Preparation of Ni-Co/SiO2 catalyst by ammonia reflux impregnation and its CH4-CO2 reforming reaction performance

A series of Ni-Co/SiO2 catalysts were synthesized through a novel ammonia reflux impregnation method for application in the CH4-CO2 reforming reaction. The prepared catalysts were characterized by XRD, SEM-EDS, NH3-TPD, H-2-TPR, N-2 physisorption analysis, XPS, TEM, IR and TG-DSC. The activity of the catalyst was evaluated by a fixed-bed continuous reactor. The results exhibited that refluxing with ammonia water in the catalyst preparation process can regulate the particle size and dispersion of bimetallic phase, and further enhance the interaction between active metal phase and carrier. Moreover, the Ni-Co/SiO2 bimetallic catalyst can significantly improve the activity and of CH4-CO2 reforming reaction and provide high stability and carbon deposition resistance performance. The active metal phase Ni and Co with the molar ratio of 4:1 by ammonia reflux impregnation had the better reaction performance than catalysts prepared by equal volume impregnation method, with the highest conversion of CH4 (86.22%), CO2 (87.93%) and the least carbon deposition (0.88%). The improvement of the reactivity should be due to the synergistic effect of Ni and Co of the catalyst.