A Binuclear Iron–Thiolate Catalyst for Electrochemical Hydrogen Production in Aqueous Micellar Solution

The substituted iron-thiolate complex [Fe(2)(μ-bdt)(CO)(4){P(OMe)(3)}(2)] (bdt=benzenedithiolate) is an active catalyst for electrochemical hydrogen production in aqueous sodium dodecyl sulfate solution, with a high apparent rate constant of 4×10(6) M(-1) s(-1). The half-peak potential for catalysis of proton reduction is less negative than -0.6 V versus the standard hydrogen electrode at pH 3. Voltammetric data are consistent with the rate of electrode reaction controlled by diffusion. A mechanism that begins with the rapid protonation of the iron-thiolate catalyst is proposed. The Faradaic efficiency in diluted HCl solutions is close to 100%, but the catalytic activity decayed after about twelve turnovers when electrolysis was carried out in the presence of acetic acid.