Ethylene hydrogenation on Pt(111) monitored in situ at high pressures using sum frequency generation

Paul S. Cremer;Xingcai Su;元壤 沈;Gabor A. Somorjai

University of California at Berkeley;Lawrence Berkeley National Laboratory

发表时间:1996-3-27

期 刊:Journal of the American Chemical Society

语 言:English

U R L: http://www.scopus.com/inward/record.url?scp=11044230537&partnerID=8YFLogxK

摘要

Infrared-visible sum frequency generation (SFG) has been used to monitor the surface vibrational spectrum in situ during ethylene hydrogenation on Pt(111). Measurements were made near 1 atm of total pressure of ethylene and hydrogen and at 295 K. Kinetic information was obtained simultaneously with the surface vibrational spectroscopy by monitoring the reaction rate with gas chromatography. The macroscopic turnover rate and surface adsorbate concentration could then be correlated. During the reaction ethylidyne, di-σ-bonded ethylene, ethyl, and π-bonded ethylene were observed on the surface in various amounts depending on conditions. Ethylidyne, a spectator species during hydrogenation, competed directly for sites with di-σ-bonded ethylene and its surface concentration could be shown to be completely uncorrelated with the rate of hydrogenation. In contrast, π-bonded ethylene did not compete for sites with the ethylidyne overlayer and was observed on the surface regardless of the surface concentration of ethylidyne. Evidence points to the π-bonded species as being the primary intermediate in ethylene hydrogenation on Pt(111). The surface concentration of this species is about 0.04 ML (ML = monolayer) during reaction. Thus, the turnover rate per reaction intermediate is 25 times faster than the turnover rate if measured per surface platinum atom.

相关科学

生物化学、遗传学和分子生物学
生物化学
化学工程
催化
胶体与表面化学
化学

文献指纹

医学与生命科学

Hydrogenation

ethylene

Pressure

Gas Chromatography

Hydrogen

Platinum

Spectrum Analysis

Kinetics

化合物

ethylene

Hydrogenation

Vibrational spectroscopy

Reaction intermediates

Vibrational spectra

Adsorbates

Monolayers

Gas chromatography

Reaction rates

Hydrogen

Platinum

Atoms

Infrared radiation

Monitoring

工程与材料科学

Hydrogenation

Ethylene

Vibrational spectroscopy

Reaction intermediates

Vibrational spectra

Adsorbates

Monolayers

Gas chromatography

Platinum

Reaction rates

Atoms

Infrared radiation

Hydrogen

Monitoring

被引量

期刊度量

Scopus度量

年份 CiteScore SJR SNIP
1996
1997
1998
1999 3.438 2.106
2000 3.589 2.141
2001 3.506 2.112
2002 3.587 2.324
2003 3.421 2.223
2004 3.841 2.187
2005 4.413 2.205
2006 4.662 2.229
2007 5.202 2.134
2008 5.06 2.121
2009 4.958 2.199
2010 5.167 2.14
2011 16.1 5.478 2.326
2012 17.4 6.211 2.373
2013 19.3 5.993 2.446
2014 20.9 6.294 2.568
2015 22.4 6.775 2.602
2016 23.5 7.492 2.608
2017 24 8.127 2.634
2018 24.4 7.468 2.652
2019 24.8 6.976 2.682
2020 25
2021

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