The Corrosion of Carbon Black Anodes in Alkaline Electrolyte: I . Acetylene Black and the Effect of Cobalt Catalyzation

Abstract

14 c labeling of acetylene black was used together with mass spectroscopic analysis of the gas evolved to determine the current efficiencies for oxygen evolution, carbon dissolution, and carbon gasification (to carbon monoxide}. The current efficiencies were found to depend dramatically on potential, temperature and the presence of an evolution catalyst like Co 3 o 4 . On uncatalyzed black, three regimes could be distinguished: I. -at potentials below 500 mV vs. Hg/HgO and temperatures below 50°C, carbon dissolution is the primary anodic process; II. -at 500-600 mV and 50°C or lower, carbon dissolution and oxygen evolution occur at equivalent rates; III. -above ca. 600 mV or above ca. 60°C oxygen

Limiting behaviour during the hydroperoxide ion generation in a flow alkaline fuel cell

“…It was further submitted to cyclic polarisation at 100 mV s À1 up to a stationary profile, taking its ocp as the lower limit. The upper limits were 0.36 and 0.45 V for 1.0 and 6.0 M KOH, respectively, to avoid carbon oxidation in such media [24]. Pure H 2 was then injected into the anode to reach the corresponding equilibrium potential and afterwards, positive linear sweep voltammograms starting at this potential were recorded at 1 mV s À1 with ohmic drop correction.…”

Preparation and characterization of Nb-doped TiO2 nanoparticles used as a conductive support for bifunctional CuCo2O4 electrocatalyst

“…Cyclic voltammograms (CVs) were recorded in a 1 M KOH solution between À0. 2 [11] composite electrodes. The last value was obtained considering that Vulcan XC72R and spinel oxide, which possess different reference capacitances, are both electroactive in the potential range investigated in this work.…”

“…Also, it has been well demonstrated that whereas the current efficiency for oxygen evolution of a cobalt oxide-catalyzed acetylene black electrode is increased severalfold relative to that for the uncatalyzed black sample, the rates of the corrosion processes are also accelerated [2,3]. Therefore, the development of a more anodically stable catalyst support is mandatory for rechargeable metal-air batteries.…”

Magneli phase Ti4O7 electrode for oxygen reduction reaction and its implication for zinc-air rechargeable batteries

“…Under these conditions, the kinetically slow but thermodynam-ically favoured carbon oxidation into carbonate during battery operation can proceed [4]. Ross and Sokol [5] studied this corrosion process in alkaline solutions using 14 C labelling technique, and found that oxidative carbon dissolution and gasification (to carbon monoxide) occurred at different temperatures and applied potentials. Impedance analysis of rechargeable metal-air batteries also showed that electrode deterioration during anodic oxygen evolution was mainly due to carbon corrosion, resulting in a loss in electrochemical active surface area [1].…”