Title: Cyclohexane Oxidative Dehydrogenation on Graphene-Oxide-Supported Cobalt Ferrite Nanohybrids: Effect of Dynamic Nature of Active Sites on Reaction Selectivity
Authors: S. A. Kadam, S. Sandoval, Z. Bastl, K. Simkovičová, L. Kvítek, J. Jašík, J. E. Olszówka, S. Valtera, M. Vaidulych, J. Morávková, P. Sazama, D. Kubička, A. Travert, J. A. van Bokhoven, A. Fortunelli, A. Kleibert, M. Kalbáč, S. Vajda
DOI: https://doi.org/10.1021/acscatal.3c02592
Date: 10/05/2023
Working Group: WG3
Grant Period: 1st GP 2022-2023
Grant Period Goal (number): GPG2, GOG4
Covered deliverables from the MoU (number): 1.1.1
Countries involved: Czeckia, Italy, France, Switzerland
Number of female/young/ITC coauthors: 4/8/13
Abstract: In this work, we investigated cyclohexane oxidative dehydrogenation (ODH) catalyzed by cobalt ferrite nanoparticles supported on reduced graphene oxide (RGO). We aim to identify the active sites that are specifically responsible for full and partial dehydrogenation using advanced spectroscopic techniques such as X-ray photoelectron emission microscopy (XPEEM) and X-ray photoelectron spectroscopy (XPS) along with kinetic analysis. Spectroscopically, we propose that Fe3+/Td sites could exclusively produce benzene through full cyclohexane dehydrogenation, while kinetic analysis shows that oxygen-derived species (O*) are responsible for partial dehydrogenation to form cyclohexene in a single catalytic sojourn. We unravel the dynamic cooperativity between octahedral and tetrahedral sites and the unique role of the support in masking undesired active (Fe3+/Td) sites. This phenomenon was strategically used to control the abundance of these species on the catalyst surface by varying the particle size and the wt % content of the nanoparticles on the RGO support in order to control the reaction selectivity without compromising reaction rates which are otherwise extremely challenging due to the much favorable thermodynamics for complete dehydrogenation and complete combustion under oxidative conditions.
