DFT Study of Methanol Adsorption on Defect-Free CeO2 Low-Index Surfaces |
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Authors: | Dr Zhao Liu Prof Dr Charles C Sorrell Dr Pramod Koshy Dr Judy N Hart |
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Institution: | 1. Sino-French Institute of Nuclear Engineering and Technology, Sun Yat-sen University, Zhuhai, 519082 China;2. School of Materials Science and Engineering, UNSW Sydney, NSW, 2052 Australia |
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Abstract: | Methanol decomposition is a promising method for hydrogen production. However, the performance of current catalysts for this process is not sufficient for commercial applications. In this work, methanol adsorption on the CeO2 low-index surfaces is studied by density functional theory (DFT). The results show that methanol always dissociates spontaneously on the (100) surface, whereas dissociation on the (110) surface is site-selective; dissociation does not occur at all on the (111) surface, where only weak physisorption is found. The results confirm that surfaces with higher energies are more catalytically active. Analysis of the surface geometries shows that the dominant factors for the dissociation of methanol are the degree of undercoordination and the charges of the surface ions. The adsorption energy of each methanol molecule decreases with increasing coverage and there is a transition threshold between dissociative and associative adsorption. The present work indicates that a strategy to design catalysts with high activity is to maximize exposure of surfaces on which the ions have a high degree of undercoordination and a strong tendency to donate/accept electrons. The results demonstrate the importance of appropriately selecting and controlling exposed facets and particle morphology for optimizing catalyst performance. |
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Keywords: | ceria density functional theory calculations hydrogen production low-index surfaces methanol adsorption |
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