Fe3O4(001)-B表面水煤气变换反应机理第一性原理研究

采用自旋极化的密度泛函理论方法系统地研究了Fe_3O_4(001)-B表面水煤气变换的反应机理,计算了整个反应历程。结果表明,对于Fe_3O_4(001)-B表面上的水煤气变换反应,氧化还原、联合和再生三种反应路径共存,但氧化还原和联合机理的有效能垒较低,因而更占优势。对于生成H_2的基元反应,其活性受表面H浓度和催化剂表面O缺陷浓度影响;较高的表面H浓度和O缺陷浓度均有利于H_2生成。这些结果有助于进一步认识铁氧催化剂上的水煤气变换反应机理。

First-principle study on the reaction mechanism of water-gas shift on the Fe3O4 (001)-B surface

The reaction mechanism of water-gas shift (WGS) on the Fe₃O₄ (001)-B surface was systematically studied by using the density functional theory (DFT) calculation with spin polarization. The results show that for the WGS on the Fe₃O₄ (001)-B surface, three reaction routes including redox, association and regeneration ones coexist, though the redox and association routes may be more important with much lower effective energy barriers. The elementary reaction of H₂ formation is influenced by the concentrations of surface H and O defects; higher concentrations of H species and O defects on the catalyst surface are beneficial to the formation of H₂. These results should be helpful for a better understanding of the WGS reaction mechanism on the iron-oxygen catalyst.