Investigation of moOx/Al2O3 under cyclic operation for oxidative and non-oxidative dehydrogenation of propane

DOI: 10.3390/catal10121370

Authors: Santhosh K. Matam (UK Catalysis Hub, Research Complex at Harwell; Cardiff University) , Caitlin Moffat (University of Glasgow) , Pip Hellier (UK Catalysis Hub, Research Complex at Harwell; Cardiff University) , Michael Bowker (UK Catalysis Hub, Research Complex at Harwell; Cardiff University) , Ian P. Silverwood (UK Catalysis Hub, Research Complex at Harwell; ISIS Neutron and Muon Source) , C. Richard A. Catlow (UK Catalysis Hub, Research Complex at Harwell; Cardiff University; University College London) , S. David Jackson (University of Glasgow) , James Craswell (UK Catalysis Hub, Research Complex at Harwell; University of Southampton) , Peter P. Wells (UK Catalysis Hub, Research Complex at Harwell; University of Southampton; Diamond Light Source) , Stewart F. Parker (UK Catalysis Hub, Research Complex at Harwell; University of Glasgow; ISIS Neutron and Muon Source) , Emma K. Gibson (UK Catalysis Hub, Research Complex at Harwell; University of Glasgow)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Catalysts , VOL 10

State: Published (Approved)
Published: November 2020
Diamond Proposal Number(s): 10306

Abstract: A MoOx/Al2O3 catalyst was synthesised and tested for oxidative (ODP) and non-oxidative (DP) dehydrogenation of propane in a reaction cycle of ODP followed by DP and a second ODP run. Characterisation results show that the fresh catalyst contains highly dispersed Mo oxide species in the +6 oxidation state with tetrahedral coordination as [MoVIO4]2− moieties. In situ X-ray Absorption Spectroscopy (XAS) shows that [MoVIO4]2− is present during the first ODP run of the reaction cycle and is reduced to MoIVO2 in the following DP run. The reduced species are partly re-oxidised in the subsequent second ODP run of the reaction cycle. The partly re-oxidised species exhibit oxidation and coordination states that are lower than 6 but higher than 4 and are referred to as MoxOy. These species significantly improved propene formation (relatively 27% higher) in the second ODP run at similar propane conversion activity. Accordingly, the initial tetrahedral [MoVIO4]2− present during the first ODP run of the reaction cycle is active for propane conversion; however, it is unselective for propene. The reduced MoIVO2 species are relatively less active and selective for DP. It is suggested that the MoxOy species generated by the reaction cycle are active and selective for ODP. The vibrational spectroscopic data indicate that the retained surface species are amorphous carbon deposits with a higher proportion of aromatic/olefinic like species.

Journal Keywords: propane; dehydrogenation; molybdenum oxide; XANES; Raman spectroscopy; inelastic neutron scattering spectroscopy; infrared spectroscopy

Subject Areas: Chemistry


Instruments: B18-Core EXAFS

Documents:
catalysts-10-01370-v3.pdf

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