Nanoporous Carbon Catalysts in Fischer–Tropsch Synthesis

Ordered mesoporous carbons have emerged as versatile supports for Fischer–Tropsch catalysts due to their high surface area, tunable pore architectures, and chemical stability. However, the influence of active-metal identity on product selectivity within a common carbon framework remains insufficiently understood, particularly when Fe and Co are compared under rigorously identical conditions. To address this aspect, we prepared Fe- and Co-based catalysts with comparable nominal metal loadings supported on CMK-5 carbon material and evaluated their structural, surface, and catalytic properties. Comprehensive characterization revealed distinct metal-dependent behaviors, and catalytic testing between 423 and 598 K at 2 MPa showed that the catalyst CMK-5(Co10) exhibited substantially higher activity, whereas CMK-5(Fe10) provided a more stable product distribution and exclusively paraffinic C2–C3 products across the studied temperature range. In contrast, CMK-5(Co10) displayed a pronounced temperature-dependent selectivity, with increasing methane formation and the emergence of olefinic C2–C3 species at intermediate and high temperatures. Chain-growth probabilities were consistent with these trends. Complementary Density Functional Theory and Kinetic Monte Carlo analyses indicated stronger binding of carbonaceous intermediates on Fe clusters and more accessible C–C coupling pathways on Co clusters. Together, these results clarify how active-metal identity governs selectivity within a shared CMK-5 architecture and provide guidelines for designing carbon-supported Fischer–Tropsch catalysts with controlled product distributions.