doi:10.1016/j.carbon.2014.11.016engBlanco, MatíasÁlvarez, PatriciaBlanco, ClaraJiménez, M. VictoriaFernández-Tornos, JavierPérez-Torrente, Jesús J.Oro, Luis A.Menéndez, RosaGraphene-NHC-iridium hybrid catalysts built through -OH covalent linkage Dedicated to the lasting Memory of Prof. Dr. María Pilar García for her valuable talent as human, teacher and chemistART-2015-94136Graphene oxide (GO) and thermally reduced graphene oxide (TRGO) were covalently modified with imidazolium salts through their hydroxyl surface groups. The selective reaction of the -OH groups with p-nitrophenylchloroformate produced labile intermediate organic carbonate functions which were used for the covalent anchoring of a hydroxy-functionalized imidazolium salt. Nanohybrid materials containing iridium N-heterocyclic carbene (NHC)-type organometallic complexes were prepared by causing the imidazolium-functionalized materials to react with Ir(µ-OMe)(cod)]2. The iridium content of the graphene-based hybrid catalysts, as determined by XPS and ICP-MS was the order of ~5 and 10 wt.%, for the TRGO and GO-based materials, respectively. The graphene-supported iridium hybrid materials were active in the heterogeneous hydrogen-transfer reduction of cyclohexanone to cyclohexanol with 2-propanol/KOH as the hydrogen source. The thermally reduced graphene-NHC-iridium hybrid catalyst showed the best catalytic performance with an initial TOF of 11.500 h-1, slightly better than the related acetoxy-functionalized NHC iridium homogeneous catalyst. A good catalyst recyclability and stability were achieved.2015http://zaguan.unizar.es/record/12787410.1016/j.carbon.2014.11.016http://zaguan.unizar.es/record/127874oai:zaguan.unizar.es:127874info:eu-repo/grantAgreement/ES/MINECO/CSD2009-00050info:eu-repo/grantAgreement/ES/MINECO/CTQ2013-42532-PCarbon 83 (2015), 21-31by-nc-ndhttps://creativecommons.org/licenses/by-nc-nd/4.0/deed.esinfo:eu-repo/semantics/openAccess