride solutions using the Co/Cu and different Au(Co)/Cu catalysts under various conditions are presented.

It has been determined that the temperature and amount of catalysts have exceptional influence on the rate of hydrogen generation from alkaline sodium borohydride solutions.

 References

 [1] E. Juzeliunas, S. Lichusina. Patent of the Republic of Lithuania No. 5481 26.03.2008.

[2] L. Tamasauskaite-Tamasiunaite, A. Jagminiene, A. Balciunaite, A. Zabielaite, J. Vaiciuniene, A. Selskis, R. Juskenas, E. Norkus. Int. J. Hydrogen Energy 38 (2013) 14232-14241.