| 摘要 |
1,158,580. Fuel cell electrode having a carbon fabric support. INSTITUT FRANCAIS DU PETROLE, DES CARBURANTS ET LUBRIFIANTS. 14 Dec., 1966 [16 Dec., 1965], No. 56036/66. Heading H1B. A fuel cell electrode comprises a thin support formed by a fabric of carbon threads covered on at least one surface by a fritted mixture of a polymer and a catalytic material. Preferably there are, per square metre of fabric surface, 0À1-300 gm. of catalyst (calculated as metal) and 0À05-100 gm. of polymer, corresponding to 0À1-60 wt. per cent and 0À05-20 wt. per cent respectively of the total electrode. Suitable fabrics are obtained by heating, out of air, at e.g. 600-900‹ C. fabrics of, e.g. flax, jute, cotton, regenerated cellulose, cellulose acetate, polyethylene terephthalate or polycaprolactam, giving fabrics having at least 5 meshes per cm. and a thickness below 2 mm., the fibrillae of the threads having a diameter less than 50 Á. Suitable catalysts include Co, Ni, Ru, Rh, Pd, Os, Ir, Pt, Cu, Ag and Au as metals, e.g. metal blacks or Raney metals, or oxides, carbonates, hydroxides, sulphides, selenides, tellurides, borides, molybdates, tungstates, vanadates and chromites. Suitable polymers include PTFE, polytrifluorochloroethylene, polyhexafluoropropylene, polyethylene, polypropylene, polytrifluoroethylene and fluoro-olefin copolymers, of softening points above 75‹ C. The catalyst and polymer may be applied from aqueous dispersions containing 0À1-30 wt. per cent and 0À1-60 wt. per cent of these, respectively. There may also be present dispersing or swelling agents, e.g. polyethylene oxide, polypropylene oxide, carboxymethylcellulose or polyvinyl alcohol, and carriers for the catalyst, e.g. carbon, graphite or non- catalytic Ag or Ni. In examples a graphite fabric is treated with aqueous dispersions of (1) platinum black, colloidal silica, and PTFE, (2) platinum-bearing carbon (5 wt. per cent Pt), polyvinyl alcohol and PTFE, (3) silver oxide, colloidal silica, polyvinyl alcohol and PTFE, and (4) 1-5 Á particle size graphite powder, colloidal silver, polvinyl alcohol and PTFE/ polyhexafluoropropylene copolymer, then heated at 300‹ C. in H 2 /N 2 (250‹ C. in N 2 in Example 4). The products are tested as hydrogen electrodes and as oxygen electrodes in semicells using H 2 SO 4 and KOH electrolytes. |
