Catalytic activity of thiourea and its selected derivatives on electroreduction of In(III) in chlorates(VII)

摘要

It was found that thiourea, N-methylthiourea, N,N'-dimethylthiourea and N-allylthiourea accelerate the electroreduction process of In(III) ions in chlorates(VII). These substances are adsorbed on mercury from chlorates(VII). The relative surface excesses of thiourea and its derivatives increase with the increase of their concentrations and electrode charge. After adding thiourea, N-methylthiourea, N,N'-dimethylthiourea and N-allylthiourea to the solution an acceleration of the electroreduction process of In(III) ions occurs. This process depends on two factors: the adsorption of an accelerating substance on mercury and on the formation of complexes between a depolarizer and an accelerating substance on the electrode surface. The equilibrium of this complexing reaction determines the magnitude of the catalytic effect.