Immobilized bimetallic clusters: sensors and catalysts of new generation

   Nanocrystalline materials based on tin dioxide chemically modified catalytic clusters obtained in the form of powders , thin films, using a set of synthetic methods in a wide range of compositions with a crystallite size controlled in a range of 3-50 nm. Synthesis of nanocrystalline powders held SnO₂ a- gel deposition of tin acid followed by heat treatment . Clusters from metals Fe, Co, Ni, Pd, Au, Ru , and Cu and bimetallic clusters based on Au-Ni, Au-Fe and Au-Co. Values ​​with different metals applied to the surface of the pre -synthesized nanocrystalline SnO₂ by impregnation and anion adsorption. Thin films of 0.8 mm thickness of tin dioxide , chemically modified bimetallic clusters Pd-Cu were prepared by spray pyrolysis of organic compounds on insulator substrates. The systematic study of the influence of the catalyst clusters on the electrical properties of powders and films by measuring the dc conductivity and impedance spectroscopy in a wide temperature range. The contribution of ionic and electronic conductivity, surface area and volume of the crystallites depends on the nature of catalityc clusters. All measurements were performed in a controlled atmosphere.
    The effect of bimetallic clusters on sensory properties of the modified stannic oxide upon detecting trace amounts of toxic gases NO₂, CO, H₂S, NH₃, acetone and ethanol in air. It has been shown that the catalytic clusters increases the sensor signal magnitude and reduce an operating temperature of the semiconductor sensor. Found a synergistic effect due to the mutual influence of Au and Ni clusters on the sensitivity of the material to NO₂. The optimum compositions of sensor materials for the detection of NO₂ and CO at the maximum permissible concentration (MPC working area). The result of the application for the invention "Method of preparation material gas sensor based on tin dioxide".