Electrocatalysts containing iridium and platinum‐iridium alloys have shown very encouraging levels of performance when used as anodes in ammonia fuel cells. These materials were appreciably more active than platinum alone, and the open‐circuit voltage and polarization under load generally improved with increasing iridium content. Data are presented for ammonia/oxygen cells at 100°–120°C using 54% potassium hydroxide as electrolyte and platinum ‐iridium blacks and Pt/Ir supported on boron carbide and graphite as anodes. The observed electrochemical activity of iridium appears to be related to the unique activity of this metal in the gas phase catalytic decomposition of ammonia. Supported iridium catalysts were also found to be effective in an external cracking unit maintained at 350°–450°C and coupled to a hydrogen fuel cell system. In this case enhanced performance was observed when small amounts of oxygen were introduced with the ammonia into the catalytic reactor.

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The rate of adsorption of propane on platinum in 37 m/o HF at 30~ has been measured using single linear voltage sweep techniques as a complement to earlier studies at 90~ The surface coverage by hydrocarbon species was measured as a function of adsorption time and potential. The rate of adsorption follows Langmuir kinetics with a third-order dependence on free surface. The rate of reaction of the initial adsorbate at 90~ to form a highly electroactive species (type I) was also measured, and found to be proportional to the surface coverage of the initial adsorbate (type II) and the square of the fraction free surface. The subsequent rate of electrochemical oxidation of type I was proportional to the surface coverage of type I and to free surface. Values for the kinetic parameters are reported, and the results are discussed in terms of a proposed mechanism for the over-all oxidation process.

An Ru‐4% Ir alloy electrodeposit alone on titanium demonstrated excellent activity for the oxygen evolution reaction, but had insufficient life to make it economical to use for nickel electrowinning at 70°C. However, precious metal interlayers were found to extend the life of the Ru‐Ir coating in a simulated nickel‐electrowinning test so that it surpassed the cost and life targets initially set for it, and made it economical to use at all electrowinning temperatures up to 70°C. Top layers of RuO2 suppress the initial preferential dissolution of Ru from the Ru‐Ir alloy at very high current densities but with some sacrifice in service life. Several of the multilayered precious metal coatings for titanium investigated here can reasonably be expected to operate efficiently as an anode for nickel electrowinning for at least 20,000 hr at practical operating current densities.