Research output per year
Research output per year
Virginia Boix, Mattia Scardamaglia, Tamires Gallo, Giulio D'Acunto, Marie Døvre Strømsheim, Filippo Cavalca, Suyun Zhu, Andrey Shavorskiy, Joachim Schnadt, Jan Knudsen
Research output: Contribution to journal › Article › peer-review
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.
Original language | English |
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Pages (from-to) | 9897-9907 |
Number of pages | 11 |
Journal | ACS Catalysis |
Volume | 12 |
Issue number | 16 |
DOIs | |
Publication status | Published - 2022 Aug 19 |
Research output: Thesis › Doctoral Thesis (compilation)