Fischer–Tropsch Synthesis: ZIF-8@ZIF-67-Derived\nCobalt Nanoparticle-Embedded Nanocage Catalysts

Abstract

The\npreparation of highly active and stable catalysts for syngas\nconversion is a major challenge for Fischer–Tropsch synthesis\n(FTS). Herein, we report a strategy to prepare a highly dispersed\nCo-embedded porous carbon nanocage (CoPCN) structure derived from\na core–shell metal–organic framework (MOF) ZIF-8@ZIF-67\nprecursor. High Co loading (over wt 30%) is achieved while maintaining\nan optimal dispersion and particle size of the active Co phase when\na ZIF-8@ZIF-67 is pyrolyzed at 920 °C. Besides, the porous channels\nand hollow structures of the CoPCN strengthen the diffusion of reactants\nand the hydrocarbon product, enhancing the C₅₊ selectivity\nand CO conversion. The CoPCN shows high stability in FTS with a CO\nconversion of 18.3%, 80.2% selectivity for long-chain hydrocarbons\n(C₅₊), and 8.9% selectivity for short-chain hydrocarbons\n(C₂–C₄) after 100 h time on stream. Compared\nwith other MOF-derived FTS catalysts, CoPCN-920 can achieve higher\nC₅₊ selectivity at a lower reaction temperature. The present\nwork uncovers the relationship between the porous structure and catalytic\nperformance, providing an efficient method to prepare promising materials\nfor enhanced FTS stability, activity, and selectivity.