The Reaction Mechanism and Its Kinetic Model of CO2 Reforming with CH4 over Ni-Mg15@HC Catalyst

In this paper, the kinetic of CO 2 dry reforming with CH 4 (DRM) over the Ni-Mg15@HC catalyst was studied after excluding the influence of internal and external mass transfer at 700–850 °C. At the same time, the partial pressures of CH 4 and CO 2 were varied from 10 to 50 kPa. The experimental results demonstrated that the reaction rate was sharply increased with the increase of CH 4 partial pressure, while the increase of CO 2 partial pressure led to a relative increase of the reaction rate. Therefore, it could be said that CH 4 dissociation was the rate determining step for DRM reaction. Moreover, the apparent activation energy of CH 4 consumption (48.6 kJ/mol) during DRM reaction was higher than that of CO 2 consumption (30.1 kJ/mol), which also confirmed the above assumption. On the basis of the reaction mechanism, a Langmuir–Hinshelwood kinetic rate model was developed, and the kinetic parameters were also estimated by the nonlinear least square regression method. The developed model could satisfactorily fit the experimental data, and R2 was as high as 0.965. Graphic Abstract The apparent activation energy of CH 4 consumption during DRM reaction was higher than that of CO 2 , then the rate determining step was determined. A kinetic rate model was developed, which could well describe the experiment.