Mechanistic and kinetic study of carbon tetrachloride reduction at nickel surfaces

There has been considerable interest in developing destructive treatment methods for removing chlorinated organic solvents from contaminated waters. A study investigated the mechanism and kinetics of carbon tetrachloride (CT) reduction at nickel cathodes. Either competition between CT molecules for reactive sites on the electrode surface, or adsorption of CT onto the electrode followed a nonlinear isotherm. The rates of subsequent reaction steps did not affect the overall rate of hydrogen evolution. Transfer of the first electron to a CT molecular was the rate-limiting step for CT reduction to CH₄. The rate-limiting step for complete CT dechlorination to CH₄ involved an outer sphere electron transfer.