ABSTRACT
Among the simplest, least expensive, and most prevalent methods to prepare supported metal catalysts begins with the process known as impregnation, whereby a high surface area oxide or carbon support is contacted with a liquid solution containing dissolved metal ions or coordination complexes such as platinum hexachloride [PtCl6]–2 (derived from chloroplatinic acid, CPA), or platinum tetraammine [(NH3)4Pt]+2 (PTA). After impregnation, wet slurries of support and metal precursor are dried and then heated in various oxidizing or reducing environments in order to remove the ligands and to reduce the metal to its active elemental state. This sequence of steps in catalyst synthesis is illustrated in Figure 13.1.
