Winning Combination of Cu and Fe Oxide Clusters with an Alumina Support for Low-Temperature Catalytic Oxidation of Volatile Organic Compounds

A gamma-aluminasupport functionalized with transition metalsis one of the most widely used industrial catalysts for the totaloxidation of volatile organic compounds (VOCs) as air pollutants athigher temperatures (280-450 degrees C). By rational design ofa bimetal CuFe-gamma-alumina catalyst, synthesized from a dawsonitealumina precursor, the activity in total oxidation of toluene as amodel VOC at a lower temperature (200-380 degrees C) is achieved.A fundamental understanding of the catalyst and the reaction mechanismis elucidated by advanced microscopic and spectroscopic characterizationsas well as by temperature-programmed surface techniques. The natureof the metal-support bonding and the optimal abundance betweenCu-O-Al and Fe-O-Al species in the catalystsleads to synergistic catalytic activity promoted by small amountsof iron (Fe/Al = 0.005). The change in the metal oxide-clusteralumina interface is related to the nature of the surfaces to whichthe Cu atoms attach. In the most active catalyst, the CuO6 octahedra are attached to 4 Al atoms, while in the less active catalyst,they are attached to only 3 Al atoms. The oxidation of toluene occursvia the Langmuir-Hinshelwood mechanism. The presented materialintroduces a prospective family of low-cost and scalable oxidationcatalysts with superior efficiency at lower temperatures.