(472c) Facile Novel Synthesis and Characterization of Gold-Copper Bimetallic Nanoclusters for Applications in Oxidation Catalysis

Catalysis through active transition metal nanoparticles often allows high reactivity or selectivity in low temperatures. Varying metal selection and amounts in bimetallic nanoclusters offer a new route to tune activity, selectivity, among other optical and structural properties. This work represents a facile approach to the synthesis of gold-copper bimetallic nanoparticles and the properties they exude from this synthesis method. In this synthesis, triphenylphosphine is used as the bulky capping agent to prevent agglomeration and sodium borohydride is used as the reducing agent. HAADF-STEM confirms the average size of the nanoclusters at approximately 2 nm. UV-Vis and fluorescence measurements were also conducted to measure the optical properties of these clusters. DRIFTS studies show the triphenylphosphine ligand interaction varies with the composition of bimetallic clusters. The particles are dispersed onto (<67 um) TiO₂, MgO, and SiO₂ among other metal oxides as a support structures. These supported metal cluster materials were then subsequently used as catalysts for CO oxidation and benzyl alcohol oxidation to determine structure-function relationships relating the composition in the form of the Au:Cu ratio of the catalyst to its activity. These results help to guide future applications and design of engineered materials in oxidation catalysis.