Study On Detection Characteristics Of Metallic Nickel Doped Tin Oxide Gas Sensor

Sensor technology is the key technologies to be solved for online monitoring ofdissolved gas in transformer oil. Tin oxide （SnO₂） is an important semiconductor gassensitive material which can use metal oxides doped method to improve its poorsensitivity, limited selectivity, long response-recovery time and weak repeatability,therefore, metal oxide doped SnO₂is expected to be well applied in the on-linemonitoring of dissolved gas in transformer oil. Owing to lack of the gas sensing andsimulation mechanism, the current exploring of new sensing material is mainly based onexperimental studies via a trial-and-error design fashion. This paper researched Nidoped SnO₂gas sensors from theory and experiment, providing a new idea for thefurther development of SnO₂gas sensors.The structure of relaxation SnO₂（110） surface, Ni doped SnO₂（110） surface, Nidoped reduced SnO₂（110） surface, Ni doped reduced SnO₂（110） surface adsorping H₂and their microcosmic electronic structure information are analyzed by first-principlesthat are based on density functional theory via Materials Studio Castep softwarepackage. The results showed that Ni atom tend to replace six coordination Sn6cintoSnO₂crystal cell; The bridge oxygen O₂cthat is coordination with Ni is more like toreduce；The adsorption site increase after Ni doping though comparing the dopantformation energy and bond length of different hydrogen adsorption model；Adsorptionof hydrogen are in the form of dissociation on SnO₂（110） surface and then generatedihydrogen complexes （waterlike） overflowing SnO₂（110）surface，Thereby Ni doping ishelpful to improve the sensitivity of the sensor.Undoped and5%Ni doped SnO₂nano powder materials were prepared byhydrothermal method and characterized by XRD and SEM, It can be found that Nidoping can prevent particles of SnO₂growing up. Two powders grain size with gooddispersibility, particle ball, is approximately10.62nm and7.44nm respectively, It’sindicated that the prepared powders with full developed particles are right rutilenanometer SnO₂powder materials. powder materials assembled into SnO₂gas sensorsare qualified to test the response characteristics for gas dissolved in transformer oil （H₂,CO, CH₄, C₂H₆, C₂H₄, C₂H₂）.Study on the detection characteristics of two sensors base on gas sensorstesting platform in lab.Test results show that the Ni doping can observably develop the sensitivity,response and recovery time and repeatability of hydrogen and methane.butlimited improving the selectivity. Our simulation results are consistency with ourexperimental results.