CO2-REFORMING OF METHANE ON TRANSITION-METAL SURFACES

The mechanisms of CO2-reforming of methane on Cu(111), Ni(111), Pd(111 ), Pt(111), Rh(111), Ru(001), Ir(111) and Fe(110) have been investigat ed by the the unity bond index-quadratic exponential potential (UBI-QE P) method. This method was named as the bond order conservation Morse potential (BOC-MP) approach before, but it has been generalized and re named now. The heats of chemisorption (Q) for all involved adspecies, activation barriers (Delta E) and enthalpy changes (Delta H) for forwa rd and reverse reactions were evaluated. The calculations indicated th at both the dissociation of CH, and the dissociation of CO, are rate-d etermining steps and that they are promoted by each other. A small amo unt of OH radical may account for the lower activity for the CO2-refor ming of methane. The activity sequence of catalysts is Fe>Ni>Rh>Ru>Ir> Pd>Pt>Cu. The most appropriate catalyst for CO2-reforming is Ru. The m ost suitable non-noble catalyst is Ni. (C) 1998 Elsevier Science B.V. All rights reserved.