131346 20240207154753.0 doi 10.1021/acscatal.1c01395 sideral 135367 ART-2021-135367 eng Geer, Ana M. (orcid)0000-0003-1115-6759 Electrocatalytic Water Oxidation by a Trinuclear Copper(II) Complex 2021 We report a trinuclear copper(II) complex, [(DAM)Cu3(μ3-O)][Cl]4 (1, DAM = dodecaaza macrotetracycle), as a homogeneous electrocatalyst for water oxidation to dioxygen in phosphate-buffered solutions at pH 7.0, 8.1, and 11.5. Electrocatalytic water oxidation at pH 7 occurs at an overpotential of 550 mV with a turnover frequency of ∼19 s–1 at 1.5 V vs NHE. Controlled potential electrolysis (CPE) experiments at pH 11.5 over 3 h at 1.2 V and at pH 8.1 for 40 min at 1.37 V vs NHE confirm the evolution of dioxygen with Faradaic efficiencies of 81% and 45%, respectively. Rinse tests conducted after CPE studies provide evidence for the homogeneous nature of the catalysis. The linear dependence of the current density on the catalyst concentration indicates a likely first-order dependence on the Cu precatalyst 1, while kinetic isotope studies (H2O versus D2O) point to involvement of a proton in or preceding the rate-determining step. Rotating ring-disk electrode measurements at pH 8.1 and 11.2 show no evidence of H2O2 formation and support selectivity to form dioxygen. Freeze-quench electron paramagnetic resonance studies during electrolysis provide evidence for the formation of a molecular copper intermediate. Experimental and computational studies support a key role of the phosphate as an acceptor base. Moreover, density functional theory calculations highlight the importance of second-sphere interactions and the role of the nitrogen-based ligands to facilitate proton transfer processes. Access copy available to the general public Unrestricted info:eu-repo/semantics/openAccess All rights reserved http://www.europeana.eu/rights/rr-f/ 13.7 2021 CHEMISTRY, PHYSICAL 19 / 165 = 0.115 2021 Q1 T1 4.202 2021 Chemistry (miscellaneous) 2021 Q1 Catalysis 2021 Q1 20.8 2021 info:eu-repo/semantics/article info:eu-repo/semantics/acceptedVersion Musgrave III, Charles Webber, Christopher Nielsen, Robert J. McKeown, Bradley A. Liu, Chang Schleker, P. Philipp M. Jakes, Peter Jia, Xiaofan Dickie, Diane A. Granwehr, Josef Zhang, Sen Machan, Charles W. Goddard, William A. Gunnoe, T. Brent 11, 12 (2021), 7223-7240 ACS catal. ACS CATALYSIS 2155-5435 1846672 http://zaguan.unizar.es/record/131346/files/texto_completo.pdf Postprint 2400696 http://zaguan.unizar.es/record/131346/files/texto_completo.jpg?subformat=icon icon Postprint oai:zaguan.unizar.es:131346 articulos driver 2024-02-07-14:41:34 ARTICLE