ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Understanding the direct methane conversion to oxygenates on graphene-supported single 3d metal atom catalysts

Leila Bahri, Faten Mbarki, and Karim Harrath

Department of Chemistry, College of Sciences, University of Hafar Al-Batin, Hafar Al-Batin, Kingdom of Saudi Arabia

E-mail: karimharath2011@hotmail.fr

Received: 11 May 2022  Accepted: 24 November 2022

Abstract:

Direct methane conversion to value-added oxygenate products is an important approach for the effective utilization of CH₄. However, selective C─H bond activation of CH₄ remains challenging. Herein, we investigated the methane-to-methanol conversion mechanism on MN₄-embedded graphene (M = V, Mn, Cr, Fe, Co, Ni, and Cu) via density functional theory computations. We found that the Cu@N₄graphene and Ni@N₄graphene catalysts showed an outstanding C─H bond activation with low barrier energy of 0.45 and 0.28 eV, respectively. In addition, a detailed investigation of the electronic proprieties of the metal site, the CH₃ intermediate adsorption energy and C─H bond cleavage barrier energy demonstrates that the d-band center of metal can be a descriptor for C─H bond cleavage activity and reveal a thermodynamic-kinetic relationship: thus, the high affinity to CH₃ intermediate led to facile activation of C─H bond. Overall, this work provides a better understanding of graphene-supported single metal atom activity and selectivity toward methane oxidation, facilitating the design and fabrication of new 2D materials supported by single-atom catalysts for selective methane conversion.

Graphic Abstract

Keywords: Methane conversion; Single atom catalyst; DFT calculations

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-023-02738-y

Chemical Papers 77 (7) 3759–3767 (2023)