Fischer-Tropsch Synthesis over Cobalt/CNTs Catalysts: Functionalized Support and Catalyst Preparation Effect on Activity and Kinetic Parameters

The effect of carbon nanotubes (CNTs) functionalization as a support on cobalt catalyst activity in Fischer Tropsch synthesis (FTS) was investigated. The CNTs functionalized with hydrogen peroxide and sonicated via a pulsing method with different pulse time. The cobalt catalysts synthesized by the impregnation method. Confinement of concise Co particle inside the functionalized CNTs at a shorter time of sonication (Co/FCNTs-10 with 10-s pulses of sonication) was confirmed by TEM analysis. The Co/FCNTs-10 catalyst show higher FTS activity than nonsonicated Co/CNTs and Co/FCNTs-20 with 20-s pulses of sonication. The activation energies obtained through the kinetic-results for FTS reaction over Co/FCNTs-10, Co/FCNTs-20, and Co/CNTs are 92.1, 98.8, and 102.7 kJ/mol. The heat of hydrogen adsorption is calculated -40.8, -34.2, and -21.4 (kJ/mol) for Co/CNTs, Co/FCNTs-20 and Co/FCNTs-10 catalysts, respectively. Co/FCNTs-10 catalyst shows higher hydrogen spillover than nonsonicated Co/CNTs catalyst.