A density functional theory study of the adsorption behaviour of CO2 on Cu2O surfaces.
A density functional theory study of the adsorption behaviour of CO2 on Cu2O surfaces.
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DOI：
10.1063/1.4958804
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发表时间：
2016-07
期刊：
影响因子：
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通讯作者：
A. Mishra;A. Roldan;N. D. de Leeuw
中科院分区：
文献类型：
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作者：
A. Mishra;A. Roldan;N. D. de Leeuw
铜有许多应用，特别是在电催化中，铜电极的氧化状态对产物的选择性起着重要的作用。尽管铜基材料在二氧化碳还原和转化为产物方面具有明显的催化剂潜力，但对不同氧化铜表面上二氧化碳的吸附和活化的基本了解仍然有限。我们使用DFT+U方法研究了Cu2O三个最暴露（111），（110）和（001）表面的不同可能终止的表面重建。考虑到几种吸附物的几何形状，我们研究了二氧化碳在五种不同可能的末端上的吸附，并提出了二氧化碳与表面结合的八种不同构型。与早期的发现类似，CO2与最稳定的Cu2O(111):O表面结合较弱，没有分子活化，而Cu2O颗粒形态中出现的许多其他表面，则表现出较强的结合以及CO2分子的活化。研究了不同的CO2覆盖率，并给出了详细的结构和电子电荷分析。CO2分子的活化以结构转变和表面与CO2分子之间的电荷转移为特征，振动频率的显著红移进一步证实了这一点。
Copper has many applications, particularly in electro-catalysis, where the oxidation state of the copper electrode plays a significant role in the selectivity towards products. Although copper-based materials have clear potential as catalysts in the reduction of CO2 and conversion to products, fundamental understanding of CO2 adsorption and activation on different copper oxide surfaces is still limited. We have used DFT+U methodology to study the surface reconstruction of the three most exposed (111), (110), and (001) surfaces of Cu2O with different possible terminations. Considering several adsorbate geometries, we have investigated CO2 adsorption on five different possible terminations and proposed eight different configurations in which CO2 binds with the surface. Similar to earlier findings, CO2 binds weakly with the most stable Cu2O(111):O surface showing no molecular activation, whereas a number of other surfaces, which can appear in the Cu2O particles morphology, show stronger binding as well as activation of the CO2 molecule. Different CO2 coverages were studied and a detailed structural and electronic charge analysis is presented. The activation of the CO2 molecule is characterized by structural transformations and charge transfer between the surface and the CO2 molecule, which is further confirmed by considerable red shifts in the vibrational frequencies.