Issue 44, 2020

Role of defects in carbon materials during metal-free formic acid dehydrogenation

Abstract

Commercial graphite (GP), graphite oxide (GO), and two carbon nanofibers (CNF-PR24-PS and CNF-PR24-LHT) were used as catalysts for the metal-free dehydrogenation reaction of formic acid (FA) in the liquid phase. Raman and XPS spectroscopy demonstrated that the activity is directly correlated with the defectiveness of the carbon material (GO > CNF-PR24-PS > CNF-PR24-LHT > GP). Strong deactivation phenomena were observed for all the catalysts after 5 minutes of reaction. Density functional theory (DFT) calculations demonstrated that the single vacancies present on the graphitic layers are the only active sites for FA dehydrogenation, while other defects, such as double vacancies and Stone–Wales (SW) defects, rarely adsorb FA molecules. Two different reaction pathways were found, one passing through a carboxyl species and the other through a hydroxymethylene intermediate. In both mechanisms, the active sites were poisoned by an intermediate species such as CO and atomic hydrogen, explaining the catalyst deactivation observed in the experimental results.

Graphical abstract: Role of defects in carbon materials during metal-free formic acid dehydrogenation

Supplementary files

Article information

Article type
Paper
Submitted
05 Aug 2020
Accepted
13 Oct 2020
First published
14 Oct 2020

Nanoscale, 2020,12, 22768-22777

Role of defects in carbon materials during metal-free formic acid dehydrogenation

I. Barlocco, S. Capelli, X. Lu, S. Tumiati, N. Dimitratos, A. Roldan and A. Villa, Nanoscale, 2020, 12, 22768 DOI: 10.1039/D0NR05774F

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements