Proton Hopping Mechanism Research Articles

The electrochemistry of iron in methanolic solutions and its relation to corrosion

The corrosion behavior of iron in methanol, its dependence on the presence of low levels of aggressive species, and an interpretation of these dependencies on the basis of the electrochemical reactions occurring have been determined. A quantitative analysis of the phenomenology of the corrosion behavior due to low (mM) levels of acid, chloride and sulfate has shown that the dominant first order effects are the increase in corrosion rate and elevation in corrosion potential due to the addition of acid. The dominant second order interaction between species is the inhibition of the acid effect on corrosion rate by the simultaneous addition of water. A study of the nature and kinetics of the cathodic reactions relevant to the corrosion of iron in methanol showed that inhibition of corrosion by water is primarily due to the decrease in the mobility of the proton with increasing water content. This inhibition of corrosion occurs by hindrance of the proton hopping mechanism due to preferential protonation of water vs methanol.

The study of hydronium NASICON conductivity with deuterium

The ionic conductivity of the bulk phase of bonded hydronium NASICON (Hyceram TM) was measured at equilibrium with an H 2O/N 2 and then a D 2O/N 2 atmosphere, each at 100% relative humidity and 75% relative humidity over the temperature range 25°C to 50°C. At 100% relative humidity and 25°C, the protonic system had a bulk conductivity of 5.0×10 −4 S cm and an activation energy of 17.3 kJ mole ; the same sample, when deuterated, had a bulk conductivity of 2.2×10 −4 S cm and an activation energy of 19.3 kJ mole . At 75% relative humidity and 25°C, the conductivity of the protonated system decreased to 1.4×10 −4 S cm with an activation energy of 24.1 kJ mole . The deuterated sample at 75% relative humidity had a bulk conductivity of 5.4×10 −5 S cm with an activation energy of 26.0 kJ mole . The isotope effect suggested a proton hopping (Grotthus) mechanism as the means by which the protons pass through the lattice.