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

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

Abstract

The substituted iron–thiolate complex [Fe₂(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 4×10⁶ 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.

Iron brew: [Fe₂(μ-bdt)(CO)₄{P(OMe)₃}₂] (bdt=benzenedithiolate) catalyzes electrochemical hydrogen production in an aqueous micellar solution (see scheme). It achieves a turnover frequency of 4400 s⁻¹ at a potential less negative than −0.6 V (versus a standard hydrogen electrode) at pH 3.