Role of Carbon Monoxide in Catalyst Reconstruction for CO Hydrogenation: First-Principles Study of the Composition, Structure, and Stability of Cu/Co(101̅2) as a Function of CO Pressure
Role of Carbon Monoxide in Catalyst Reconstruction for CO Hydrogenation: First-Principles Study of the Composition, Structure, and Stability of Cu/Co(101̅2) as a Function of CO Pressure
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DOI：
10.1021/acs.jpcc.6b09527
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发表时间：
2017-01
影响因子：
3.7
通讯作者：
Greg Collinge;N. Kruse;Jean-Sabin McEwen
中科院分区：
文献类型：
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作者：
Greg Collinge;N. Kruse;Jean-Sabin McEwen
CoCu基催化剂是大规模CO加氢制低碳醇的理想催化剂。为了模拟纳米尺寸的CoCu颗粒的Co@Cu核壳结构，我们选择了Cu/Co（1012）取向的板，并发现，与化学成像结果一致，板表面总是Cu端接的，下面是Co。使用DFT计算，我们观察到主要的表面原子交换吸附CO的存在下，与高达50%的Cu原子被替换为Co在直链步骤的板表面。没有观察到超过50%的Co原子交换。更具体地说，这项工作是通过扫描吸附的CO，表面钴，表面铜的构型空间，然后确定最低能量的表面配置。相图也被构造来确定在吸附CO的存在下施加的热力学驱动力。表面声子模式的包含被示出，以确保计算的正确性。
CoCu-based catalysts are promising candidates for the large-scale application of CO hydrogenation to higher alcohols with varying hydrocarbon chain length. To mimic the Co@Cu core–shell structure of nanosized CoCu particles, we choose a Cu/Co(1012)-oriented slab and find, in agreement with chemical imaging results, that the slab surface is always Cu-terminated, with Co underneath. Using DFT calculations, we observe major surface atom exchange in the presence of adsorbed CO, with up to 50% of the Cu atoms being replaced by Co in the straight-chain steps of the slab surface. Co atom exchange beyond 50% is not observed. More specifically, this work is accomplished by scanning the configurational space of adsorbed CO, surface Co, and surface Cu and then identifying minimum-energy surface configurations. Phase diagrams are also constructed to determine the thermodynamic driving force imposed in the presence of adsorbed CO. The inclusion of surface phonon modes is shown to ensure the correctness of the calcula...