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Improvement of the catalytic properties of Ti-doted Raney-Nickel for H2-Anodes of alkalione fuel cells by Ni(OH)2-surface coating |
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| Authors: | H Ewe E W Justi H -J Selbach |
| Affiliation: | a FH Hamburg, Lohbrügger Kirchstraβe 65, D-2050, Hamburg 80, F.R.G. b TU Braunschweig, Physikzentrum, Mendelssohnstr. 2, D-3300, Braunschweig, F.R.G. |
| Abstract: | This paper belongs to a series of three dealing with the latest improvements in the alkaline H2---O2 fuel cells operating under mild conditions thanks to their Raney-Ni-catalysts. The first of these papers describes the benefication of a Ni(OH)2 surface coating on the catalytic activity of Ti-doted Raney-Ni in supported electrodes. This Ni(OH)2 surface coating is produced by carefully optimized oxidation. A Ni(OH)2-content of 5 up to 6wt% increases the attainable current density by the factor 3–4. In addition, the exchange current density is markedly enlarged up to a Ni(OH)2-fraction by 5%, but remains unchanged when further increasing the Ni(OH)2 percentage. Thus, one may conclude that the Ni(OH)2 surface coating improves markedly the charge exchange reaction. On the other side, the surface diffusion of H-atoms on the pore walls to the location of charge exchange reaction is hindered by too much Ni(OH)2. |
| Keywords: | Fuel cells Alkaline aqueous electrolyte Raney-nickel Supported electrodes Mild operating conditions |
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