The electrocatalytic reduction of nitrogen compounds. Part I.The electrochemical reduction of nitrite at a rotating platinum ring-disk electrode

The mechanism of the electrochemical reduction of nitrite has been studied at a rotating ring-disc electrode. It is found that the reduction of nitrite to nitric oxide is a reversible process. The reduction of nitric oxide to hydroxylamine involves the intermediate HNO, from which dinitrogen oxide can be formed in a side reaction to the reduction process

Electrochemical behaviour of cytochrome c at low potentials

d.c. polarograms of bovine heart cytochrome c show reduction currents at low potentials. This is observed in buffer solutions with pH values between 1 and 10.5. These currents are attributed to catalytic hydrogen formation (pre-sodium currents). After succinylation of the protein, the current in glycine-NaOH buffer of pH 10.5 disappears almost completely, whereas that in acetate buffer of pH 4.5 is affected only slightly. It is concluded that different groups are responsible for the currents observed in these two buffer

Zinc electrode shape change I. In situ monitoring

Zinc electrode shape change, the redistribution of zinc material over the electrode during repeated cycling, has beenidentified as one of the main life-limiting factors for alkaline nickel oxide/zinc secondary batteries. To investigate this phenomenon in situ, a radiotracer, 65Zn, is incorporated in the battery and its movement monitored during repeated cycling ofthe battery. The changes in the distribution of 65Zn over the electrode during battery operation are attributed to the displacement of radioactive zincate ions via the battery electrolyte. It is shown that the spatial distribution of 65Zn offers areliable indication for the zinc material distribution over the electrode, provided an electrode with uniformly specific radioactivity is used in the measurements. Radiotracer experiments using zinc electrodes containing 2 weight percent HgOas an additive and uniformly labeled with 203Hg, have revealed that during battery cycling no substantial net transport ofmercury species occurs. It is concluded that it is highly unlikely that the mercury additive detaches from or moves overthe zinc electrode surface during the cycling process. Also, these experiments show that zinc material transport as a resultof detachment of electrode mass did not occur