Please note that eDoc will be permanently shut down in the first quarter of 2021!      Home News About Us Contact Contributors Disclaimer Privacy Policy Help FAQ

Home
Search
Quick Search
Advanced
Fulltext
Browse
Collections
Persons
My eDoc
Session History
Login
Name:
Password:
Documentation
Help
Support Wiki
Direct access to
document ID:


          Institute: Fritz-Haber-Institut     Collection: Physical Chemistry     Display Documents



ID: 219338.0, Fritz-Haber-Institut / Physical Chemistry
Catalytic oxidation of ammonia on RuO2(110) surfaces: Mechanism and selectivity
Authors:Wang, Yuemin; Jacobi, Karl; Schöne, Wolf-Dieter; Ertl, Gerhard
Language:English
Date of Publication (YYYY-MM-DD):2005-03-24
Title of Journal:Journal of Physical Chemistry B
Journal Abbrev.:J. Phys. Chem. B
Volume:109
Issue / Number:16
Start Page:7883
End Page:7893
Copyright:© 2005 American Chemical Society
Review Status:Peer-review
Audience:Experts Only
Abstract / Description:The selective oxidation of ammonia to either N2 or NO on RuO2(110) single-crystal surfaces was investigated by a combination of vibrational spectroscopy (HREELS), thermal desorption spectroscopy (TDS) and steady-state rate measurements under continuous flow conditions. The stoichiometric RuO2(110) surface exposes coordinatively unsaturated (cus) Ru atoms onto which adsorption of NH3 (NH3-cus) or dissociative adsorption of oxygen (O-cus) may occur. In the absence of O-cus, ammonia desorbs completely thermally without any reaction. However, interaction between NH3-cus and O-cus starts already at 90 K by hydrogen abstraction and hydrogenation to OH-cus, leading eventually to N-cus and H2O. The N-cus species recombine either with each other to N2 or with neighboring O-cus leading to strongly held NO-cus which desorbs around 500 K. The latter reaction is favored by higher concentrations of O-cus. Under steady-state flow condition with constant NH3 partial pressure and varying O2 pressure, the rate for N2 formation takes off first, passes through a maximum and then decreases again, whereas that for NO production exhibits an S-shape and rises continuously. In this way at 530 K almost 100% selectivity for NO formation (with fairly high reaction probability for NH3) is reached.
Free Keywords:
External Publication Status:published
Document Type:Article
Communicated by:Gerhard Ertl
Affiliations:Fritz-Haber-Institut/Physical Chemistry
Identifiers:URL:http://pubs.acs.org/cgi-bin/abstract.cgi/jpcbfk/20... [Abstract]
DOI:10.1021/jp045735v
URL:http://pubs.acs.org/cgi-bin/article.cgi/jpcbfk/200... [PDF]
The scope and number of records on eDoc is subject to the collection policies defined by each institute - see "info" button in the collection browse view.