Nanocrystal catalysis is emerging as a new research direction in our group. The objective of this project is to design and process novel catalysts based on binary nanoparticle assemblies and characterize their performance in heterogeneous chemical reactions. The proposed research is inspired by recent concurrent advances in the directed assembly and processing of nanoparticles into superstructures. Access to size and shape-specific particles and precise control over their assembly into secondary structures presents exciting opportunities to arrange nanoparticle in ways in which they can synergistically interact to enhance catalytic activity while at the same time limiting migration and sintering to prevent deactivation. The proposed research is organized in a framework that integrates processing, characterization, and performance. The innovative character of the proposed work derives from the use of non-equilibrium processing methods to create stable and catalytically active structures that have not been accessible via conventional methods. We seek to gain detailed insights into the primary and secondary structure of the binary assembly and to correlate the structure to catalytic performance and stability. We will apply this approach to two model systems: (i) the water-gas shift reaction on Au/Fe2O3 assemblies and (ii) the oxygen reduction reaction in Pd/Pt nanoparticle assemblies. We see the versatility of this approach as a key strength and anticipate that insights gained from the proposed study will likely spur additional advances that may lead to new paradigms in NP catalyst design.