Studies On Modification Of H₂S Gas Sensor Material Based On SnO₂

This paper reviews the history and the development of the method for determining the concentration of the gas of hydrogen sulfide and the development of gas sensor and the current states of hydrogen sulfide gas sensor. We select the sol-gel method to prepare sintered tin dioxide gas sensor and thin film tin dioxide gas sensor. We also modify the sol-gel method to make the process simpler and get more stable sol. We find, though this method, a kind of tin dioxide gas sensor doped with copper performs well in the relative low temperature. In our experiment, we use the "cold atom mercury meter" to determine the concentration of hydrogen sulfide gas indirectly. Using this method, we can face the difficulty of controlling the concentration of hydrogen sulfide gas in a way. With the image analysis, XRD, AFM, we study the surface modality, the crystal of the particles and the elements of the sensors. We find the thin film sensor has a network surface and the copper dose not form the copper dioxide and other phase with tin dioxide. We also use a voltage meter made by our laboratory, which can be connected to PC and record the voltage continuously. Then influence on the sensor resistance of water vapor and ammonia can be ignored when the operation temperature is above a certain value. We set up a process for studying the hydrogen sulfide gas sensor, which is simple and fit for our laboratory. Finally we try to get a sensing film with the method of self-assembly using polyelectrolyte (FDDA). We find, using the polyelectrolyte, self-assembly is a kind of practical and easy to control method for forming a film. The future prospects in research and development of hydrogen sulfide gas sensor based on semiconductor is given in the end.