Role of ferrocene-derived iron species in the catalytic graphitization of novolak resins
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Role of ferrocene-derived iron species in the catalytic graphitization of novolak resins Carmen Greice Renda1,* , Cynthia Paola Contreras Medrano4, Leonardo Jose Dalla Costa1, Fred Jochen Litterst4,5, Elisa Maria Baggio Saitovitch4, Claudio Jose´ Magon3, Alexandre Jose´ Gualdi1, Tiago Venaˆncio1, Roberto Bertholdo2, Ailton Jose´ Moreira1, Gian Paulo Giovanni Freschi2, and Alessandra de Almeida Lucas1 1
Federal University of São Carlos, Washington Luiz Highway, km 235, São Carlos, SP 13565-905, Brazil Institute of Science and Technology, Federal University of Alfenas, José A. Vilela Highway, 11999, BR 267, Km 533, Poços de Caldas, MG 37715-400, Brazil 3 University of São Paulo, Institute of Physics of São Carlos, Trabalhador São Carlense Highway, 400, Parque Arnold Schimidt, São Carlos, SP 13566-590, Brazil 4 Brazilian Center of Research in Physics – CBPF/MCTI, Dr. Xavier Sigaud Street, 150, Urca, Rio de Janeiro, RJ 22290-180, Brazil 5 Institut für Physik Der Kondensierten Materie, Technische Universität Braunschweig, 38106 Braunschweig, Germany 2
Received: 17 April 2020
ABSTRACT
Accepted: 8 September 2020
Catalytic graphitization has been used since years, normally by heating from room temperature to 2227 or 3027 °C. Ferrocene was used to induce the graphitization in modified novolak phenolic resins synthesized in laboratory (PR). In this study, the intermediate carbon structures containing iron during the graphitization process, obtained after the different steps of heat treatment from 200 to 1000 °C, were identified concerning the oxidation states of iron and morphological and structural variations. The role of iron in these intermediate structures has not been fully evaluated yet by resonance and spectroscopy techniques; therefore, in this study, it will be discussed briefly. The following techniques were employed: X-ray powder diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM), standard solid-state 13carbon nuclear magnetic resonance (solid-state 13C-NMR), 57Fe-Mo¨ssbauer and electron paramagnetic resonance (EPR) spectroscopies. In the material (PRFc) obtained by heat treatment for 5 h at 1000 °C, there were identified Fe2O3 nanocrystals, as well as Fe2O3, Fe3C and c-iron present inside and outside of an onion-like hollow carbon structure. This structure of PRFc treated at 1000 °C has shown high efficiency in removing the pesticide atrazine (ATZ) in an aqueous medium and influenced the degradation mechanism of ATZ and the formation of atrazine-2-hydroxy (HAT).
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Springer Science+Business
Media, LLC, part of Springer Nature 2020
Handling Editor: Dale Huber.
Address correspondence to E-mail: [email protected]; [email protected]
https://doi.org/10.1007/s10853-020-05312-z
J Mater Sci
GRAPHICAL ABSTRACT
Introduction There has been a growing demand for investigations related to carbon allotropes, such as graphite [1], carbon nanotubes [2], graphene [3, 4] and graphenebased [5], due to their various thermal, optical, chemical, charge transportation, mechanical
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