Volume 230, 2021

Conversion of CO2 and small alkanes to platform chemicals over Mo2C-based catalysts

Abstract

The performance of Mo2C-based catalysts in CO2 assisted oxidative dehydrogenation (CO2-ODH) of ethane was evaluated. Mo2C on SiO2 was synthesized via three different techniques: wet impregnation (WI), hybrid nanocrystal technique (HNC) and sol–gel method (SG) and exposed to the same carburization conditions. In terms of characteristic properties, the allotrope composition was the most affected, with the SG sample containing MoOxCy and the WI and HNC samples containing β-Mo2C. The two different allotropes were suggested to follow different reaction pathways, leading to small differences in the catalytic performance. However, overall, all three catalysts showed a decrease in activity (below 6%) and an increase in C2H4 selectivity (from 60 to 80 C%) with time on stream (TOS). The deactivation mechanism was suggested to be mainly due to oxidation of the carbide to MoOx and carbon deposition. Mo2C was also supported on various metal oxide materials via the wet impregnation technique. Mo2C supported on Al2O3 and ZrO2 increased initial activity (about 8% C2H6 conversion) but a faster deactivation with TOS was observed. Mo2C/Ga2O3 favoured the direct dehydrogenation reaction achieving high C2H4 selectivities (above 80 C%), but deactivation with TOS due to carbon deposition was significant. Mo2C supported on CeO2 and TiO2 had lower activity (about 3% C2H6 conversion). Oxidation to MoO2 and carbon deposition is again suggested to be the main deactivation mechanism. H2 co-feeding, on Mo2C/SiO2 and Mo2C/ZrO2, increased the stability of the catalysts but C2H4 yield was affected (from 5 to 2%). At 17 vol% H2 co-feeding, Mo2C/ZrO2 showed promising catalyst stability over a 20 h period, paralleled by a stable C2H4 yield.

Graphical abstract: Conversion of CO2 and small alkanes to platform chemicals over Mo2C-based catalysts

Associated articles

Supplementary files

Article information

Article type
Paper
Submitted
28 آذر 1399
Accepted
22 دی 1399
First published
22 دی 1399

Faraday Discuss., 2021,230, 68-86

Conversion of CO2 and small alkanes to platform chemicals over Mo2C-based catalysts

W. Marquart, M. Claeys and N. Fischer, Faraday Discuss., 2021, 230, 68 DOI: 10.1039/D0FD00138D

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