The Synergic Effects of Iron Carbides on Conversion of Syngas to Alkenes

Understanding the relationship between iron carbide phases and their catalytic performance for iron-based Fischer-Tropsch synthesis (FTS) catalysts is crucial to design of excellent FTS catalysts. In order to eliminate the influence of other factors such as promoters, diffusion limitation and metal-inert support interaction, the iron-based catalysts with unpromoted and unsupported structure were developed to investigate the role of iron carbides in the activity and selectivity. Herein, the ratio of iron carbide species was successfully regulated under the same carburization conditions by precisely controlling the degrees of oxidation for iron metal microsphere, and the superior catalytic performance for conversion of CO to alkenes is realized at the optimal ratio of theta-Fe3C/chi-Fe5C2 = 1.5. Combining various characterization techniques, it is found that the synergistic effects of theta-Fe3C and chi-Fe5C2 plays a crucial role in the formation of alkenes. This finding not only provides a newly way to understand the role of iron carbides, but also opens an avenue for designing effective catalysts to the yield of alkenes (especially C5+ alkenes).

Automated summary

The study successfully regulated the ratio of iron carbide species, and found that the synergistic effects of theta-Fe3C and chi-Fe5C2 play a crucial role in the formation of alkenes, providing a new pathway for designing effective catalysts.