Kinetic characterization of the reduction of silica supported cobalt catalysts

作者：Wan Y J; Li J L^*; Chen D H

来源：Journal of Thermal Analysis and Calorimetry, 2007, 90(2): 415-419.

DOI：10.1007/s10973-006-7901-y

• cobalt catalyst
• Fischer-Tropsch synthesis
• kinetic parameters
• reduction
• thermal analysis

The reduction process of silica supported cobalt catalyst was studied by thermal analysis technique. The reduction of the catalyst proceeds in two steps:
Co3O4+H-2 -> 3CoO+H2O, 3CoO+3H(2)-> 3Co+3H(2)O
which was validated by the TPR and in-situ XRD experiments. The kinetic parameters of the reduction process were obtained with a comparative method. For the first step, the activation energy, E-a and the pre-exponential factor, A, were found to be 104.35 kJ mol(-1) and 1.18.10(6)similar to 2.45.10(9) s(-1) respectively. The kinetic model was random nucleation and growth and the most probable mechanism function was found to be f(alpha)=3/2(1-alpha)[-ln(1-(alpha)](1/3) or in the integral forrn: g(alpha)=[-In(1-alpha)](2/3). For the second step, the activation energy, E-a, and the pre-exponential factor, A, were found to be 118.20 kJ mol(-1) and 1.75.10(7)similar to 2.45.10(9) s(-1) respectively. The kinetic model was a second order reaction and the probable mechanism function was f(alpha)=(1-alpha)(2) or in the integral form: g(alpha)=[1-alpha](-1)-1.

• 出版日期2007-11
• 单位中央民族大学; 中南民族大学