In this presentation, I will discuss the design of nano-composite catalysts by utilizing interfacial interactions of two different kinds of materials to generate strong synergistic effects. The design principle will be illustrated with transition metal-ceria metal oxide composites for oxidative destruction of environmental pollutants. The strong synergism is demonstrated for oxidation of CO, hydrocarbons, and soot. In particular, the latest progress for low-temperature reduction of NO will be reported.