CO2 Conversion on N-Doped Carbon Catalysts via Thermo- and Electrocatalysis: Role of C-NO x Moieties

Dorottya Hursán; Marietta Ábel; Kornélia Baán; Edvin Fako; Gergely F Samu; Huu Chuong Nguyën; Núria López; Plamen Atanassov; Zoltán Kónya; András Sápi; Csaba Janáky

doi:10.1021/acscatal.2c01589

CO₂ Conversion on N-Doped Carbon Catalysts via Thermo- and Electrocatalysis: Role of C-NO _x Moieties

ACS Catal. 2022 Aug 19;12(16):10127-10140. doi: 10.1021/acscatal.2c01589. Epub 2022 Aug 4.

Authors

Dorottya Hursán^{1

2}, Marietta Ábel^{3

2}, Kornélia Baán^{3

2}, Edvin Fako⁴, Gergely F Samu^{1

2}, Huu Chuong Nguyën⁴, Núria López⁴, Plamen Atanassov^{5

6}, Zoltán Kónya^{3

2}, András Sápi³, Csaba Janáky^{1

2}

Affiliations

¹ Department of Physical Chemistry and Materials Science, University of Szeged, H-6720 Szeged, Hungary.
² Interdisciplinary Excellence Centre, University of Szeged, H-6720 Szeged, Hungary.
³ Department of Applied and Environmental Chemistry, University of Szeged, H-6720 Szeged, Hungary.
⁴ Institute of Chemical Research of Catalonia, The Barcelona Institute of Science and Technology, 43007 Tarragona, Spain.
⁵ Department of Chemical and Biomolecular Engineering, University of California Irvine, Irvine, California 92697, United States.
⁶ National Fuel Cell Research Center, University of California Irvine, Irvine, California 92697, United States.

Abstract

N-doped carbon (N-C) materials are increasingly popular in different electrochemical and catalytic applications. Due to the structural and stoichiometric diversity of these materials, however, the role of different functional moieties is still controversial. We have synthesized a set of N-C catalysts, with identical morphologies (∼27 nm pore size). By systematically changing the precursors, we have varied the amount and chemical nature of N-functions on the catalyst surface. The CO₂ reduction (CO₂R) properties of these catalysts were tested in both electrochemical (EC) and thermal catalytic (TC) experiments (i.e., CO₂ + H₂ reaction). CO was the major CO₂R product in all cases, while CH₄ appeared as a minor product. Importantly, the CO₂R activity changed with the chemical composition, and the activity trend was similar in the EC and TC scenarios. The activity was correlated with the amount of different N-functions, and a correlation was found for the -NO _x species. Interestingly, the amount of this species decreased radically during EC CO₂R, which was coupled with the performance decrease. The observations were rationalized by the adsorption/desorption properties of the samples, while theoretical insights indicated a similarity between the EC and TC paths.