Autor según el artículo: López, J. ; Musaev, D. ; Craig, H. ; Galán-Mascarós, J. R. ; Carbó, J. ; Poblet, J. M:

Departamento: Química Física i Inorgànica

Autor/es de la URV: LÓPEZ FERNÁNDEZ, JAVIER; Musaev, D. ; Craig, H. ; Galán-Mascarós, J. R. ; CARBÓ MARTIN, JORGE JUAN; POBLET RIUS, JOSEP MARIA

Palabras clave: polyoxometalates water oxidation catalysis DFT

Resumen: A mechanism of water oxidation catalyzed by the carbon-free tetra-Co containing polyoxometalates [Co4(H2O)2(PW9O34)2]10− (PCo4) and [Co4(H2O)2(VW9O34)2]10− (VCo4) is elucidated by DFT calculations. Computational analysis for PCo4 suggests that a first PCET step may proceed via a sequential electron-then-proton transfer (ET + PT) pathway and leads to one electron oxidize species S1 (POM-CoIIIOH). In contrast, the second PCET, which controls the potential required to form POM-CoIII active species S2 is clearly a concerted process. The overall S0 → S2 transformation is estimated to require less than 1.48 V and 1.62 V applied potential at pH = 8 for PCo4 and VCo4 anions, respectively. At operando conditions, with the presence of a buffer and with an applied potential above the threshold potential the two H-atom removal could take place via concerted pathways. These steps represent rapid pre-equilibria before the rate determining step, which corresponds to the OO bond formation. The key chemical step occurs via nucleophilic attack of an external water molecule to intermediate S2. We assume that this step governs the kinetics of the reaction. Comparison of the calculated energetics and electronic structures of intermediate species in the PCo4 and VCo4 catalyzed water oxidation cycle shows that coupling of d orbitals of V and Co atoms in VCo4 increases the oxidation potential of the Co-center. The orbital coupling is also responsible for the higher catalytic activity of VCo4 because it increases the electrophilicity of CoIII moiety in the key S2 species.

Grupo de investigación: Química Quàntica

Áreas temáticas: Química Química Chemistry

Acceso a la licencia de uso: https://creativecommons.org/licenses/by/3.0/es/

ISSN: 0021-9517

Identificador del autor: 0000-0003-0322-6796; ; ; ; 0000-0002-3945-6721; 0000-0002-4533-0623

Fecha de alta del registro: 2018-03-05

Página final: 63

Volumen de revista: 350

Versión del articulo depositado: info:eu-repo/semantics/publishedVersion

Enlace a la fuente original: https://www.sciencedirect.com/science/article/pii/S0021951717301021?via%3Dihub

Programa de financiación: plan; Excelencia; CTQ2014-52774-P altres; Grupos Consolidados; 2014SGR199 altres; ICREA Academia

DOI del artículo: 10.1016/j.jcat.2017.03.018

Entidad: Universitat Rovira i Virgili

Año de publicación de la revista: 2017

Página inicial: 56

Tipo de publicación: Article Artículo Article