Following the Kinetics of Undercover Catalysis with APXPS and the Role of Hydrogen as an Intercalation Promoter
(2022) In ACS Catalysis 12(16). p.9897-9907- Abstract
While improved catalytic properties of many surfaces covered by two-dimensional materials have been demonstrated, a detailed in situ picture of gas delivery, undercover reaction, and product removal from the confined space is lacking. Here, we demonstrate how a combination of gas pulses with varying compositions and time-resolved ambient pressure photoelectron spectroscopy can be used to obtain such knowledge. This approach allows us to sequentially form and remove undercover reaction products, in contrast to previous work, where co-dosing of reactant gases was used. In more detail, we study CO and H2 oxidation below oxygen-intercalated graphene flakes partially covering an Ir(111) surface. We show that hydrogen rapidly mixes into a p(2... (More)
While improved catalytic properties of many surfaces covered by two-dimensional materials have been demonstrated, a detailed in situ picture of gas delivery, undercover reaction, and product removal from the confined space is lacking. Here, we demonstrate how a combination of gas pulses with varying compositions and time-resolved ambient pressure photoelectron spectroscopy can be used to obtain such knowledge. This approach allows us to sequentially form and remove undercover reaction products, in contrast to previous work, where co-dosing of reactant gases was used. In more detail, we study CO and H2 oxidation below oxygen-intercalated graphene flakes partially covering an Ir(111) surface. We show that hydrogen rapidly mixes into a p(2 × 1)-O structure below the graphene flakes and converts it into a dense OH-H2O phase. In contrast, CO exposure only leads to oxygen removal from the confined space and little CO intercalation. Finally, our study shows that H2 mixed into CO pulses can be used as a promoter to change the undercover chemistry. Their combined exposure leads to the formation of OH-H2O below the flakes, which, in turn, unbinds the flakes for enough time for CO to intercalate, resulting in a CO structure stable only in coexistence with the OH-H2O phase. Altogether, our study proves that promoter chemistry in the form of adding trace gases to the gas feed is essential to consider for undercover reactions.
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- author
- Boix, Virginia LU ; Scardamaglia, Mattia LU ; Gallo, Tamires LU ; D'Acunto, Giulio LU ; Strømsheim, Marie Døvre ; Cavalca, Filippo LU ; Zhu, Suyun LU ; Shavorskiy, Andrey LU ; Schnadt, Joachim LU and Knudsen, Jan LU
- organization
- publishing date
- 2022-08-19
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- APXPS, CO oxidation, confined catalysis, graphene, hydrogen oxidation, intercalation, undercover catalysis
- in
- ACS Catalysis
- volume
- 12
- issue
- 16
- pages
- 11 pages
- publisher
- The American Chemical Society (ACS)
- external identifiers
-
- scopus:85136149865
- ISSN
- 2155-5435
- DOI
- 10.1021/acscatal.2c00803
- language
- English
- LU publication?
- yes
- id
- eea6e5ab-bb74-48dc-a825-5ab5797cd954
- date added to LUP
- 2022-10-11 13:54:00
- date last changed
- 2023-11-21 07:18:53
@article{eea6e5ab-bb74-48dc-a825-5ab5797cd954, abstract = {{<p>While improved catalytic properties of many surfaces covered by two-dimensional materials have been demonstrated, a detailed in situ picture of gas delivery, undercover reaction, and product removal from the confined space is lacking. Here, we demonstrate how a combination of gas pulses with varying compositions and time-resolved ambient pressure photoelectron spectroscopy can be used to obtain such knowledge. This approach allows us to sequentially form and remove undercover reaction products, in contrast to previous work, where co-dosing of reactant gases was used. In more detail, we study CO and H2 oxidation below oxygen-intercalated graphene flakes partially covering an Ir(111) surface. We show that hydrogen rapidly mixes into a p(2 × 1)-O structure below the graphene flakes and converts it into a dense OH-H2O phase. In contrast, CO exposure only leads to oxygen removal from the confined space and little CO intercalation. Finally, our study shows that H2 mixed into CO pulses can be used as a promoter to change the undercover chemistry. Their combined exposure leads to the formation of OH-H2O below the flakes, which, in turn, unbinds the flakes for enough time for CO to intercalate, resulting in a CO structure stable only in coexistence with the OH-H2O phase. Altogether, our study proves that promoter chemistry in the form of adding trace gases to the gas feed is essential to consider for undercover reactions. </p>}}, author = {{Boix, Virginia and Scardamaglia, Mattia and Gallo, Tamires and D'Acunto, Giulio and Strømsheim, Marie Døvre and Cavalca, Filippo and Zhu, Suyun and Shavorskiy, Andrey and Schnadt, Joachim and Knudsen, Jan}}, issn = {{2155-5435}}, keywords = {{APXPS; CO oxidation; confined catalysis; graphene; hydrogen oxidation; intercalation; undercover catalysis}}, language = {{eng}}, month = {{08}}, number = {{16}}, pages = {{9897--9907}}, publisher = {{The American Chemical Society (ACS)}}, series = {{ACS Catalysis}}, title = {{Following the Kinetics of Undercover Catalysis with APXPS and the Role of Hydrogen as an Intercalation Promoter}}, url = {{http://dx.doi.org/10.1021/acscatal.2c00803}}, doi = {{10.1021/acscatal.2c00803}}, volume = {{12}}, year = {{2022}}, }