Hits:

Indexed by:期刊论文

Date of Publication:2017-11-23

Journal:CHEMSUSCHEM

Included Journals:SCIE、EI、PubMed、Scopus

Volume:10

Issue:22,SI

Page Number:4581-4588

ISSN No.:1864-5631

Key Words:copper; electrocatalysis; homogeneous catalysis; N ligands; water oxidation

Abstract: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 (eta) of 1.07V at 1 mAcm(-2) and an observed rate constant (k(obs)) of 13.5 s(-1) at eta 1.0 V in pH 9.0 phosphate buffer solution, whereas 2 exhibited a significantly smaller eta (0.70 V) to reach 1 mAcm(-2) and a higher k(obs) (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 O-2 evolution at 1.58 V, when a casing tube was used for the Pt cathode. A possible mechanism for 1- and 2-catalyzed O-2 evolution reactions is discussed based on the experimental evidence. These comparative results indicate that fine-tuning the structures of tetradentate N-4 ligands can bring about significant change in the performance of copper complexes for electrochemical water oxidation.