Reaction Rate Enhancement in Nanoporous Materials with Single-File Behaviour

Abstract

In the concept of ´´molecular traffic control´´, Derouane and Gabelica postulated an enhancement of the effective conversion rate in catalytic reactions if the reactant and product molecules avoid each other by preferentially choosing different channel systems on their diffusion path into and out of the catalyst particles. After two decades of controversial discussions, the feasibility of this concept has recently been demonstrated by considering a network of intersecting single-file channels, whose accessibility by the reactant and product molecules was mutually excluded. The present communication analyses the dependence of molecular distribution over the different elements of the channel system on the intrinsic reactivity and the pore filling factor. The obtained patterns are compared with those of a reference system where all channels are equally accessible by the reactant and product molecules. Special attention is given to the effect of particle self-blockages under molecular traffic control, which occurs for large intrinsic reactivities and pore filling factors. It is demonstrated that under these conditions the simulations end up in an immobilised state which is a function of the particular simulation run. Such a behaviour is not observable in the reference system.