Open AccessNoncovalent Immobilization of Pentamethylcyclopentadienyl Iridium Complexes on Ordered Mesoporous Carbon for Electrocatalytic Water Oxidation
Author(s) -
Geer Ana M.,
Liu Chang,
Musgrave Charles B.,
Webber Christopher,
Johnson Grayson,
Zhou Hua,
Sun Cheng-Jun,
Dickie Diane A.,
Goddard William A.,
Zhang Sen,
Gunnoe T. Brent
Publication year - 2021
Publication title -
small science
Language(s) - English
Resource type - Journals
ISSN - 2688-4046
DOI - 10.1002/smsc.202100037
Subject(s) - iridium , overpotential , catalysis , chemistry , electrochemistry , mesoporous material , inorganic chemistry , non covalent interactions , stacking , infrared spectroscopy , cyclopentadienyl complex , molecule , hydrogen bond , organic chemistry , electrode
The attachment of molecular catalysts to conductive supports for the preparation of solid‐state anodes is important for the development of devices for electrocatalytic water oxidation. The preparation and characterization of three molecular cyclopentadienyl iridium(III) complexes, Cp*Ir(1‐pyrenyl(2‐pyridyl)ethanolate‐κO,κN)Cl ( 1 ) (Cp* = pentamethylcyclopentadienyl), Cp*Ir(diphenyl(2‐pyridyl)methanolate‐κO,κN)Cl ( 2 ), and [Cp*Ir(4‐(1‐pyrenyl)‐2,2′‐bipyridine)Cl]Cl ( 3 ), as precursors for electrochemical water oxidation catalysts, are reported. These complexes contain aromatic groups that can be attached via noncovalent π‐stacking to ordered mesoporous carbon (OMC). The resulting iridium‐based OMC materials ( Ir‐1 , Ir‐2, and Ir‐3 ) were tested for electrocatalytic water oxidation leading to turnover frequencies (TOFs) of 0.9–1.6 s −1 at an overpotential of 300 mV under acidic conditions. The stability of the materials is demonstrated by electrochemical cycling and X‐ray absorption spectroscopy analysis before and after catalysis. Theoretical studies on the interactions between the molecular complexes and the OMC support provide insight onto the noncovalent binding and are in agreement with the experimental loadings.