Electronegative additives and poisoning in catalysis

This review presents recent surface science model studies aiming to provide a fundamental understanding of the mechanism of the poison action on metal catalysts. It contains a brief description of (1) the interaction of electronegative adatoms (S, P, Cl, C, N, etc.) with single crystal metal surfaces; (2) the chemisorptive properties of the metal surfaces modified with different amounts of electronegative additives; (3) the effect of the modifiers on some surface reactions carried out in model systems, and (4) the current theoretical approaches attempting to describe the mechanism of the poisonʹs action. The discussion is focused on the contribution of different factors to the strength of the poisoning effect and the observed correlations between the modifier-induced changes in the chemisorptive properties of the catalyst and its catalytic activity and selectivity.