Observing the oxidation of platinum.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 28874734.
- Also identified by DOI 10.1038/s41467-017-00643-z and PMC identifier 5585323.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Despite its importance in oxidation catalysis, the active phase of Pt remains uncertain, even for the Pt(111) single-crystal surface. Here, using a ReactorSTM, the catalytically relevant structures are identified as two surface oxides, different from bulk α-PtO<sub>2</sub>, previously observed. They are constructed from expanded oxide rows with a lattice constant close to that of α-PtO<sub>2</sub>, either assembling into spoked wheels, 1-5 bar O<sub>2</sub>, or closely packed in parallel lines, above 2.2 bar. Both are only ordered at elevated temperatures (400-500 K). The triangular oxide can also form on the square lattice of Pt(100). Under NO and CO oxidation conditions, similar features are observed. Furthermore, both oxides are unstable outside the O<sub>2</sub> atmosphere, indicating the presence of active O atoms, crucial for oxidation catalysts.Improving platinum as an oxidation catalyst requires understanding its structure under catalytic conditions. Here, the authors discover that catalytically important surface oxides form only when Pt is exposed to high pressure and temperature, highlighting the need to study catalysts in realistic environments.