期刊
CHEMISTRY-A EUROPEAN JOURNAL
卷 19, 期 4, 页码 1335-1345出版社
WILEY-V C H VERLAG GMBH
DOI: 10.1002/chem.201201106
关键词
carbon; density functional calculations; hydrogen; nanoparticles; palladium; surfaces and interfaces
资金
- Spanish MICINN [FIS2008-02238]
- Generalitat de Catalunya [2009SGR1041, XRQTC]
- MICINN [JCI-2010-06372]
- Ministerio de Educacion [SB2010-0172]
- FP7 project BeyondEverest
- Verband der Chemischen Industrie
- ICREA Funding Source: Custom
Palladium is crucial for industry-related applications such as heterogeneous catalysis, energy production, and hydrogen technologies. In many processes, atomic H and C species are proposed to be present in the surface/near-surface area of Pd, thus noticeably affecting its chemical activity. This study provides a detail and unified view on the interactions of the H and C species with Pd nanoparticles (NPs), which is indispensable for insight into their catalytic properties. Density functional calculations of the interplay of C and H atoms at various concentrations and sites on suitable Pd NPs have been performed, accompanied by catalysis-relevant experiments on oxide-supported bare and C-modified Pd NPs. It is shown that on a Pd79 NP a subsurface C atom destabilizes nearby atoms H at low coverage. Our experiments confirm that H atoms bind more weakly on C-containing Pd NPs than on C-free NPs. Various factors related to the presence of both H and C atoms on a Pd79 surface, which may influence the penetration of H atoms from the surface into the subsurface area, have been investigated. Carbon atoms facilitate the subsurface penetration of atomic H both thermodynamically and kinetically when the surface is densely covered by H atoms. Moreover, subsurface H atoms are also energetically favored, even in the absence of C atoms, when several facets of the NP are covered by H atoms.
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