Current research in catalysis nanoscience at USC seeks a deeper understanding of the relationships among synthesis procedures, catalyst nanostructures, and catalyst performance (activity, selectivity, lifetime) for synergistic bimetallic and multimetallic catalysts for environmental, chemical and energy applications. Despite the substantial advances in heterogeneous catalysis over the last four decades, multimetallic catalysts (featuring active sites with at least two or more metallic elements) remain poorly understood and underutilized in practice. Nonetheless, such systems have provided examples of some of the most active and selective catalysts yet discovered. Bimetallic catalysts offer performance advantages due to "synergy": the two active metals somehow cooperate to enhance activity and/or selectivity in ways not seen in catalysts employing the individual metals. While many cases of synergy in bimetallic catalysts have been documented, we are just beginning to understand how the atomic and nanoscale structure of the bimetallic active sites results in synergistic performance.
To achieve this understanding, our team is taking a comprehensive approach. In the area of catalyst synthesis, a variety of novel preparation methods are being explored that allow for control of structural properties such as nanoparticle size, distribution, and composition. In the area of characterization, state-of-the-art spectroscopic and microscopic approaches are being pursued that allow catalysts to be “watched” under a range of conditions, including while the reaction is taking place. Extensive evaluation of catalyst performance through reaction kinetic studies in lab-scale reactors closes the experimental loop. Such studies are combined with computer simulations rooted in classical, statistical, and quantum mechanics to obtain a deeper, molecular understanding of how these catalysts function.
Our long term goal is that these efforts will generate the knowledge that will eventually allow us to design catalysts from first principles – that is, knowing the desired reaction and the possible side reactions, we will be able to design multimetallic nanoparticles with optimal activity and selectivity for the target reaction.