127876 20231023120953.0 doi 10.1021/acsaem.9b00137 sideral 112692 ART-2019-112692 eng Nieto, J. Enhanced Chemical and Electrochemical Water Oxidation Catalytic Activity by Hybrid Carbon Nanotube-Based Iridium Catalysts Having Sulfonate-Functionalized NHC ligands 2019 The hybrid materials resulting from the covalent attachment of iridium NHC complexes, bearing 3-methyl-imidazol-2-ylidene and 3-(propyl-3-sulfonate)-imidazol-2-ylidene ligands to carbon nanotubes through ester functions, efficiently catalyzed water oxidation under chemical and electrochemical conditions. The hybrid catalyst featuring an NHC ligand with a propyl-sulfonate wingtip has shown an improved catalytic performance compared to that of the unfunctionalized material with TOF50 numbers up to 1140 h(-1) using ammonium cerium(IV) nitrate (CAN) as electron acceptor at [CAN]/[Ir] ratios higher than 2000. The positive effect of the presence of a polar sulfonate group in water oxidation has been also observed in related molecular catalysts with compound [Ir(cod){MeIm(CH2)(3)SO3}] being more active than [IrCl(cod){MeIm(CH2)(3)OH}]. The hybrid catalysts were less active than the molecular catalysts although their productivity has been improved by allowing successive additions of CAN or at least three recycling experiments. The electrochemical water oxidation by CNT-based hybrid materials resulted much more efficient. The positive influence of a watersoluble sulfonate wingtip in the hybrid catalysts has been also identified allowing with TOF values close to 22 000 h(-1) at 1.4 V. The local structure around iridium atoms in the heterogeneous catalysts has been determined by means of EXAFS applied before and after water oxidation reactions. The first coordination shell is similar in both fresh and postcatalytic catalysts but a slightly increase in the oxidation state of iridium atoms is observed what can be correlated to the peaks shifts in the XPS spectra for the oxidized materials. Access copy available to the general public Unrestricted info:eu-repo/grantAgreement/ES/DGA-FSE/E42-17R info:eu-repo/grantAgreement/ES/MINECO-FEDER/CTQ2013-42532-P info:eu-repo/grantAgreement/ES/MINECO-FEDER/CTQ2016-75884-P info:eu-repo/semantics/openAccess by-nc-nd http://creativecommons.org/licenses/by-nc-nd/3.0/es/ 4.473 2019 CHEMISTRY, PHYSICAL 55 / 159 = 0.346 2019 Q2 T2 MATERIALS SCIENCE, MULTIDISCIPLINARY 85 / 314 = 0.271 2019 Q2 T1 ENERGY & FUELS 39 / 112 = 0.348 2019 Q2 T2 1.495 2019 Chemical Engineering (miscellaneous) 2019 Q1 Electrical and Electronic Engineering 2019 Q1 Materials Chemistry 2019 Q1 Energy Engineering and Power Technology 2019 Q1 Electrochemistry 2019 Q1 info:eu-repo/semantics/article info:eu-repo/semantics/acceptedVersion Jimenez, M.V. Universidad de Zaragoza (orcid)0000-0002-0545-9107 Alvarez, P. Perez-Mas, A.M. Gonzalez, Z. Pereira, R. Sanchez-Page, B. (orcid)0000-0001-6675-7450 Perez-Torrente, J.J. Universidad de Zaragoza (orcid)0000-0002-3327-0918 Blasco, J. Subias, G. Universidad de Zaragoza (orcid)0000-0002-9029-1977 Blanco, M. Menendez, R. 2010 760 Universidad de Zaragoza Dpto. Química Inorgánica Área Química Inorgánica 2003 395 Universidad de Zaragoza Dpto. Física Materia Condensa. Área Física Materia Condensada 2, 5 (2019), 3283-3296 ACS app. energy mater. ACS applied energy materials 2574-0962 1559161 http://zaguan.unizar.es/record/127876/files/texto_completo.pdf Postprint 946281 http://zaguan.unizar.es/record/127876/files/texto_completo.jpg?subformat=icon icon Postprint oai:zaguan.unizar.es:127876 articulos driver 2023-10-23-11:02:58 ARTICLE