Autor segons l'article: Azmani, Khalid; Besora, Maria; Soriano-Lopez, Joaquin; Landolsi, Meriem; Teillout, Anne-Lucie; de Oliveira, Pedro; Mbomekalle, Israel-Martyr; Poblet, Josep M.; Galan-Mascaros, Jose-Ramon;
Departament: Química Física i Inorgànica
Autor/s de la URV: Azmani, Khalid / Besora Bonet, Maria / Poblet Rius, Josep Maria
Paraules clau: Water oxidation catalysts Structure-reactivity relationships Solid-state electrodes Proton coupled electron transfers Polyoxometalates Phosphate Oxygen-evolution Oxygen evolution reaction (oer) Oxidation Molecular-orbital methods Iron compounds Hydrogen Homogeneous catalyst Exchange Energy Electronic differences Electron transport properties Electrocatalysts Computational calculations Computational analysis Cobalt Catalysts Activation energy Abundant transition-metal Ab-initio
Resum: Cobalt polyoxometalates (Co-POMs) have emerged as promising water oxidation catalysts (WOCs), with the added advantage of their molecular nature despite being metal oxide fragments. In comparison with metal oxides, that do not offer well-defined active surfaces, POMs have a controlled, discrete structure that allows for precise correlations between experiment and computational analyses. Thus, beyond highly active WOCs, POMs are also model systems to gain deeper mechanistic understanding on the oxygen evolution reaction (OER). The tetracobalt Weakley sandwich [Co-4(II)(H2O)(2)(B-alpha-PW9O34)(2)](10-) (Co-4-WS) has been one of the most extensively studied. We have compared its activity with that of the iron analog [Fe-4(III)(H2O)(2)(B-alpha-PW9O34)(2)](6-) (Fe-4-WS) looking for the electronic effects determining their activity. Furthermore, the effect of POM nuclearity was also investigated by comparison with the iron- and cobalt-monosubstituted Keggin clusters. Electrocatalytic experiments employing solid state electrodes containing the POMs and the corresponding computational calculations demonstrate that Co-II-POMs display better WOC activity than the Fe-III derivatives. Moreover, the activity of POMs is less influenced by their nuclearity, thus Weakley sandwich moieties show slightly improved WOC characteristics than Keggin clusters. In good agreement with the experimental data, computational methods, including pK(a) values, confirm that the resting state for Fe-POMs in neutral media corresponds to the S-1 (Fe-III-OH) species. Overall, the proposed reaction mechanism for Fe-4-WS is analogous to that found for Co-4-WS, despite their electronic differences. The potential limiting step is a proton-coupled electron transfer event yielding the active S-2 (Fe-IV=O) species, which receives a water nucleophilic attack to form the O-O bond. The latter has activation energies slightly higher than those computed for the Co-POMs, in good agreement with experimental observations. These results provide new insights for the accurate understanding of the structure-reactivity relationships of polyoxometalates in particular, and or metal oxides in general, which are of utmost importance for the development of new bottom-up synthetic approaches to design efficient, robust and non-expensive earth-abundant water oxidation catalysts.
Àrees temàtiques: Química Materiais Interdisciplinar General chemistry Farmacia Ciências biológicas iii Ciências biológicas i Chemistry, multidisciplinary Chemistry (miscellaneous) Chemistry (all) Astronomia / física
Accès a la llicència d'ús: https://creativecommons.org/licenses/by/3.0/es/
Adreça de correu electrònic de l'autor: maria.besora@urv.cat josepmaria.poblet@urv.cat
Identificador de l'autor: 0000-0002-6656-5827 0000-0002-4533-0623
Data d'alta del registre: 2024-07-27
Volum de revista: 12
Versió de l'article dipositat: info:eu-repo/semantics/publishedVersion
URL Document de llicència: https://repositori.urv.cat/ca/proteccio-de-dades/
Referència a l'article segons font original: Chemical Science. 12 (25): 8755-8766
Referència de l'ítem segons les normes APA: Azmani, Khalid; Besora, Maria; Soriano-Lopez, Joaquin; Landolsi, Meriem; Teillout, Anne-Lucie; de Oliveira, Pedro; Mbomekalle, Israel-Martyr; Poblet, (2021). Understanding polyoxometalates as water oxidation catalysts through iron vs. cobalt reactivity. Chemical Science, 12(25), 8755-8766. DOI: 10.1039/d1sc01016f
Entitat: Universitat Rovira i Virgili
Any de publicació de la revista: 2021
Tipus de publicació: Journal Publications
Repositori URV