The Research On Preparation And Gas Sensitivity Of SnO₂ /gold Composite Materials

Metal Oxides (MO_X) have being drawn more and more attentions as gas sensing materials. Various strategies, such as doping, material nanosizing and incorporation of noble metals particles into metal oxide gas sensing materials, have been adopted to improve their sensitivity.In this work, Au nanostructures and SnO₂ nano-crystals have been prepared by chemical method. The effect of preparation conditions on the morphology of Au nanostructures have been investigated. The TEM results show that, the morphology of Au nanostructures were decided by the molar ratio of the HAuCl₄ and K₂C₂O₄. With the decreasing of the ratio, the morphology of products gradually evolutes to spider-web-like architectures from nanoparticles.SnO₂/Au composite material has been synthesized through chemical interaction between Au nanostructures and SnO₂ nano-crystals. PH value is the decisive factor for its synthesis. The XRD results indicates that, SnO₂/Au compisite material can formate under acidic conditions.Gas-sensitive performances of the prepared composite material have been investigated. The dependence of gas-sensitivity on gas concentration and operating temperature has been studied. Compared to SnO₂ sensor, the sensitivity of composite material is improved, it elevates along with the gas concentration increasing. Moreover, the optimal response temperature for CH₃CH₂OH fall to 300℃from 350℃.