Preparation of supported intermetallic AuCu and AuCu₃₇ nanoparticle catalyst for CO oxidation

Since Haruta demonstrated that gold nanoparticles supported on TiO₂ make an incredibly active catalyst toward low-temperature CO oxidation it has become one of the most studied reactions. Recently, it has become evident that Au-Cu alloy catalysts can enhance the catalytic activity, selectivity, and stability for an assortment of oxidative reactions. The focus of this study is to investigate the behavior of intermetallic AuCu and AuCu₃ alloys supported on SiO₂ and TiO₂ as catalysts for the CO oxidation reaction. The intermetallic catalysts were synthesized by converting supported gold nanoparticles (Au/SiO₂ or Au/TiO₂) in a Cu(C₂H₃O₂)₂ - tetraethylene glycol solution at 300 °C. Catalytic experiments show that the intermetallic phase decreases the activity for CO oxidation; however, when exposed to various oxidative pretreatment conditions it is believed that a strong Au-CuO interaction is formed that results in a more active and stable catalyst.