A wide compositional range of unsupported platinum-ruthenium alloy catalysts were prepared by thermal decomposition of the chlorides and chloroacids. The electrocatalysts were characterized by cyclic voltammetry x-ray diffraction, and energy-dispersive x-ray spectroscopy. The BET surface area of the electrocatalysts increases with increasing Ru content up to -70 atomic percent (a/o) and then reaches a plateau value. Electrodes fabricated from the electrocatalysts were also evaluated as anodes for methanol electro-oxidation in sulfuric acid over a range of temperatures. Unlike the situation for pure Pt, Ru is inactive for methanol electro-oxidation at 25°C but becomes active at higher temperatures. The peak current observed during an anodic potential scan gradually shifts to more cathodic potentials with increasing temperature. When a comparison is made on the basis of electrode geometric surface area, a -50 a/o ruthenium electrocatalyst provides the highest activity for methanol electro-oxidation at both 25 and 60°C. The methanol electro-oxidation rate is 0.5 orders with respect to methanol concentration (between 0.1 and 2 M) for the Pt-Ru (-50:50) electrode.
Using a rotating Pt electrode, the simultaneous electro-oxidation of methanol and electroreduction of O2 was studied in O~ saturated 0.5M H2SO4 solutions containing dissolved methanol. The two processes occurred with no apparent interaction above 0.8 V vs. a reversible H~ electrode. At potentials below 0.8 V the net oxidation/reduction current is smaller (i.e., less cathodic) than would be expected if the reactions occurred with no interaction. The evidence suggests that the effect is due to partial poisoning of the O~ reduction process by adsorbed methanol. At sufficiently low potentials (~0.4 V), O2 electroreduction reaches the same diffusion-limited
This paper describes a study of room temperature lithium cells employing solutions of
LiBCl4
in
POCl3
and
LiAlCl4
in
SOCl2
as electrolytes and polytetrafluoroethylene (Teflon)‐bonded carbon black electrodes as cathodes. A novel feature of these cells is that during discharge the solvents, i.e.,
POCl3
and
SOCl2
, are electrochemically reduced and behave as soluble cathodes. Sealed prototype cells were fabricated using a polyethylene‐polyester laminated bag container. Based on total cell weight, a prototype cell yielded an experimental energy density of 244 W‐hr/lb for a 57‐hr discharge rate (20 mA constant current; 1 mA/cm2 current density). The performance of these cells is also compared with the performance of prototype lithium‐organic electrolyte‐graphite monofluoride and lithium‐inorganic electrolyte‐tetracarbon monofluoride cells.
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