WATER-ELECTROLYSIS CELLS USING HYDROGEN-DIFFUSION CATHODES
Abstract
A matrix based on diamond powder was satisfactory for extended use over 200 C electrolyte temperature in oxygen-generating electrolysis cells using Pd-25Ag hydrogen diffusion cathodes and operating on a water-vapor feed. Over 2500 hours of essentially 100% hydrogen transmission was demonstrated with a small experimental cell containing: 6.35 mm OD x 0.13 mm wall Pd-25Ag tube cathode; platinum screen anode; 250-420 micron-size diamond powder matrix initially impregnated with 80 wt % sodium hydroxide electrolyte. The cell was evaluated in an experimental unit that maintained the cell temperature at 210 plus or minus 4 C and the water-vapor generator at 78 C to provide a water-vapor feed at 340 mm Hg partial pressure for operation at 37 ma/cu cm cathode current density with a cell voltage of 1.54 volts. A separate evaluation of Pd-25Ag cathode alone in a free-electrolyte at 145 C and 37 ma/cu cm was extended to over 16,000 hours of satisfactory performance for hydrogen diffusion. Experiments on the use of phosphoric acid electrolyte was Pd-25Ag cathodes at 37 ma/cu cm showed that satisfactory hydrogen diffusion was limited to about 45 hours and could be attributed to contamination resulting from anodic corrosion of platinum anodes at 80 C in 85 wt % H3PO4.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1969
- Accession Number
- AD0691464
Entities
People
- Edwin C. Kolic
- John E. Clifford
Organizations
- Battelle Memorial Institute