Studies on the electrochemical formation and reduction of surface oxide at platinum electrodes have been carried out with particular reference to polarization and hysteresis effects in these processes. Comparisons between the results of galvanostatic and potential sweep techniques have been made for three types of surfaces of platinum electrodes prepared by: (a) heating in hydrogen; (6) heating in a flame; and (c) electrolytically forming platinum black surfaces. The dependence of the quantity of reducible oxide formed under prior steady-state potentiostatic conditions has been related to potential and time of anodic polarization. Polarization effects in the reduction of the surface oxide have been evaluated in terms of the potential dependence of the pseudocapacitance maximum for the oxide reduction process, and a mechanism for the reduction is suggested. The relative slowness of the reduction process is important in regard to the question of the role of oxide in the kinetics of electrocatalytic oxidations at platinum anodes. Hysteresis effects in anodic formation and cathodic reduction of the oxide are discussed in terms of a totally irreversible phase transition involving the ad-layer.
of nitroammine complexes of Co(III) to polystyrenesulfonate were also studied, and the extent of binding was found to be much lower than with the phen complexes and to decrease with decreasing charge of the complex; the Co(en)2pyN022+ and particularly the Co(bipy)2(N02)2+ complex were much more strongly bound, suggesting that the existence of van der Waals forces or hydrophobic bonding18 was more important than purely coulombic effects. Binding of phen complexes to the polymethacrylate anion was found to be considerably weaker than to the polystyrenesulfo-nate anion, as expected. Our results indicate that hydrophobic bonding is not an important factor in PVI • Cu(II) • NTA complexes.
The efficiency of the method of de‐aerating aqueous solutions devised by Hersch has been examined. The method is more convenient and efficient than those in current use, because within 1 h. the residual oxygen content of a solution can be reduced either to 0.003 ± 0.001 p.p.m. by weight by use of ‘White Spot’ nitrogen (less than 10 p.p.m. of oxygen) as the scrubbing gas, or 0.0005 p.p.m. when purifited nitrogen is used.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.