期刊
MOLECULAR CATALYSIS
卷 466, 期 -, 页码 26-36出版社
ELSEVIER SCIENCE BV
DOI: 10.1016/j.mcat.2019.01.009
关键词
CO2 hydrogenation; Methanol; Rh-doped Cu(111); Reaction mechanism; Density functional theory
资金
- National Natural Science Foundation of China [21376186, 21706203, 51762042]
- China Postdoctoral Science Foundation [2016M592794]
- Natural Science Basic Research Plan in Shaanxi Province of China [2017JQ2030]
- Fundamental Research Funds for the Central Universities (Creative Team Plan in Xi'an Jiaotong University) [cxtd2017004]
- Shaanxi Key Laboratory of Energy Chemical Process Intensification [SXECP1201703]
- Joint Laboratory of Xi'an Jiaotong Univ.
- Shaanxi Coal Chemical Industry Technology Research Institute Co. Ltd.
Self-consistent periodic density functional theory (DFT) calculations were employed to explore the adsorption and reaction mechanisms of CO2 hydrogenation to methanol via the reverse water-gas-shift pathway on Cu(111) and three RhCu(111) surfaces with different doped-Rh atoms on Cu(111) surfaces, denoted as Rh3Cu6 (111), Rh6Cu3 (111) and Rh ML surfaces. All the possible favored adsorption sites, structures and adsorption energies of the relative species on Cu(111) and RhCu(111) were determined. H2CO*, HCO*,CO*, cis-COOH* and transCOOS* adsorbing at Rh atoms through C atom are strengthened by the doped Rh, and the adsorption energies of species on Cu sites through O atom are not altered obviously, which can be explained by d-PDOS analysis. Through the analyses of Bronsted-Evans-Polanyi (BEP) relationships, it is found that the adsorption of bransCOOH* and co-adsorbed CO*/H* is stronger on RhCu(111) surfaces, while the energy of CO* in the TS geometry is dramatically decreased by doping with Rh atoms, leading to the alternation of rate-limiting step from CO2 hydrogenation forming trans-COON* on Cu(111) and Rh3Cu6 (111) surfaces to CO hydrogenation forming HCO* on Rh3Cu6 (111) and Rh ML (monolayer) surfaces. The order of the highest activation barriers for the overall reaction is Cu(111) > Rh6Cu3 (111) > Rh ML > Rh3Cu6 (111). Moreover, due to the dissociative adsorption of H-2, the yield of CO byproduct is suppressed. The calculated results show that the overall reaction process of CH3OH synthesis is facilitated kinetically and thermodynamically, especially on Rh3Cu6 (111) surface. The present insights are helpful for the rational design and optimization of Rh-Cu bimetallic catalysts used in the process of CO2 hydrogenation to CH3OH synthesis.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据