Negative activation energies in CO oxidation over an icosahedral Au/Mg(OH)2 catalyst

In the course of our studies on CO oxidation over Au/Mg(OH)₂ we have discovered a catalyst which exhibits an apparent negative activation energy when studied under ultra‐dry conditions (80 ppb moisture content). A review of current literature suggests that the oxidation of CO may occur by a reaction between CO and OH radicals and not by oxygen as previously thought. Substantial differences in catalytic behaviour between low and high temperature suggest that the reaction is complex and that more than one reaction pathway is present. This revised version was published online in July 2006 with corrections to the Cover Date.