Dehydrogenation and dehydration of formic acid over orthorhombic molybdenum carbide

Agrawal, Kushagra; Roldán, Alberto; Kishore, Nanda; Logsdail, Andrew J.

doi:10.1016/j.cattod.2021.04.011

Cited by 15 publications

(8 citation statements)

References 66 publications

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“…In addition, zeroth order regular approximation (ZORA) 37 scalar corrections were incorporated to account for relativistic effects. The choice of all these parameters is a result of a systematic study described previously 42 .…”

Section: Computational Detailsmentioning

confidence: 99%

Hydrodeoxygenation of guaiacol over orthorhombic molybdenum carbide: a DFT and microkinetic study

Agrawal

Roldán

Kishore

et al. 2022

Catal. Sci. Technol.

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Section: Computational Detailsmentioning

confidence: 99%

Hydrodeoxygenation of guaiacol over orthorhombic molybdenum carbide: a DFT and microkinetic study

Agrawal

Roldán

Kishore

et al. 2022

Catal. Sci. Technol.

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“…It is well known that the Mo-terminated β-Mo 2 C (100) surface exhibits a higher affinity for oxygenates ,− and we calculated a binding energy of −2.12 eV for glycerol on the clean Mo sites with the current computational setup. However, the chosen active site model (4H) (Figure a) does not possess any empty Mo site, and therefore glycerol adsorbs weakly on a Mo site ( E ZPE ads = −0.57 eV) by displacing the neighboring H atoms from the hollow sites to bridge sites as shown in the inset of Figure .…”

Section: Resultsmentioning

confidence: 99%

Active Site Identification for Glycerol Hydrodeoxygenation over the Oxygen Modified Molybdenum Carbide Surface

Ammal

Heyden

2023

ACS Catal.

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Density functional theory and microkinetic reactor modeling were used to investigate the hydrodeoxygenation (HDO) mechanism of glycerol on the oxygenated Mo2C catalyst surface to understand the activity and product selectivity under practically relevant reaction conditions. Reactor simulations with multiple active site models predicted that a fully oxygenated surface with acid–base (OH,O) pairs is active for glycerol dehydration and it can selectively cleave one C–O bond to produce 3-hydroxypropanal (HPA). The acid sites are not directly involved in the C–O bond scission process; however, surface oxygen vacancy formation is promoted in the presence of acid sites. The rate-limiting C–O bond cleavage process occurs on the exposed Mo sites with a concerted β-hydrogen transfer to the nearest conjugate base (Mo–O) via an E2 elimination mechanism. Dehydration of HPA to acrolein was observed at longer residence times. Our analysis revealed that reaction conditions, such as temperature and partial pressure of H2, can be tuned to promote further deoxygenation of HPA and acrolein to produce propanal and propylene.

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“…In addition, zeroth order regular approximation (ZORA) 35 scaler corrections were incorporated to account for relativistic effects. The choice of all these parameters is a result of a systematic study described previously 40 .…”

Section: Computational Detailmentioning

confidence: 99%

Hydrodeoxygenation of Guaiacol Over Orthorhombic Molybdenum Carbide: A DFT and Microkinetic Study

Agrawal

Roldán

Kishore

et al. 2021

Preprint

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The hydrodeoxygenation of guaiacol is modelled over a (100) β-Mo2C surface using density functional theory and microkinetic simulations. The thermochemistry of the process shows that the demethoxylation of the guaiacol, to form phenol, will be the initial steps, with a reaction energy of 29 kJ/mol (i.e. endothermic) and a highest activation barrier of 112 kJ/mol. Subsequently, the dehydroxylation of the phenol, which has a rate-determining activation barrier of 145 kJ/mol, will lead to the formation of benzene, with an overall reaction energy for conversion from guaiacol of -91 kJ/mol (i.e. exothermic). The sp 2 and sp hybridized carbon atoms of the molecular functional groups are found to dissociate on the surface with minimum energy barriers, while the hydrogenation of the adsorbed molecules requires higher energy.The microkinetic modelling, which is performed considering typical reaction conditions of 500 to 700 K, and a partial pressure ratio H2:guaiacol of 1, shows quick formation and accumulation of phenol on the surface with increasing temperature, although high temperatures mitigate the guaiacol adsorption step. Based on simulated temperature programmed desorption (TPD), maximum conversion of guaiacol can be expected at 70% surface coverage of this species.

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Dehydrogenation and dehydration of formic acid over orthorhombic molybdenum carbide

Cited by 15 publications

References 66 publications

Hydrodeoxygenation of guaiacol over orthorhombic molybdenum carbide: a DFT and microkinetic study

Hydrodeoxygenation of guaiacol over orthorhombic molybdenum carbide: a DFT and microkinetic study

Active Site Identification for Glycerol Hydrodeoxygenation over the Oxygen Modified Molybdenum Carbide Surface

Hydrodeoxygenation of Guaiacol Over Orthorhombic Molybdenum Carbide: A DFT and Microkinetic Study

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