Nano letters, 2014-06, Vol.14 (6), p.3570-3576
2014
Volltextzugriff (PDF)
Details
- Autor(en) / Beteiligte
- Titel
- Atomic Layer-by-Layer Deposition of Pt on Pd Nanocubes for Catalysts with Enhanced Activity and Durability toward Oxygen Reduction
- Ist Teil von
- Nano letters, 2014-06, Vol.14 (6), p.3570-3576
- Ort / Verlag
- Washington, DC: American Chemical Society
- Erscheinungsjahr
- 2014
- Quelle
- Alma/SFX Local Collection
- Beschreibungen/Notizen
- An effective strategy for reducing the Pt content while retaining the activity of a Pt-based catalyst is to deposit the Pt atoms as ultrathin skins of only a few atomic layers thick on nanoscale substrates made of another metal. During deposition, however, the Pt atoms often take an island growth mode because of a strong bonding between Pt atoms. Here we report a versatile route to the conformal deposition of Pt as uniform, ultrathin shells on Pd nanocubes in a solution phase. The introduction of the Pt precursor at a relatively slow rate and high temperature allowed the deposited Pt atoms to spread across the entire surface of a Pd nanocube to generate a uniform shell. The thickness of the Pt shell could be controlled from one to six atomic layers by varying the amount of Pt precursor added into the system. Compared to a commercial Pt/C catalyst, the Pd@Pt nL (n = 1–6) core–shell nanocubes showed enhancements in specific activity and durability toward the oxygen reduction reaction (ORR). Density functional theory (DFT) calculations on model (100) surfaces suggest that the enhancement in specific activity can be attributed to the weakening of OH binding through ligand and strain effects, which, in turn, increases the rate of OH hydrogenation. A volcano-type relationship between the ORR specific activity and the number of Pt atomic layers was derived, in good agreement with the experimental results. Both theoretical and experimental studies indicate that the ORR specific activity was maximized for the catalysts based on Pd@Pt2–3L nanocubes. Because of the reduction in Pt content used and the enhancement in specific activity, the Pd@Pt1L nanocubes showed a Pt mass activity with almost three-fold enhancement relative to the Pt/C catalyst.
- Sprache
- Englisch
- Identifikatoren
- ISSN: 1530-6984eISSN: 1530-6992DOI: 10.1021/nl501205jTitel-ID: cdi_osti_scitechconnect_1396241
- Format
- –
- Schlagworte
- bimetallic catalyst, Catalysis, Catalysts, Catalytic methods, Condensed matter: electronic structure, electrical, magnetic, and optical properties, Condensed matter: structure, mechanical and thermal properties, core−shell nanostructure, Cross-disciplinary physics: materials science, rheology, Deposition, Durability, Electron states, Exact sciences and technology, fuel cell, INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY, Low-dimensional structures (superlattices, quantum well structures, multilayers): structure, and nonelectronic properties, MATERIALS SCIENCE, Methods of electronic structure calculations, Methods of nanofabrication, Nanocrystalline materials, Nanoscale materials and structures: fabrication and characterization, Nanostructure, oxygen reduction reaction, Palladium, Physics, Platinum, Platinum-based catalyst, Reduction, Surfaces and interfaces, thin films and whiskers (structure and nonelectronic properties)