CO adsorption and oxidation at room temperature on graphene synthesized on atomically clean Pt(001)
| Autor: | Cristian M. Teodorescu, Ioana Cristina Bucur, Nicoleta G. Apostol, Cristian A. Tache, G. A. Lungu |
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| Rok vydání: | 2021 |
| Předmět: |
Materials science
Graphene Binding energy Analytical chemistry chemistry.chemical_element 02 engineering and technology General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Catalysis XANES 0104 chemical sciences law.invention chemistry.chemical_compound chemistry X-ray photoelectron spectroscopy law Monolayer 0210 nano-technology Platinum Carbon Carbon monoxide |
| Zdroj: | Catalysis Today. 366:155-163 |
| ISSN: | 0920-5861 |
| DOI: | 10.1016/j.cattod.2020.02.006 |
| Popis: | Carbon monoxide is adsorbed at room temperature on graphene formed on atomically clean Pt(001)–hex by chemical vapor deposition, starting with ethylene, in ultrahigh vacuum. The graphene formation is characterized in situ by high resolution photoelectron spectroscopy (HRPES), by low energy electron diffraction (LEED) and by near-edge X-ray absorption fine structure (NEXAFS). The formation of graphene destroys the hex reconstruction of Pt(001) and graphene exhibits totally in-plane sp2 bonding. CO adsorption is characterized by HRPES and a rigid shift towards higher binding energies by about 96 meV is experienced by Pt 4f core levels, together with a shift towards lower binding energy by 36 meV of the C 1s level corresponding to graphene, while the amplitude analysis of carbon and platinum peaks suggests the intercalation of carbon oxide between graphene and the metal substrate. The presence of oxidized carbon is evidenced by a separate component in the C 1s spectrum (attributed to carbon bond to oxygen) and by the occurrence of the O 1s signal. The coverage expressed in terms of the ratio of the integral amplitudes of the carbon bond to oxygen to the amplitude of the carbon from graphene approaches 3 %, yielding a CO coverage of Pt(001) of about 0.12 monolayer. The derived atomic ratio (O 1s):(C 1s bond to O) is initially close to 1, then evolves in time towards values close to 2, which means that CO is progressively oxidized upon adsorption and irradiation with soft X-rays. The relative amount of oxygen and oxidized carbon decreases in time under irradiation with soft X-rays. Weakly bound graphene on incommensurate metal surfaces may be used as atomic scale nanoreactors for trapping and immediate oxidation of carbon monoxide. |
| Databáze: | OpenAIRE |
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