Effect of modifying impurities on magnetocatalytic and magnetoadsorption effects

Based on the theory of the sd-exchange interaction in ferromagnetics, the r elation between the magnetic state of a metal and the modifying action of i mpurities on chemisorption and catalysis was discussed. The experimental da ta were analyzed by using estimates of changes in the surface electron dens ity of the metal performed with the use of statistical-thermodynamic and qu antum-chemical models. The conditions of appearance of the magnetocatalytic and magnetoadsorption effects during the adsorption of gases on nickel and its alloys with copper and silver and also under the action of small amoun ts of modifiers, such as chemisorbed O-2, H2S, CO, C2H4, and C6H6, Were det ermined. It was found that the magnetic transition causes the modifier char ge sign to change, whereas chemisorption results in changes in the paramete rs characterizing the exchange interaction between the s- and d-electron sy stems of the metal. It is shown that the magnetocatalytic effect depends on the nature of the surface modifier: it can disappear, appear, enhance, or decrease in their presence. For the H-2 + CO and H-2 + O-chem reactions, as an example, the change in the reaction mechanism caused by the magnetic tr ansition in the presence of modifiers was found.