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Following the Kinetics of Undercover Catalysis with APXPS and the Role of Hydrogen as an Intercalation Promoter

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 orcid and Knudsen, Jan LU (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
; ; ; ; ; ; ; ; and
organization
publishing date
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}},
}