Highly-loaded and well-dispersed Fe5C2 nanoparticles within ordered mesoporous carbon CMK-3 (Fe5C2@CMK-3) were prepared via a simple melt infiltration method. They were successfully applied to high-temperature Fischer-Tropsch synthesis, and showed high CO conversion (91%) and activity (5.1 x 10(-4) mol(co) g(Fe)(-1) s(-1)) as well as good selectivity (38 wt%) for gasoline-range hydrocarbons (C-5-C-12). The catalytic property of Fe5C2@CMK-3 was newly interpreted, based on theoretical data obtained by computational simulations. (C) 2017 Elsevier Inc. All rights reserved.