Atomic level transition of graphene layer to carbon nanotubes over cobalt during ethanol decomposition reaction

• Published in: International journal of hydrogen energy Vol. 75; pp. 121 - 131
• Main Authors: Ashok, Anchu, Kumar, Anand
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 19-07-2024
• Subjects: Carbon nanofiber; Ethanol decomposition; Graphene layers; Hydrogen production; Carbon nanofiber; Graphene layers; Ethanol decomposition; Hydrogen production
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2024.01.070

Herein we report the catalytic ethanol decomposition over cobalt catalyst synthesized using conventional solution combustion synthesis (SCS). The reaction pathway proposed in-situ DRIFT analysis shows that the decomposition reaction proceeds through the formation of surface ethoxy intermediates that transformed into acetates and aldehydes which further decompose to releases CH4, H2 and CO2 with some deposition of carbon on the catalyst surface. The catalytic reaction shows 100 % ethanol conversion at 420 °C, with high selectivity of H2 in the output. The structural transformation of the catalyst and deposited carbon was analyzed using high-resolution transmission electron microscope (HRTEM). Presence of small Co nanoparticles (size <30 nm) surrounded with graphene and larger metal nanoparticles trapped inside MWCNTs was visible during a stability run over 50 h that motivates in proposing the reaction mechanism of the fluctuating metal nanoparticle along with carbon on the catalyst surface. Moreover, this work opens up the possibility of synthesizing highly dispersed Co nanoparticles in an efficient way without any complex experimental procedures and equipment that can further be used as effective catalysts in many industrial reactions.
•Catalytic reaction shows 100 % ethanol conversion at 420 °C on cobalt catalyst.•Transformation on particle and carbon structure during stability run is seen.•Co nanoparticles between 10 and 30 nm with graphene layer were observed.•Metal nanoparticles trapped inside MWCNTs after 50 h of ethanol conversion.•Proposed mechanism describes the metal nanoparticle fluctuation with carbon structure.