PREPARATION AND CHARACTERIZATION OF PT AL2O3 AEROSOL PRECURSORS AS MODEL PT-EMISSIONS FROM CATALYTIC-CONVERTERS/

A model catalyst to simulate inorganic emissions from automotive catal yst was developed to study the toxicological potential of platinum par ticles. A 3-5% system Pt/Al2O3 was selected in order to achieve suffic ient analytical sensitivity in later toxicological studies. A genuine support material (alumina), which was used in industrial automotive ca talyst production, was impregnated, calcined and activated. The prepar ation procedure was optimised in a series of experiments in order to f ulfil the special conditions imposed by the toxicology testing program . As the toxicological investigations represent a separate program, th ese experiments will not be discussed here but in separate work to be published by the co-authors. Sample were characterised by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), X-ray-phot oelectron spectroscopy (XPS) and X-ray fluorescence analysis (XRFA). F urthermore, the thermal effects during activation were studied by diff erential scanning calorimetry (DSC) and by thermogravimetry/differenti al thermoanalysis (TG/DTA). The catalytic activity of the sample was t ested using a CO oscillation as model reaction, investigated by ion-mo lecule mass spectrometry (IMR-MS). All experimental results, including the catalytic activity, prove the authenticity of the sample as a rea l automobile catalyst. (C) 1997 Elsevier Science B.V.