| Autor: |
Luo, Dan, Liu, Xingchen, Chang, Tong, Bai, Jiawei, Guo, Wenping, Zheng, Wentao, Wen, Xiaodong |
| Zdroj: |
Physical Chemistry Chemical Physics (PCCP); 2/14/2024, Vol. 26 Issue 6, p5704-5712, 9p |
| Abstrakt: |
In Fischer–Tropsch synthesis (FTS), the cobalt catalyst has higher C5+ and lower CH4 selectivity in the hcp phase than in the fcc phase. However, a detailed explanation of the intrinsic mechanism is still missing. The underlying reason was explored combining density functional theory, Wulff construction, and a particle-level descriptor based on the slab model of surfaces that are prevalent in the Wulff shape to provide single-particle level understanding. Using a particle-level indicator of the reaction rates, we have shown that it is more difficult to form CH4 on hcp-Co than on fcc-Co, due to the larger effective barrier difference of CH4 formation and C–C coupling on hcp-Co particles, which leads to the lower CH4 selectivity of hcp-Co in FTS. Among the exposed facets of fcc-Co, the (311) surface plays a pivotal role in promoting CH4 formation. The reduction of CH4 selectivity in cobalt-based FTS is achievable through phase engineering of Co from fcc to hcp or by tuning the temperature and size of the particles. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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