(760e) Dry Reforming of Methane Using Two-Dimensional Metal Carbides
AIChE Annual Meeting
Friday, November 15, 2019 - 9:20am to 9:40am
CH4 â C + 2H2 methane thermal degradation
2CO â CO2 + C carbon monoxide disproportionation
CO + H2O â H2 + CO2 water gas shift
These gas phase reactions severely deteriorate the catalyst performance and affects the H2/CO ratio. Several studies have been done to develop high-performance catalysts. 2, 3However, despite considerable environmental benefits, DRM is not an industrially mature process due to the high endothermic nature together with rapid catalyst deactivation, that hindered its industrialization.
Novel parameters for the preparation of the carbide catalyst are introduced and a series of 2D Vanadium carbide (V2C) catalysts are prepared to study their effect on the structural and catalytic properties. Characterization techniques such as x-ray diffraction (XRD), x-ray photoelectron microscopy (XPS), scanning electron microscopy (SEM) and Raman spectroscopy are employed to analyze the catalyst. Kinetic studies are performed in the stainless-steel reactor and the final gas analysis is done using Agilent GC equipped with flame ionization detector (FID) and thermal conductivity detector (TCD). Steady-state kinetics of bulk and two-dimensional vanadium carbide shows a stable catalytic activity and selectivity towards syngas for 2D V2C as compared to the bulk VC. Insights into the kinetic data and catalyst characterization results co-relates the kinetic data with the structure of the catalyst. The 2D V2C with hexagonal closed packing (hcp) structure exhibits remarkable catalytic/stable performance as compared to the bulk VC, which exhibits face centered cubic (fcc) structure. The difference in the structure of the carbides plays an important role in facilitating re-carburization of the catalysts. The spent catalyst is further re-carburized and similar catalytic performance is observed. It is apparent from our study that the catalytic cycle goes through the redox mechanism, where the rate for oxidation of catalyst by CO2 are in equilibrium with rate of re-carburization by CH4.
In this presentation we will demonstrate our steady-state kinetic studies in DRM reaction using 2D vanadium carbides and the bulk 3D vanadium carbides with an attempt to uncover the relationship between the structures of catalysts and its catalytic activity. Stress is being focused upon maximizing activity, selectivity, and stability towards syngas. A fundamental relationship between catalyst structural morphology and its catalytic performance is established. Redox mechanism is proposed as a driving phenomenon for enhanced and stable catalytic performance for 2D vanadium carbide.
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