Catalytic Polarographic Wave of Fe(II) in Neutral Thiocyanate Solutions at Dropping Mercury Electrode

Article abstract of DOI:10.1246/bcsj.54.1715

The electrochemical behavior of Fe(II) in neutral thiocyanate solutions has been investigated at a dropping mercury electrode (DME).It was found that Fe(II) in neutral thiocyanate solutions gave a catalytic polarographic wave at potentials prior to the main Fe(II) reduction wave.The mechanism of the catalytic process involves the chemical reduction of thiocyanate ions with Fe(OH)2,aq at the electrode surface.Controlled potential electrolysis suggests that the reduction of thiocyanate ions proceeds with the formation of sulfide and cyanide ions.Sulfide ions produced at the electrode surface can react with Fe(II) diffusing to the electrode to form FeS.The discharge of this is responsible for the catalytic current, while cyanide ions have no essential role in the catalytic process.The effects of surface active substances and iodate ions on the catalytic wave are also discussed.