Metal phthalocyanines and imidazolium bromide Copolymers supported on multi-walled carbon nanotubes: : a "lego-like" assembly of hybrid bifunctional materials applied for CO2 conversion

Benedetto Taormina, Remy Jouclas, Alwyn DSOUZA, Anthony Morena, Michelangelo Gruttadauria, Carmela Aprile, Francesco Giacalone

Résultats de recherche: Contribution à un journal/une revue › Article › Revue par des pairs

2 Téléchargements (Pure)

Résumé

The present study explores the development of hybrid heterogeneous bifunctional catalysts supported on multi-walled carbon nanotubes (MWCNT) for CO2 valorization in the synthesis of cyclic carbonates. These materials integrate both nucleophilic species (imidazolium bromide) and Lewis acid species (magnesium, copper, and zinc phthalocyanines), revealing improved catalytic activity through synergistic effects. MWCNT are employed as support enhancing the accessibility of active sites and the overall catalytic performance. Three different metal-phthalocyanines with imidazole moieties (MgPC-Im4, CuPC-Im4 and ZnPC-Im4) were covalently anchored onto MWCNT through an atom economic polymerization process, resulting in new bifunctional materials (MPC@MWCNT) in which the polymeric network fully covers the nanotubes longitudinally. Comprehensive characterization of the hybrids by using different techniques confirmed the successful synthesis of these materials. Catalytic testing of the MPC@MWCNT materials in epoxide-CO2 cycloaddition reactions revealed that the MgPC@MWCNT hybrid exhibited superior catalytic activity compared to its unsupported counterpart, highlighting the benefits of the MWCNT as support (TON = 8050 vs TON = 7120), reaching very high TON values (up to 19920) at very low catalytic loadings (0.004–0.0013 mol% based on metal content). Importantly, this study introduces a simple yet effective novel method for covalently attaching high amounts of metal-phthalocyanines onto MWCNT. Potentially, the "lego-like" approach of this method allows for the creation of diverse materials with different metal centres, enabling access to a number of different applications in the field of Materials Science.
langue originaleAnglais
Numéro d'article120508
journalCarbon
Volume243
Les DOIs
Etat de la publicationPublié - juin 2025

Financement

This research was funded by University of Palermo and the Italian Ministry of Education (PRIN 2017 project no. 2017W8KNZW). This research is supported by the F.R.S-FNRS via funding grants GEQ U. G014.19 EQP U.N034.17 and PDR T.0004.21 , European Regional Development Fund (FEDER) and the Walloon Region (Low Carbon Footprint Materials \u2013 BIORG-EL project . B. T. gratefully acknowledges the University of Palermo and University of Namur for a co-funded PhD fellowship. The authors acknowledge Dr. Luca Fusaro and Dr. Alberto Spinella for their support to the NMR experiments. This research used resources of PC2 (Plateforme Technologique Physico-Chemical Characterization), MORPH-IM (Morphology & Imaging) and SIAM (Synthesis, Irradiation & Analysis of Materials) technology platforms located at the University of Namur. The FT-IR spectra acquired for the three MPC@MWCNT (Fig. S4) exhibit the same types of bands previously observed for their precursors thus confirming the presence of both imidazolium and phthalocyanine moieties: specifically, despite the samples have been dried at 60 \u00B0C for 3h before the analysis, the bands at 3400 cm\u22121 corresponding to the vibrational stretching of O\u2013H bonds from water molecules is still visible as a consequence of the adsorbed H2O onto the very hygroscopic imidazolium fractions; the bands between 2700 and 3100 cm\u22121 correspond to the stretching of C\u2013H bonds, and finally, the bands between 1450 and 1620 cm\u22121 are due to the vibrational stretching of C[dbnd]C and C[dbnd]N bonds present in the aromatic core of the phthalocyanines. Lastly, there are also some bands in the range of 1000 and 1200 cm\u22121 which are consistent with the bending vibration modes of both aliphatic and aromatic C\u2013H bonds (Fig. S4). The morphology of these materials was investigated using Transmission Electron Microscopy (TEM): TEM micrographs obtained for all three MPC@MWCNT solids (Fig. 2) show clearly that in all the cases the co-polymerization process occurred uniformly across the surface of the MWCNT, so to have the MPC-(Imi-Styryl)4Br4/Bis-Vinyl-Imi-Br co-polymer following the scaffold of the nanotubes. In combination with this outcome, EDX micrographs (Fig. S5\u2013S7) of the three materials show that there is not segregation of phase, thus suggesting an uniform distribution of their elemental components (and therefore of their active sites) all over the shape of the nanotubes.The specific surface area (SSA) of each MPC@MWCNT has been calculated exploiting the Brauner- Emmett- Teller (BET) equation [38], and resulted in 80 m2/g, 100 m2/g and 80 m2/g for MgPC@MWCNT, CuPC@MWCNT and ZnPC@MWCNT, respectively. The three materials supported onto MWCNT show a higher SSA than the one related to the analogous unsupported material MgPC\u2013SIBI\u2013Br (40 m2/g) [23]. This result can be ascribed to the presence of the MWCNT (SSA of 240 m2/g) which served as an effective templating scaffold for the co-polymerization process. Their large specific surface area provided an extensive interface for co-polymer growth, favouring the integration of the co-polymer onto the nanostructure.This research was funded by University of Palermo and the Italian Ministry of Education (PRIN 2017 project no. 2017W8KNZW). This research is supported by the F.R.S-FNRS via funding grants GEQ U. G014.19 EQP U.N034.17 and PDR T.0004.21, European Regional Development Fund (FEDER) and the Walloon Region (Low Carbon Footprint Materials \u2013 BIORG-EL project. B. T. gratefully acknowledges the University of Palermo and University of Namur for a co-funded PhD fellowship. The authors acknowledge Dr. Luca Fusaro and Dr. Alberto Spinella for their support to the NMR experiments. This research used resources of PC2 (Plateforme Technologique Physico-Chemical Characterization), MORPH-IM (Morphology & Imaging) and SIAM (Synthesis, Irradiation & Analysis of Materials) technology platforms located at the University of Namur.

Bailleurs de fondsNuméro du bailleur de fonds
Low Carbon Footprint Materials
Università degli Studi di Palermo
Région Walonne
MWCNT
MORPH-IM
European Regional Development Fund
Ministero dell’Istruzione, dell’Università e della Ricerca2017W8KNZW
Fonds De La Recherche Scientifique - FNRSGEQ U. G014.19 EQP U.N034.17, PDR T.0004.21

    Accès au document

    Autres fichiers et liens

      Empreinte digitale

      Examiner les sujets de recherche de « Metal phthalocyanines and imidazolium bromide Copolymers supported on multi-walled carbon nanotubes: : a "lego-like" assembly of hybrid bifunctional materials applied for CO2 conversion ». Ensemble, ils forment une empreinte digitale unique.
      Afficher l'empreinte digitale dans sa totalité

      Contient cette citation