PMID- 16570976
OWN - NLM
STAT- PubMed-not-MEDLINE
DCOM- 20070731
LR  - 20060330
IS  - 1520-6106 (Print)
IS  - 1520-5207 (Linking)
VI  - 110
IP  - 13
DP  - 2006 Apr 6
TI  - Using effusive molecular beams and microcanonical unimolecular rate theory to 
      characterize CH4 dissociation on Pt(111).
PG  - 6705-13
AB  - The dissociative sticking coefficient for CH4 on Pt(111) has been measured as a 
      function of both gas temperature (Tg) and surface temperature (Ts) using effusive 
      molecular beam and angle-integrated ambient gas dosing methods. The experimental 
      results are used to optimize the three parameters of a microcanonical 
      unimolecular rate theory (MURT) model of the reactive system. The MURT 
      calculations allow us to extract transition state properties from the data as 
      well as to compare our data directly to other molecular beam and thermal 
      equilibrium sticking measurements. We find a threshold energy for dissociation of 
      E0 = 52.5 +/- 3.5 kJ mol(-1). Furthermore, the MURT with an optimized parameter 
      set provides for a predictive understanding of the kinetics of this C-H bond 
      activation reaction, that is, it allows us to predict the dissociative sticking 
      coefficient of CH4 on Pt(111) for any combination of Ts and Tg even if the two 
      are not equal to one another, indeed, the distribution of molecular energy need 
      not even be thermal. Comparison of our results to those from recent thermal 
      equilibrium catalysis studies on CH4 reforming over Pt nanoclusters ( 
      approximately 2 nm diam) dispersed on oxide substrates indicates that the 
      reactivity of Pt(111) exceeds that of the Pt nanocatalysts by several orders of 
      magnitude.
FAU - DeWitt, Kristy M
AU  - DeWitt KM
AD  - Department of Chemistry, University of Virginia, Charlottesville, Virginia 
      22904-4319, USA.
FAU - Valadez, Leticia
AU  - Valadez L
FAU - Abbott, Heather L
AU  - Abbott HL
FAU - Kolasinski, Kurt W
AU  - Kolasinski KW
FAU - Harrison, Ian
AU  - Harrison I
LA  - eng
PT  - Journal Article
PL  - United States
TA  - J Phys Chem B
JT  - The journal of physical chemistry. B
JID - 101157530
EDAT- 2006/03/31 09:00
MHDA- 2006/03/31 09:01
CRDT- 2006/03/31 09:00
PHST- 2006/03/31 09:00 [pubmed]
PHST- 2006/03/31 09:01 [medline]
PHST- 2006/03/31 09:00 [entrez]
AID - 10.1021/jp0566865 [doi]
PST - ppublish
SO  - J Phys Chem B. 2006 Apr 6;110(13):6705-13. doi: 10.1021/jp0566865.