Effect of the thermal treatment of Fe/N/C catalysts for the oxygen reduction reaction synthesized by pyrolysis of covalent organic frameworks

DOI: 10.1021/acs.iecr.1c02841

Authors: Álvaro García (Instituto de Catálisis y Petroleoquímica, CSIC) , Tarrick Haynes (Instituto de Catálisis y Petroleoquímica, CSIC) , Maria Retuerto (Instituto de Catálisis y Petroleoquímica, CSIC) , Pilar Ferrer (Diamond Light Source) , Laura Pascual (Instituto de Catálisis y Petroleoquímica, CSIC) , Miguel A. Peña (nstituto de Catálisis y Petroleoquímica, CSIC) , Mohamed Abdel Salam (King Abdulaziz University) , Mohamed Mokhtar (King Abdulaziz University) , Diego Gianolio (Diamond Light Source) , Sergio Rojas (Instituto de Catálisis y Petroleoquímica, CSIC)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Industrial & Engineering Chemistry Research

State: Published (Approved)
Published: November 2021
Diamond Proposal Number(s): 24881

Abstract: A nitrogen-containing covalent organic framework obtained from the polymerization of 1,3-dicyanobenzene has been used as a starting material for the synthesis of Fe/N/C catalysts for the oxygen reduction reaction (ORR). In this work we report the effect of the thermal treatments on the nature and catalytic properties of the catalysts obtained after the thermal treatments. After the first thermal treatment, the catalysts obtained contain metallic iron and iron carbide particles, along with a minority fraction of inorganic FeNx sites. After acid leaching and a second thermal treatment, FeNx sites remain in the catalysts, along with a minor fraction of graphite-wrapped Fe3C particles. Both catalysts display high activity for the ORR, with the catalyst subjected to acid leaching and a second thermal treatment, 2HT-1,3DCB, displaying higher ORR activity and a lower production of H2O2. This observation suggests that iron particles, such as Fe3C, display ORR activity but mainly toward the two-electron pathway. On the contrary, FeNx ensembles promote the ORR via the four-electron pathway, that is, via H2O formation.

Journal Keywords: Redox reactions; Iron; Carbon; Catalysts; Leaching

Diamond Keywords: Fuel Cells

Subject Areas: Chemistry, Energy


Instruments: B18-Core EXAFS

Added On: 08/11/2021 08:32

Documents:
acs.iecr.1c02841.pdf

Discipline Tags:

Energy Storage Energy Physical Chemistry Catalysis Chemistry Organometallic Chemistry

Technical Tags:

Spectroscopy X-ray Absorption Spectroscopy (XAS)