Improvement of Electrochemical Water Oxidation by Fine-Tuning the Structure of Tetradentate N4 Ligands of Molecular Copper CatalystsShow others and affiliations
2017 (English)In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, no 22, p. 4581-4588Article in journal (Refereed) Published
Abstract [en]
Two copper complexes, [(L1)Cu(OH2)](BF4)2 [1; L1=N,N′-dimethyl-N,N′-bis(pyridin-2-ylmethyl)-1,2-diaminoethane] and [(L2)Cu(OH2)](BF4)2 [2, L2=2,7-bis(2-pyridyl)-3,6-diaza-2,6-octadiene], were prepared as molecular water oxidation catalysts. Complex 1 displayed an overpotential (η) of 1.07 V at 1 mA cm−2 and an observed rate constant (kobs) of 13.5 s−1 at η 1.0 V in pH 9.0 phosphate buffer solution, whereas 2 exhibited a significantly smaller η (0.70 V) to reach 1 mA cm−2 and a higher kobs (50.4 s−1) than 1 under identical test conditions. Additionally, 2 displayed better stability than 1 in controlled potential electrolysis experiments with a faradaic efficiency of 94 % for O2 evolution at 1.58 V, when a casing tube was used for the Pt cathode. A possible mechanism for 1- and 2-catalyzed O2 evolution reactions is discussed based on the experimental evidence. These comparative results indicate that fine-tuning the structures of tetradentate N4 ligands can bring about significant change in the performance of copper complexes for electrochemical water oxidation.
Place, publisher, year, edition, pages
Wiley-VCH Verlagsgesellschaft, 2017. Vol. 10, no 22, p. 4581-4588
Keywords [en]
copper, electrocatalysis, homogeneous catalysis, N ligands, water oxidation, Catalysis, Catalysts, Ligands, Oxidation, Rate constants, Controlled potential electrolysis, Experimental evidence, Faradaic efficiencies, Phosphate buffer solutions, Possible mechanisms, Tuning, coordination compound, ligand, oxygen, water, chemical structure, chemistry, electrochemical analysis, electrolysis, oxidation reduction reaction, procedures, Coordination Complexes, Electrochemical Techniques, Molecular Structure, Oxidation-Reduction
National Category
Other Chemistry Topics
Identifiers
URN: urn:nbn:se:kth:diva-227141DOI: 10.1002/cssc.201701458ISI: 000416158500035PubMedID: 28868648Scopus ID: 2-s2.0-85035058311OAI: oai:DiVA.org:kth-227141DiVA, id: diva2:1202992
Funder
Swedish Energy AgencySwedish Research CouncilKnut and Alice Wallenberg Foundation
Note
QC 20180502
2018-05-022018-05-022019-02-07Bibliographically approved