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Heterogeneous zeotype catalysts for the direct utilisation of CO2

Heterogeneous zeotype catalysts for the direct utilisation of CO2
Heterogeneous zeotype catalysts for the direct utilisation of CO2
Due to the increasing levels of carbon dioxide (CO2) in the atmosphere, there is a growing demand for carbon utilisation technologies. Mono- and polycarbonate materials, synthesised via the catalytic conversion of CO2 within the pores of high surface area materials, are providing opportunities for the sustainable development of carbon capture and utilisation (CCU) technologies.1 At this conference, we will present our most recent design strategies which utilise single-site organo-catalysts inside the pores of a zeotype framework for the formation of cyclic carbonates from CO2 and epoxides. (Figure 1).

Due to the coordinatively unsaturated chromium nodes and large surface area, metal organic framework (MOF) MIL-101(Cr) has been identified as a suitable host for anchoring imidazole-based organo-catalysts.2 A series of substituted imidazoles were synthesized and coordinated to the MOF at the chromium sites via the unsubstituted N-atom. The series was chosen to provide increasing steric demand in the imidazole side group. Characterisation of the catalyst was conducted by electron paramagnetic resonance (EPR) spectroscopy to probe the Cr3+ sites. EPR Spectra for bare MIL-101(Cr) matched the literature well and on binding of the imidazole to the Cr3+ sites, broadening of the resonance signals is observed.3 Further analysis will be conducted by x-ray absorption spectroscopy (XAS) and fourier transform infrared spectroscopy (FT-IR).

For the reaction of 1,2-epoxybutane with CO2, high activities were observed for all catalysts, achieving 80% conversion with 99% selectivity in 90 minutes. Complete conversion of the epoxide was reached after 6 hours. It is evident that when the imidazoles are heterogenised within the MIL-101 structure, the catalytic ability is greatly enhanced, with a highest turnover frequency (TOF) of 750 hr-1 achieved.

Imidazole grafted MIL-101(Cr) has been shown to be a promising catalyst for the transformation of CO2 to cyclic carbonates. Combing the absorptive, high surface area properties of MOFs with a targeted organic moiety, we have demonstrated the ability to produce a stable heterogeneous catalyst capable of high catalytic turnovers for CO2 utilisation.
Stewart, Daniel
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Webb, William
fb2b9d49-23f1-4645-aaf5-f92dd5f6bdad
Raja, Robert
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Potter, Matthew
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Sazio, Pier-John
0d6200b5-9947-469a-8e97-9147da8a7158
Stewart, Daniel
03dcd3ae-9a52-402a-b8d6-ab2b99c878e6
Webb, William
fb2b9d49-23f1-4645-aaf5-f92dd5f6bdad
Raja, Robert
74faf442-38a6-4ac1-84f9-b3c039cb392b
Potter, Matthew
34dee7dc-2f62-4022-bb65-fc7b7fb526d2
Sazio, Pier-John
0d6200b5-9947-469a-8e97-9147da8a7158

Stewart, Daniel, Webb, William, Raja, Robert, Potter, Matthew and Sazio, Pier-John (2017) Heterogeneous zeotype catalysts for the direct utilisation of CO2. British Zeolite Association - Annual Meeting 2017, University of Central Lancashire, United Kingdom. 1 pp .

Record type: Conference or Workshop Item (Other)

Abstract

Due to the increasing levels of carbon dioxide (CO2) in the atmosphere, there is a growing demand for carbon utilisation technologies. Mono- and polycarbonate materials, synthesised via the catalytic conversion of CO2 within the pores of high surface area materials, are providing opportunities for the sustainable development of carbon capture and utilisation (CCU) technologies.1 At this conference, we will present our most recent design strategies which utilise single-site organo-catalysts inside the pores of a zeotype framework for the formation of cyclic carbonates from CO2 and epoxides. (Figure 1).

Due to the coordinatively unsaturated chromium nodes and large surface area, metal organic framework (MOF) MIL-101(Cr) has been identified as a suitable host for anchoring imidazole-based organo-catalysts.2 A series of substituted imidazoles were synthesized and coordinated to the MOF at the chromium sites via the unsubstituted N-atom. The series was chosen to provide increasing steric demand in the imidazole side group. Characterisation of the catalyst was conducted by electron paramagnetic resonance (EPR) spectroscopy to probe the Cr3+ sites. EPR Spectra for bare MIL-101(Cr) matched the literature well and on binding of the imidazole to the Cr3+ sites, broadening of the resonance signals is observed.3 Further analysis will be conducted by x-ray absorption spectroscopy (XAS) and fourier transform infrared spectroscopy (FT-IR).

For the reaction of 1,2-epoxybutane with CO2, high activities were observed for all catalysts, achieving 80% conversion with 99% selectivity in 90 minutes. Complete conversion of the epoxide was reached after 6 hours. It is evident that when the imidazoles are heterogenised within the MIL-101 structure, the catalytic ability is greatly enhanced, with a highest turnover frequency (TOF) of 750 hr-1 achieved.

Imidazole grafted MIL-101(Cr) has been shown to be a promising catalyst for the transformation of CO2 to cyclic carbonates. Combing the absorptive, high surface area properties of MOFs with a targeted organic moiety, we have demonstrated the ability to produce a stable heterogeneous catalyst capable of high catalytic turnovers for CO2 utilisation.

Text
BZA2017 Abstract D.J.Stewart R.Raja - Accepted Manuscript
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More information

Published date: 10 April 2017
Venue - Dates: British Zeolite Association - Annual Meeting 2017, University of Central Lancashire, United Kingdom, 2017-04-09

Identifiers

Local EPrints ID: 418170
URI: http://eprints.soton.ac.uk/id/eprint/418170
PURE UUID: cdb1a865-1c07-4ebf-a189-ecaeac6bae42
ORCID for Daniel Stewart: ORCID iD orcid.org/0000-0003-3409-6517
ORCID for Robert Raja: ORCID iD orcid.org/0000-0002-4161-7053
ORCID for Matthew Potter: ORCID iD orcid.org/0000-0001-9849-3306
ORCID for Pier-John Sazio: ORCID iD orcid.org/0000-0002-6506-9266

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Date deposited: 23 Feb 2018 17:30
Last modified: 07 Oct 2020 08:15

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Contributors

Author: Daniel Stewart ORCID iD
Author: William Webb
Author: Robert Raja ORCID iD
Author: Matthew Potter ORCID iD
Author: Pier-John Sazio ORCID iD

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