Avoiding Self‐Poisoning: A Key Feature for the High Activity of Au/Mg(OH) 2 Catalysts in Continuous Low‐Temperature CO Oxidation

Au/Mg(OH) 2 catalysts have been reported to be far more active in the catalytic low‐temperature CO oxidation (below 0 °C) than the thoroughly investigated Au/TiO 2 catalysts. Based on kinetic and in situ infrared spectroscopy (DRIFTS) measurements, we demonstrate that the comparatively weak interaction of Au/Mg(OH) 2 with CO 2 formed during the low‐temperature reaction is the main reason for the superior catalyst performance. This feature enables rapid product desorption and hence continuous CO oxidation at temperatures well below 0 °C. At these temperatures, Au/TiO 2 also catalyzes CO 2 formation, but does not allow for CO 2 desorption, which results in self‐poisoning. At higher temperatures (above 0 °C), however, CO 2 formation is rate‐limiting, which results in a much higher activity for Au/TiO 2 under these reaction conditions.