کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
62628 47648 2007 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Methane oxidation over alumina supported platinum investigated by time-resolved in situ XANES spectroscopy
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی کاتالیزور
پیش نمایش صفحه اول مقاله
Methane oxidation over alumina supported platinum investigated by time-resolved in situ XANES spectroscopy
چکیده انگلیسی

In situ time-resolved X-ray absorption spectroscopy and mass spectrometry were used to correlate changes in catalyst surface composition with catalytic activity for methane oxidation over alumina supported Pt. Different transient experiments (i.e., pulsing of oxygen or hydrogen to an otherwise constant gas composition) were performed to study the methane oxidation kinetics. Changes in the surface O/Pt ratio were monitored by the introduction of a new analysis method of the white line area corresponding to the Pt LIII-edge XANES spectra. The relevance of the method was confirmed by first-principles calculations demonstrating how hydrogen and oxygen adsorbates modify the electronic structure of Pt. The experimental results show that during the gas-phase transients, the surface O/Pt ratio changes, which in turn affects the methane oxidation rate. Activity maxima are observed for an intermediate surface O/Pt ratio. An oxygen-rich surface seems to hinder the dissociative adsorption of methane, leading to low methane oxidation activity at oxygen excess.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Catalysis - Volume 252, Issue 1, 15 November 2007, Pages 11–17
نویسندگان
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