Adsorption of CO and kinetics of methanation over an ultradispersed powder of nickel doped with sulfur and potassium
The adsorption of CO and H2 and the kinetics of CO methanation over an ultradispersed powder (UDP) of nickel with and without promoters (sulfur and potassium) in amounts of 0.02, 0.1, and 0.2 of the monolayer coverage are experimentally studied. The magnetic properties of UDP before and after the contact with CO and the CO + H2 mixture are studied. By using the extended Hückel method (a cluster and zone versions) and the Thomas-Fermi method, changes in the two-dimensional electron density in nickel during the adsorption of sulfur and potassium and in the bond energy with CO and H are calculated. The radii of perturbing influence of S2- and K+ do not exceed 0.7 nm. The parameters of the CO adsorption and the kinetics of the CO + H2 reaction change in the presence of promoters. These changes in the cases of potassium promotion and sulfur inhibition are different.