Hydrogen Evolution by FeIII Molecular Electrocatalysts Interconverting between Mono and Di-Nuclear Structures in Aqueous Phase

Mirko Tagliapietra; Andrea Squarcina; Neal Hickey; Rita De Zorzi; Silvano Geremia; Andrea Sartorel; Marcella Bonchio

doi:10.1002/cssc.201701612

Hydrogen Evolution by Fe^III Molecular Electrocatalysts Interconverting between Mono and Di-Nuclear Structures in Aqueous Phase

ChemSusChem. 2017 Nov 23;10(22):4430-4435. doi: 10.1002/cssc.201701612. Epub 2017 Nov 9.

Authors

Mirko Tagliapietra¹, Andrea Squarcina¹, Neal Hickey², Rita De Zorzi², Silvano Geremia², Andrea Sartorel¹, Marcella Bonchio¹

Affiliations

¹ Department of Chemical Sciences, ITM-CNR University of Padova, Via Marzolo 1, 35131, Padova, Italy.
² Department of Chemical and Pharmaceutical Sciences, University of Trieste, Via Licio Giorgieri 1, 34127, Trieste, Italy.

PMID: 29096041
DOI: 10.1002/cssc.201701612

Abstract

A new FeL/Fe₂ L₂ manifold, with HL=2-({[di(2-pyridyl)methyl](methyl)amino}methyl)phenol, was prepared in gram scale (>50 % yield) and characterized in solution and solid state. The monomer/dimer interconversion is controlled in aqueous phase, upon varying the pH conditions. The electrocatalytic hydrogen evolution reaction (HER) occurs through the FeL monomer with added trifluoroacetic acid (TFA) and through the Fe₂ L₂ μ-oxo dimer in acetate buffer (pH 4.9), with an overpotential of about 1 V and faradaic yield up to 75 %. The resulting i_cat /i_p values in the range 15-28 are among the highest reported for Fe-based electrocatalysts (i_cat is the catalytic current, whereas i_p is the current of an Fe-based redox event).

Keywords: electrocatalysis; hydrogen evolution; iron complexes; polypyridine ligands; water reduction.