Co₂C nanoprisms exhibit promising catalytic performance for Fischer-Tropsch synthesis to olefins (FTO) but with high CO₂ selectivity (>40%). Herein, silica-coated CoMn-based catalyst was designed to limit CO₂ production and remained Co₂C nanoprisms as active sites unchanged. With a desired coating amount of silica, CO₂ selectivity was significantly suppressed to 15.1 C% while enhancing olefins selectivity from 39.7 C% to 58.8 C%, which also shows at least 160 h of stability. It is suggested the silica-coating not only reduces the adsorption capacity of H₂O, but also promotes the fast transfer of H₂O away from active sites due to the higher adsorption energy of H₂O on SiO₂ surface, thus suppressing water-gas-shift-reaction (WGSR) activity. Moreover, the sodium promoter can counteract the H₂-enrichment effect caused by SiO₂-coating and largely restrain CH₄ formation and olefins hydrogenation. This work provides an effective strategy to suppress CO₂ formation and enhance the carbon efficiency of FTO process.

Co ₂ C 纳米棱柱在费-托合成烯烃（FTO）方面表现出有希望的催化性能，但具有高CO ₂选择性（> 40％）。在此，二氧化硅包覆的 CoMn 基催化剂旨在限制 CO _{2 的}产生并保持 Co ₂ C 纳米棱柱作为活性位点不变。使用所需的二氧化硅涂层量，CO ₂选择性被显着抑制到 15.1 C%，同时将烯烃选择性从 39.7 C% 提高到 58.8 C%，这也显示出至少 160 小时的稳定性。建议二氧化硅涂层不仅降低了 H ₂ O的吸附能力，而且促进了 H ₂的快速转移由于 H ₂ O 在 SiO ₂表面上的较高吸附能，O 远离活性位点，从而抑制水煤气变换反应 (WGSR) 活性。此外，钠促进剂可以抵消由SiO ₂涂层引起的H ₂富集效应并在很大程度上抑制CH ₄形成和烯烃加氢。这项工作提供了一种有效的策略来抑制 CO _{2 的}形成并提高 FTO 过程的碳效率。