The Decomposition of Argentic and Argentous Oxides in Concentrated Koh Electrolyte

The Decomposition of AgO in Alkaline Solutions

“…Figure 4 reveals also the known temperature dependence of the gassing rate in alkaline solutions (1,3,(5)(6)(7)(8); the gassing rate increased with increasing temperature. The rate constants, k in various NaOH solutions were calculated by the half-life method from r42 and rx, the gassing rate at the longest available time (x ~--42 hr).…”

“…The stability of AgO seems to depend on its mode of preparation (9) and the various AgO samples were found to decompose at different rates (1,5,7). Unoxidized silver metal increased the rate of decomposition of AgO (3,7) whereas Ag20 did not affect the stability of AgO (3).…”

“…Oxygen overvoltage of the local cell action and formation of a protective Ag~O film on the AgO is thought to be the reason for its metastability (1,3). The decomposition of AgO (a) is light sensitive (4, 1), (b) increases with increasing temperature (1,3,(5)(6)(7)(8), and (c) increases with increasing KOH concentration (1,7,8). The decomposition of "Ag20~" (a reaction product of AgNO3 and K2S2Os) in KOH (< 1N) was found by Stehlik (6) to be a first order reaction with an activation energy of 22 kcal/mole.…”

“…The addition of A12Oz to alkaline electrolytes is said (12) to inhibit the oxygen evolution. The addition of ZnO to KOH electrolytes decreases the decomposition rate of AgO to Ag20 (1,5) and prevents the reduction of Ag20 to Ag (5). According to Amlie and Rfietschi (1), the addition of zincate ions has little influence because the addition of ZnO to KOH electrolyte reduces its OH-activity and this causes the decrease of the decomposition rate.…”

Thermogravimetric Analysis of Silver Oxide Mixtures

“…In the gasometric method, proposed by F. M. Bowers, et al, 5 the oxygen evolved upon isothermal decomposition of the oxides is measured at four different temperatures. Other electrochemical methods such as coulometric titration have been suggested.…”