کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5424888 1395841 2008 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Examining the redox and formate mechanisms for water-gas shift reaction on Au/CeO2 using density functional theory
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
Examining the redox and formate mechanisms for water-gas shift reaction on Au/CeO2 using density functional theory
چکیده انگلیسی
We perform DFT calculations to investigate the redox and formate mechanisms of water-gas-shift (WGS) reaction on Au/CeO2 catalysts. In the redox mechanism, we analyze all the key elementary steps and find that the OH cleavage is the key step. Three possible pathways of OH cleavage are calculated: (1) OHad″+∗′→Had′+Oad″; (2) Had′+OHad″→H2(g)+Oad″+∗′; and (3) OHad″+OHad″→2Oad″+H2(g) (∗′: the free adsorption sites on the oxides; ad′: adsorption on the metal; ad″: adsorption on the oxide, respectively). In the formate mechanism, we identify all the possible pathways for the formation and decomposition of surface formates in the WGS reaction. It is found that there is a shortcoming in the redox and formate mechanisms which is related to surface oxygen reproduction. Four possible pathways for producing surface oxygen are studied, and all the barriers of the four pathways are more than 1 eV. Our results suggest that the processes to reproduce surface oxygen in the reaction circle are not kinetically easy.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Surface Science - Volume 602, Issue 17, 1 September 2008, Pages 2828-2834
نویسندگان
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