Web Release Date: January 5,
A New Class of Efficient Electrocatalysts for the Reduction of Protons into Hydrogen Based on the [Mo2O2S2]2+ Building Block
and
Laboratoire de Chimie Physique, UMR 8000, Université de Paris-Sud, bât. 349, 91405 Orsay Cedex, France, Institut Lavoisier de Versailles, UMR 8180, Université de Versailles, 45 avenue des Etats Unis, 78035 Versailles, France, and Laboratoire de Chimie Quantique, Institut de Chimie-UMR 7177, Centre National de la Recherche Scientifique, Université Louis Pasteur, 4 rue Blaise Pascal, 67000 Strasbourg, France
Received: September 14, 2007
In Final Form: October 22, 2007
Abstract:
Oxothiomolybdenum wheels represent a new family of efficient electrocatalysts for the reduction of protons into hydrogen. The present study focuses on the complex [Mo8S8O8(OH)8(Ox)]2- (1) as a lithium salt (Ox2- = oxalate), which exhibits an electrocatalytic reduction wave of protons in the presence of perchloric acid at about -1.00 V versus SCE in DMF. Efficiency of this new electrocatalyst was evidenced by cyclic voltammetry and coulometry. DFT calculations were reported and bring about data of the protonated state of the catalyst, the first step of the postulated mechanism in the catalytic reaction. Other weak acids such as p-toluenesulfonic acid, trifluoroacetic acid, and acetic acid in DMF were tested and found to be efficient for the reduction of protons. The complex [Mo12S12O12(OH)12(Trim)]3- (2) behaves also as an electrocatalyst, functioning at a very low overpotential. Finally, the biomimetic behaviors of this new class of efficient electrocatalysts for hydrogen production mimic those of hydrogenases and compare favorably with their performances.
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