Title : The Hydrogen Spillover Effect. Fundamental Aspects
Abstract:
In this paper we examine the controversy over the hydrogen spillover effect (HSPE) on metal catalysts supported on non-reducible oxides. We propose that hydrogen spiltover species would consist in H/OH pairs, produced by an interfacial dehydroxylation then diffusing over the support by a thermodynamically neutral H/OH exchange mechanism and not by a H atom hopping process, as generally believed. The hydrogen atoms of the H/OH pairs may be consumed in a hydroconversion reaction or desorb as H2, giving rise to /O2- pairs (where denotes an oxygen vacancy) which, in turn, may further incorporate H atoms for subsequent hydrogenations or hydrogen storage. H/OH and /O2 constitute conjugated pairs in the hydrogen spillover effect