The present study investigates the details of MoS2-edge surfaces modified with different loadings of nickel and cobalt using density-functional theory (DFT) under generalized gradient approximation (GGA) considering the effect of sulfidation conditions. Although this has been the subject of previous studies, a comprehensive understanding of the promoted edge surfaces is not complete. Under typical sulfidation conditions, nickel prefers to incorporate into the metal edge and cobalt the S-edge of MoS2. On a partially promoted metal edge surface, sulfur atoms bond to the surface on top of the molybdenum atoms and the promoter atoms tend to be uncovered. The adsorbed sulfur atoms atop of molybdenum atoms and the neighboring uncovered promoter atoms provide pairs of base (or nucleophile) and acid sites for surface catalytic reactions. (C) 2004 Elsevier Inc. All rights reserved.