The University of Southampton
University of Southampton Institutional Repository

Silicon microfabricated reactor for operando XAS/DRIFTS studies of heterogeneous catalytic reactions

Silicon microfabricated reactor for operando XAS/DRIFTS studies of heterogeneous catalytic reactions
Silicon microfabricated reactor for operando XAS/DRIFTS studies of heterogeneous catalytic reactions

Operando X-ray absorption spectroscopy (XAS), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and mass spectrometry (MS) provide complementary information on the catalyst structure, surface reaction mechanisms and activity relationships. The powerful combination of the techniques has been the driving force to design and engineer suitable spectroscopic operando reactors that can mitigate limitations inherent to conventional reaction cells and facilitate experiments under kinetic regimes. Microreactors have recently emerged as effective spectroscopic operando cells due to their plug-flow type operation with no dead volume and negligible mass and heat transfer resistances. Here we present a novel microfabricated reactor that can be used for both operando XAS and DRIFTS studies. The reactor has a glass-silicon-glass sandwich-like structure with a reaction channel (3000 μm × 600 μm; width × depth) packed with a catalyst bed (ca. 25 mg) and placed sideways to the X-ray beam, while the infrared beam illuminates the catalyst bed from the top. The outlet of the reactor is connected to MS for continuous monitoring of the reactor effluent. The feasibility of the microreactor is demonstrated by conducting two reactions: i) combustion of methane over 2 wt% Pd/Al2O3 studied by operando XAS at the Pd K-edge and ii) CO oxidation over 1 wt% Pt/Al2O3 catalyst studied by operando DRIFTS. The former shows that palladium is in an oxidised state at all studied temperatures, 250, 300, 350, 400 °C and the latter shows the presence of linearly adsorbed CO on the platinum surface. Furthermore, temperature-resolved reduction of palladium catalyst with methane and CO oxidation over platinum catalyst are also studied. Based on these results, the catalyst structure and surface reaction dynamics are discussed, which demonstrate not only the applicability and versatility of the microreactor for combined operando XAS and DRIFTS studies, but also illustrate the unique advantages of the microreactor for high space velocity and transient response experiments.

2044-4753
7842-7856
Venezia, B.
58a36966-1617-4374-9205-c2fa0ff11602
Cao, E.
eb7a2cac-afd2-424a-ad56-79029d7a7e00
Matam, S. K.
b75aaeab-adb8-4d57-857f-4c6ef4f7de63
Waldron, C.
74f893bb-7b67-4f67-b598-7d598cfd4085
Cibin, G.
264ed0c3-7ca3-4585-921c-fdaea31eeccc
Gibson, E. K.
33d570ea-12d6-4e0e-8f57-6339ab27fb76
Golunski, S.
c33fce3e-f994-4b55-a9df-ffa35944b44e
Wells, P. P.
bc4fdc2d-a490-41bf-86cc-400edecf2266
Silverwood, I.
e10eb33a-d38c-427b-9805-bea464dfd2cc
Catlow, C. R.A.
991cf4ff-f5ba-4e02-b061-86f31e0d1138
Sankar, G.
38b9039e-7899-467b-887a-60397cd25a5e
Gavriilidis, A.
8284f19c-ba83-442d-b78f-ee610486a5be
Venezia, B.
58a36966-1617-4374-9205-c2fa0ff11602
Cao, E.
eb7a2cac-afd2-424a-ad56-79029d7a7e00
Matam, S. K.
b75aaeab-adb8-4d57-857f-4c6ef4f7de63
Waldron, C.
74f893bb-7b67-4f67-b598-7d598cfd4085
Cibin, G.
264ed0c3-7ca3-4585-921c-fdaea31eeccc
Gibson, E. K.
33d570ea-12d6-4e0e-8f57-6339ab27fb76
Golunski, S.
c33fce3e-f994-4b55-a9df-ffa35944b44e
Wells, P. P.
bc4fdc2d-a490-41bf-86cc-400edecf2266
Silverwood, I.
e10eb33a-d38c-427b-9805-bea464dfd2cc
Catlow, C. R.A.
991cf4ff-f5ba-4e02-b061-86f31e0d1138
Sankar, G.
38b9039e-7899-467b-887a-60397cd25a5e
Gavriilidis, A.
8284f19c-ba83-442d-b78f-ee610486a5be

Venezia, B., Cao, E., Matam, S. K., Waldron, C., Cibin, G., Gibson, E. K., Golunski, S., Wells, P. P., Silverwood, I., Catlow, C. R.A., Sankar, G. and Gavriilidis, A. (2020) Silicon microfabricated reactor for operando XAS/DRIFTS studies of heterogeneous catalytic reactions. Catalysis Science and Technology, 10 (23), 7842-7856. (doi:10.1039/d0cy01608j). (In Press)

Record type: Article

Abstract

Operando X-ray absorption spectroscopy (XAS), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and mass spectrometry (MS) provide complementary information on the catalyst structure, surface reaction mechanisms and activity relationships. The powerful combination of the techniques has been the driving force to design and engineer suitable spectroscopic operando reactors that can mitigate limitations inherent to conventional reaction cells and facilitate experiments under kinetic regimes. Microreactors have recently emerged as effective spectroscopic operando cells due to their plug-flow type operation with no dead volume and negligible mass and heat transfer resistances. Here we present a novel microfabricated reactor that can be used for both operando XAS and DRIFTS studies. The reactor has a glass-silicon-glass sandwich-like structure with a reaction channel (3000 μm × 600 μm; width × depth) packed with a catalyst bed (ca. 25 mg) and placed sideways to the X-ray beam, while the infrared beam illuminates the catalyst bed from the top. The outlet of the reactor is connected to MS for continuous monitoring of the reactor effluent. The feasibility of the microreactor is demonstrated by conducting two reactions: i) combustion of methane over 2 wt% Pd/Al2O3 studied by operando XAS at the Pd K-edge and ii) CO oxidation over 1 wt% Pt/Al2O3 catalyst studied by operando DRIFTS. The former shows that palladium is in an oxidised state at all studied temperatures, 250, 300, 350, 400 °C and the latter shows the presence of linearly adsorbed CO on the platinum surface. Furthermore, temperature-resolved reduction of palladium catalyst with methane and CO oxidation over platinum catalyst are also studied. Based on these results, the catalyst structure and surface reaction dynamics are discussed, which demonstrate not only the applicability and versatility of the microreactor for combined operando XAS and DRIFTS studies, but also illustrate the unique advantages of the microreactor for high space velocity and transient response experiments.

Text
Silicon microfabricated reactor - Version of Record
Available under License Creative Commons Attribution.
Download (6MB)

More information

Accepted/In Press date: 2 October 2020

Identifiers

Local EPrints ID: 446177
URI: http://eprints.soton.ac.uk/id/eprint/446177
ISSN: 2044-4753
PURE UUID: 91817b5f-904e-4aa4-b5d3-83150aed33b2
ORCID for P. P. Wells: ORCID iD orcid.org/0000-0002-0859-9172

Catalogue record

Date deposited: 26 Jan 2021 17:31
Last modified: 27 Apr 2022 01:48

Export record

Altmetrics

Contributors

Author: B. Venezia
Author: E. Cao
Author: S. K. Matam
Author: C. Waldron
Author: G. Cibin
Author: E. K. Gibson
Author: S. Golunski
Author: P. P. Wells ORCID iD
Author: I. Silverwood
Author: C. R.A. Catlow
Author: G. Sankar
Author: A. Gavriilidis

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×