Fast simultaneous acquisition of low- and core-loss regions in the EELS spectrum from catalyst particles containing the heavy metals Au and Pd using the GIF Quantum system
Metals such Pd and Pt have been extensively used in the automotive industry as exhaust gas catalyst for pollution control. Until recently Au has never been used due to its thermal instability. In particular, Au particles at the nanometer scale show a melting point at relatively low temperatures that are much lower than the temperatures experienced during the catalytic process. However, Pd/Au alloys have attracted a lot of interest due to their resistance at high temperatures and this explains their use in several field such as the CO and hydrocarbon oxidation, the synthesis of vinyl acetate monomer, hydrocarbon hydrogenation and many others. Pd is the catalytic center whereas the Au has the effect of changing the chemical properties at the surface of the Pd-Au alloy. This changes influence the catalytic properties. Hence, study of the chemistry and elemental distribution is important to understand properties of the whole catalyst system. Transmission electron microscope (TEM) related techniques have proved to be valuable tools for characterizing such materials.