Catalytic Activity of an Iron-Based Water Oxidation Catalyst: Substrate Effects of Graphitic Electrodes

Konstantin G Kottrup; Silvia D'Agostini; Phebe H van Langevelde; Maxime A Siegler; Dennis G H Hetterscheid

doi:10.1021/acscatal.7b03284

Catalytic Activity of an Iron-Based Water Oxidation Catalyst: Substrate Effects of Graphitic Electrodes

ACS Catal. 2018 Feb 2;8(2):1052-1061. doi: 10.1021/acscatal.7b03284. Epub 2017 Dec 21.

Authors

Konstantin G Kottrup¹, Silvia D'Agostini¹, Phebe H van Langevelde¹, Maxime A Siegler², Dennis G H Hetterscheid¹

Affiliations

¹ Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands.
² Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States.

Abstract

The synthesis, characterization, and electrochemical studies of the dinuclear complex [(MeOH)Fe(Hbbpya)-μ-O-(Hbbpya)Fe(MeOH)](OTf)₄ (1) (with Hbbpya = N,N-bis(2,2'-bipyrid-6-yl)amine) are described. With the help of online electrochemical mass spectrometry, the complex is demonstrated to be active as a water oxidation catalyst. Comparing the results obtained for different electrode materials shows a clear substrate influence of the electrode, as the complex shows a significantly lower catalytic overpotential on graphitic working electrodes in comparison to other electrode materials. Cyclic voltammetry experiments provide evidence that the structure of complex 1 undergoes reversible changes under high-potential conditions, regenerating the original structure of complex 1 upon returning to lower potentials. Results from electrochemical quartz crystal microbalance experiments rule out that catalysis proceeds via deposition of catalytically active material on the electrode surface.