A density functional theory study on the water formation at high coverages and the water effect in the Fischer-Tropsch synthesis
Data(s) |
10/05/2004
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Resumo |
The O removal through water formation is an important process in the Fischer-Tropsch synthesis. In this study, both steps in water formation (O + H --> OH, OH + H --> H2O) are studied on the stepped Co(0001) at high coverages using density functional theory. We find the following. (i) In both O-O and O-OH co-adsorption systems, two transition states (TSs) were located for the O hydrogenation: in one TS, both O and H are on the same terrace, and in the other they are at the interface between the step edge and the terrace below. (ii) In both the O-O and O-OH co-adsorption systems, the O hydrogenation at the interface is easier (E-a = 0.32 eV in the O-O system, E-a = 1.10 eV in the O-OH system) than that on the same terrace (E-a = 1.49 eV in the O-O system, E-a = 1.80 eV in the O-OH system). (iii) In both the O-O and O-OH co-adsorption systems, only one TS for the OH hydrogenation was located, in which both OH and H are on the same terrace. (iv) Compared to the OH hydrogenation in the O-OH system (E-a = 1.46 eV), the reaction in the OH-OH system (E-a = 0.64 eV) is much easier. The barrier differences and the water effect on the Fischer-Tropsch synthesis are discussed. A possible route with low barriers for water formation is proposed. |
Identificador |
http://dx.doi.org/10.1080/00268970410001723073 http://www.scopus.com/inward/record.url?scp=4444333367&partnerID=8YFLogxK |
Idioma(s) |
eng |
Direitos |
info:eu-repo/semantics/restrictedAccess |
Fonte |
Gong , X Q , Raval , R & Hu , P 2004 , ' A density functional theory study on the water formation at high coverages and the water effect in the Fischer-Tropsch synthesis ' Molecular Physics , vol 102 (9-10) , no. 9-10 , pp. 993-1000 . DOI: 10.1080/00268970410001723073 |
Palavras-Chave | #/dk/atira/pure/subjectarea/asjc/3100/3107 #Atomic and Molecular Physics, and Optics |
Tipo |
article |