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

Barlocco, Ilaria, Capelli, Sofia, Lu, Xiuyuan, Tumiati, Simone, Dimitratos, Nikolaos, Roldan, Alberto and Villa, Alberto 2020. Role of defects in carbon materials during metal-free formic acid dehydrogenation. Nanoscale 12 (44) , pp. 22768-22777. 10.1039/D0NR05774F

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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.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Chemistry Cardiff Catalysis Institute (CCI) Advanced Research Computing @ Cardiff (ARCCA)
Publisher:	Royal Society of Chemistry
ISSN:	2040-3372
Date of First Compliant Deposit:	11 December 2020
Date of Acceptance:	13 October 2020
Last Modified:	04 Dec 2024 18:30
URI:	https://orca.cardiff.ac.uk/id/eprint/136951

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