The Role of Preadsorbed Atomic Hydrogen in the NO Dissociation on a Zigzag Stepped Gold Surface: A DFT Study

• Type: Article in International Scientific Journal
• Date: 2009

Authors

Jose L C Fajin (Author) FCUP; Natalia N D S Cordeiro (Author) FCUP; Jose R B Gomes (Author) Other

Journal

Title: Journal of Physical Chemistry C

Vol. 113 No. 30

Pages: 8864-8877

ISSN: 1932-7447

Publisher: American Chemical Society

Indexing

ISI Web of Knowledge - 26 Citations

Scopus - 27 Citations

Scientific classification

FOS: Engineering and technology > Materials engineering

Other information

Authenticus ID: P-003-K1W

DOI: 10.1021/jp901266g

Abstract (EN): NO dissociation with and without the presence of hydrogen on the Au(321) surface was investigated using density functional theory and a periodic supercell approach. The role of hydrogen in the reaction of NO dissociation is studied by comparing four different routes (i.e. direct dissociation of NO on the clean surface and paths involving reaction with hydrogen adatoms prior to N-O bond cleavage). In the latter situation, two routes via a NOH intermediate were considered, producing N* + OH* or N* + H(2)O*, and another route via a NHOH intermediate was also considered, yielding NH* and OH* species. The calculations predict that the kinetically most favorable route is that producing nitrogen adatoms and water, i.e., NO* + 2H* -> N* + H(2)O* via the NOH* intermediate. This reaction is exothermic (1.1 eV) and the energy barriers for the separate NO* + H* -> NOH* and NOH* + H* -> N* + H(2)O* reactions are similar to 0.5 eV. An identical energy barrier was calculated for the reaction of the dissociation of molecular hydrogen on the stepped surface studied here, which is one-half of the barrier calculated in the case of the planar Au(111) surface. The reaction thermodynamically more favorable is that via the NHOH intermediate (1.5 eV). The kinetically least favorable path for NO dissociation on Au(321) is that occurring on the clean surface with an energy barrier of 3.5 eV; this reaction is also highly endothermic (> 2.2 eV). The present work shows that the presence of hydrogen is a necessary condition for NO dissociation on this stepped surface.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 14