深入了解 Cu(100) 和 Co 改性 Cu(100) 表面上 CO2 和 CO 甲烷化的机制：DFT 研究,Applied Surface Science

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深入了解 Cu(100) 和 Co 改性 Cu(100) 表面上 CO2 和 CO 甲烷化的机制：DFT 研究
Applied Surface Science ( IF 6.3 ) Pub Date : 2019-11-01 , DOI: 10.1016/j.apsusc.2019.07.199
Mei Qiu , Huilin Tao , Yi Li , Yangfan Zhang

摘要通过密度泛函理论计算研究了纯Cu(100)和Co Cu双金属催化剂上CO2和CO甲烷化的机理。获得了最有利的 CO2 和 CO 加氢途径。对于Cu(100)表面，HCOO*和CO*加氢的限速步骤的势垒分别为122.52 kJ/mol和106.14 kJ/mol。由于 H2CO* 加氢的势垒 (77.34 kJ/mol) 大于 54.80 kJ/mol 的解吸能，因此 H2CO 气体是 CO2 和 CO 在纯 Cu(100) 表面加氢的主要产物。对于 Co4/Cu(100) 表面，CO2 和 CO 甲烷化的最佳途径与 Cu(100) 表面相同。CO2 和 CO 甲烷化的限速步骤是 H2COO*（屏障为 103.57 kJ/mol）和 H2CO* 氢化（屏障为 107。80 kJ/mol)。与 CO2 和 CO 在 Cu(100) 上的机制相比，Co 掺杂剂可以修改限速步骤并降低激活势垒。特别是，H2COH 分解的势垒从 100.96 kJ/mol 变为 69.81 kJ/mol（CO2 途径）和 61.26 kJ/mol（CO 途径）。此外，共吸附的 OH* 基团会影响一些中间体的氢化途径，而不是电子结构。

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Insight into the mechanism of CO2 and CO methanation over Cu(100) and Co-modified Cu(100) surfaces: A DFT study

Abstract Density functional theory calculations were carried out to investigate the mechanism of CO2 and CO methanation over pure Cu(100) and Co Cu bimetallic catalysts. The most favorable pathways for the CO2 and CO hydrogenation were obtained. For the Cu(100) surface, the barriers of the rate-limiting step for the HCOO* and CO* hydrogenation were 122.52 kJ/mol and 106.14 kJ/mol. Because the barrier (77.34 kJ/mol) for the H2CO* hydrogenation is more than the desorption energy of 54.80 kJ/mol, H2CO gas was the main product from the hydrogenation of CO2 and CO on a pure Cu(100) surface. For the Co4/Cu(100) surface, the optimal pathways for the CO2 and CO methanation were the same as those on the Cu(100) surface. The rate-limiting step for CO2 and CO methanation is the H2COO* (barrier of 103.57 kJ/mol) and H2CO* hydrogenation (barrier of 107.80 kJ/mol). Compared to the mechanism of CO2 and CO over Cu(100), the Co dopant can modify the rate-limiting step and decrease the activation barrier. Particularly, the barrier for the H2COH decomposition was changed from 100.96 kJ/mol to 69.81 kJ/mol (CO2 pathway) and 61.26 kJ/mol (CO pathway). Furthermore, the co-adsorbed OH* group affects the hydrogenation pathway of some intermediates rather than electronic structures.

更新日期：2019-11-01

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