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CO adsorption on MnO(100): Experimental benchmarks compared to DFT
Surface Science ( IF 2.1 ) Pub Date : 2021-01-27 , DOI: 10.1016/j.susc.2021.121808
Han Chen , David F. Cox

CO adsorption on the MnO(100) surface was studied using temperature programmed desorption (TPD) and density functional theory (DFT). TPD results show that CO is weakly-bound on MnO(100), with an experimental adsorption energy of -35.6 ± 2.1 kJ/mol at terrace sites in the low coverage limit. PBE simulations suggest that CO adsorption causes an implausible (2 × 2) surface reconstruction. PBE+U simulations show no signs of surface reconstruction, and provide an accurate estimate of the adsorption energy (-36.4 kJ/mol) when combined with the DFT-D3 method with Becke-Jonson damping to correct for van der Waals interactions. This simulation also shows that CO adsorbs C-down onto the Mn2+ terrace site in a tilted geometry, which is also observed experimentally and computationally on the similarly-structured NiO(100) transition metal oxide surface. TPD results for large doses show a plateauing of the coverage at about 0.4 monolayers of CO at 85 K, with a defect coverage equivalent to 0.08 monolayers. Adsorption associated with defect sites is indicated by a high-temperature desorption tail which is not satisfactorily explained by DFT simulations of simple step or oxygen vacancy defects.



中文翻译:

MnO(100)上的CO吸附:与DFT相比的实验基准

使用程序升温解吸(TPD)和密度泛函理论(DFT)研究了MnO(100)表面上的CO吸附。TPD结果表明,CO在MnO(100)上弱结合,在低覆盖范围的梯田部位,实验吸附能量为-35.6±2.1 kJ / mol。PBE模拟表明,CO吸附会导致难以置信的(2×2)表面重建。PBE + U模拟没有显示出表面重建的迹象,当结合DFT-D3方法和Becke-Jonson阻尼来校正范德华相互作用时,可以准确估计吸附能(-36.4 kJ / mol)。该模拟还表明,CO将C-向下吸附到Mn 2+上。倾斜的几何形状中的平台位置,在相似结构的NiO(100)过渡金属氧化物表面上也通过实验和计算观察到。大剂量的TPD结果显示,在85 K时,约0.4单层CO的覆盖率达到稳定水平,缺陷覆盖率等于0.08单层。高温脱附尾部表明了与缺陷部位相关的吸附,而简单步骤或氧空位缺陷的DFT模拟未能令人满意地解释该现象。

更新日期:2021-02-07
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