Activating the FeS (001) Surface for CO2 Adsorption and Reduction through the Formation of Sulfur Vacancies: A DFT-D3 Study
Activating the FeS (001) Surface for CO2 Adsorption and Reduction through the Formation of Sulfur Vacancies: A DFT-D3 Study
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DOI：
10.3390/catal11010127
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发表时间：
2021-01
期刊：
影响因子：
3.9
通讯作者：
N. Dzade;N. D. de Leeuw
中科院分区：
文献类型：
--
作者：
N. Dzade;N. D. de Leeuw
层状一硫化铁（FeS）是一种具有多相催化应用前景的材料，它含有活性边和惰性基面。活化FeS材料的（001）基面可以提高其对CO2活化和还原反应的催化性能。在这里，我们报告的色散校正密度泛函理论（DFT-D3）计算的吸附CO2和参与其还原通过逆水煤气变换反应的缺陷FeS（001）表面上含有硫空位的基本步骤。暴露的Fe站点产生的硫空位的创建被证明是作为高活性的网站CO2活化和还原。基于计算的吸附能，我们表明，CO2分子将胜过H2O和H2分子暴露的活性铁网站，如果所有三个分子都存在于表面上或附近。发现CO2分子的物理吸附较弱（-0.20 eV），而在缺硫的（001）表面，它的吸附更强，在含有单硫空位和双硫空位的缺陷FeS（001）表面分别释放-1.78和-1.83 eV的吸附能。CO2分子获得了显着的电荷从相互作用的表面Fe离子在缺陷表面吸附后，这导致通过振动频率分析确认的C-O键的活化。还揭示了CO2加氢反应生成CO和H2O物种的基本步骤的反应和活化能势垒。
As a promising material for heterogeneous catalytic applications, layered iron (II) monosulfide (FeS) contains active edges and an inert basal (001) plane. Activating the basal (001) plane could improve the catalytic performance of the FeS material towards CO2 activation and reduction reactions. Herein, we report dispersion-corrected density functional theory (DFT-D3) calculations of the adsorption of CO2 and the elementary steps involved in its reduction through the reverse water-gas shift reaction on a defective FeS (001) surface containing sulfur vacancies. The exposed Fe sites resulting from the creation of sulfur vacancies are shown to act as highly active sites for CO2 activation and reduction. Based on the calculated adsorption energies, we show that the CO2 molecules will outcompete H2O and H2 molecules for the exposed active Fe sites if all three molecules are present on or near the surface. The CO2 molecule is found to weakly physisorb (−0.20 eV) compared to the sulfur-deficient (001) surface where it adsorbs much strongly, releasing adsorption energy of −1.78 and −1.83 eV at the defective FeS (001) surface containing a single and double sulfur vacancy, respectively. The CO2 molecule gained significant charge from the interacting surface Fe ions at the defective surface upon adsorption, which resulted in activation of the C–O bonds confirmed via vibrational frequency analyses. The reaction and activation energy barriers of the elementary steps involved in the CO2 hydrogenation reactions to form CO and H2O species are also unraveled.