Preparation and characterisation of Pt/Al2O3 aerosol precursors as model Pt-emissions from catalytic converters

A model catalyst to simulate inorganic emissions from automotive catalyst was developed to study the toxicological potential of platinum particles. A 3-5% system Pt/Al2O3 was selected in order to achieve sufficient analytical sensitivity in later toxicological studies. A genuine support material (alumina), which was used in industrial automotive catalyst production, was impregnated, calcined and activated. The preparation procedure was optimised in a series of experiments in order to fulfil the special conditions imposed by the toxicology testing program. As the toxicological investigations represent a separate program, these 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-photoelectron spectroscopy (XPS) and X-ray fluorescence analysis (XRFA). Furthermore, the thermal effects during activation were studied by differential scanning calorimetry (DSC) and by thermogravimetry/differential thermoanalysis (TG/DTA). The catalytic activity of the sample was tested using a CO oscillation as model reaction, investigated by ion-molecule mass spectrometry (IMR-MS). All experimental results, including the catalytic activity, prove the authenticity of the sample as a real automobile catalyst. (C) 1997 Elsevier Science B.V.