Controlled nanoparticle preparation using the synthetic tools of nanotechnology will have substantial impacts on catalysis research. Among these impacts is the potential to controllably tune the activity and selectivity of one metal by incorporating heteroatoms, particularly dopant metals. Our work is aimed at developing the tools to synthesize well-defined bimetallic nanoparticles, deposit them onto oxide supports and prepare active model catalysts. In particular this paper presents recent results using PAMAM dendrimers to template supported Au catalysts. Low temperature (263-293 K) CO oxidation studies show the templated catalysts to be as or more active than traditionally prepared materials. Additionally, oxygen saturation kinetics and analysis shed light onto the mechanisms at work in this reaction and provided a kinetic characterization of the active site(s). Affects of incorporating heterometals (Ni, Cu, Co) in the Au nanoparticle synthesis will also be presented, particularly their impact on CO oxidation activity and mechanism.