THE KINETICS OF CARBON FORMATION FROM CH4 + H2 ON A SILICA-SUPPORTED NICKEL-CATALYST

A microkinetic model for the formation of carbon on a nickel surface exposed to CH4 + H2 gas mixtures is constructed and compared with measured carbon formation rates for a Ni/SiO2 catalyst. Most of the parameters of the model are determined independently from single-crystal experiments or from ab initio calculations. Two rate constants and two chemisorption bond energies are determined by least-squares minimization. Good agreement is obtained with the experimental values. The resulting values for the bond energies are in good agreement with values obtained by experiments and ab initio calculation. The bond energies as well as the ratio of the rate constants depend only weakly on the assumed carbon coverage. © 1992.