2.2 Supported materials for the hydrogenation of dienes in heterogeneous system

In terms of reactivity, heterogeneous catalysts are usually less reactive than homogeneous systems. However, heterogeneous catalysts only require simple separation processes for purification and can be more easily recycled compared to homogeneous catalysts. Therefore, many research groups have been working on advancing fundamental understanding on the structure/property relationship and technological applications of heterogeneous catalysts in the past decade. Many of these supported metal catalysts are in fact in nanoscale dimensions, but many earlier catalysis studies did not attempt detailed characterizations on material sizes and their distributions on the supports. Both materials with and without welldefined sizes and structures including the catalysts reported as nanoparticulate materials are discussed here as traditional catalysts.
