Control over Electrochemical Water Oxidation Catalysis by Preorganization of Molecular Ruthenium Catalysts in Self‐Assembled Nanospheres. Issue 35 (1st August 2018)

• Record Type: Journal Article
• Authors: Yu, Fengshou; Poole, David; Mathew, Simon; Yan, Ning; Hessels, Joeri; Orth, Nicole; Ivanović‐Burmazović, Ivana; Reek, Joost N. H.
• Is Part Of: Angewandte Chemie international edition. Volume 57:Issue 35(2018)
• Page Start: 11247
• Page End: 11251
• Publication Date: 2018-08-01
• Subjects: electrochemical catalysis -- ruthenium complexes -- supramolecular chemistry -- water oxidation; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201805244
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: Oxygen formation through water oxidation catalysis is a key reaction in the context of fuel generation from renewable energies. The number of homogeneous catalysts that catalyze water oxidation at high rate with low overpotential is limited. Ruthenium complexes can be particularly active, especially if they facilitate a dinuclear pathway for oxygen bond formation step. A supramolecular encapsulation strategy is reported that involves preorganization of dilute solutions (10 −5 m ) of ruthenium complexes to yield high local catalyst concentrations (up to 0.54 m ). The preorganization strategy enhances the water oxidation rate by two‐orders of magnitude to 125 s −1, as it facilitates the diffusion‐controlled rate‐limiting dinuclear coupling step. Moreover, it modulates reaction rates, enabling comprehensive elucidation of electrocatalytic reaction mechanisms. Abstract : The water oxidation rate is enhanced by two orders of magnitude by preorganising Ru(bda)(PySO3 TBA)2 catalysts to nanospheres, effectively eliminating diffusion limitations for the O−O coupling step at very low overall catalyst concentration. This preorganization strategy also provides new ways to study the reaction mechanism by varying the local catalyst concentration, while leaving the overall concentrations the same.