Enumeration and discrimination of mechanisms in heterogeneous catalysis based on response reactions and unity bond index-quadratic exponential potential (UBI-QEP) method

The problem of a complete enumeration of a unique set of overall reactions and the corresponding mechanisms from a given set of elementary reactions i s discussed in terms of the recently introduced concept of response reactio ns. A simple algorithm for the systematic generation of direct overall reac tions and direct mechanisms from the given set of elementary reactions is p resented. Further, based on energetic characteristics of the surface elemen tary reactions, i.e. the enthalpy changes and activation energy barriers, c alculated by using the unity bond index-quadratic exponential potential (UB I-QEP) method, a qualitative procedure for the selection of energetically t he most favorable direct mechanisms is proposed. These theoretical consider ations are illustrated by a detailed analysis of the mechanism of methanol synthesis on copper catalyst. (C) 1999 Published by Elsevier Science B.V. A ll rights reserved.