Influence of the ternary alloy formation on the catalytic activity of metallic nano-layers and the mechanism of chemical sensor reactions I

The catalytic activity of ternary alloys (Pd/Pt/Ni, Pd/Pt/Ag, Pd/Pt/Au, Pd/Pt/Ru and Pd/Pt/Fe) is to be examined using samples with a continuous gradients in concentration of all three components on a semiconductor chip. By means of a laser scanning method the local sensor characteristics of thin layer structures are determined. As result of the area scans all possible compositions of the ternary alloys are characterized in their reactivity. As an examples of the catalytic reaction the signals of chemical semiconductor sensors for hydrogen, hydrogen fluoride and oxygen were selected. Significant influences are expected on the sensitivity, selectivity and the dynamic sensor behavior. The well-known prevention of the catalyst poisoning by CO, due to binary alloys, is to be optimized by the ternary alloys. In addition to the semiconductor measuring techniques EDX, IR spectroscopy, XPS and the impedance spectroscopy are used for the investigation of the mechanisms of the catalyzed sensor reactions at the alloys. The experimental strategy represents a new method in combinatorial chemistry and High Throughput Screening in the basic research. The results of the project should be of interest not only for chemical sensor technology but also for the heterogeneous catalysis.