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A novel two-stage catalyst combinationsystem for CO hydrogenationwas applied. First, the thermal coupling conditions between modifiedFisher–Tropsch (FT) synthesis catalyst Cu25Fe22Co3K3/SiO2and methanolsynthesis catalyst Cu/ZnO/Al2O3were investigated.Then, the loading mode and volume of Cu/ZnO/Al2O3and Cu25Fe22Co3K3/SiO2catalyst combination system for lower alcohols synthesiswas optimized. The obtained thermal coupling conditions were as follows:(reduction conditions) T= 400 °C, P= 0.5 MPa, and GSHV = 840 h–1; (reaction conditions) T= 280 °C, P= 5.5 MPa, and GSHV= 2800 h–1. Under these conditions, the per-passconversion of CO and yield of lower alcohols reached 48.3% and 492.0g kg–1h–1, respectively, overthe two-stage bed catalyst combination system of Cu25Fe22Co3K3/SiO2(2.5 mL)//Cu/ZnO/Al2O3(2.5 mL). It was indicated that the combinedloading mode in a two-stage bed reactor showed better catalytic performancesthan single or mixed loading mode in a single bed reactor. Througha lumped kinetics study over the Cu25Fe22Co3K3/SiO2(2.5 mL)//Cu/ZnO/Al2O3(2.5 mL) two-stage bed catalyst combination system,this can be due to the improvement of methanol synthesis over thelower Cu/ZnO/Al2O3catalyst which was promotedby the generated CO2from the upper Cu25Fe22Co3K3/SiO2catalyst. [ABSTRACT FROM AUTHOR]