Development Of SnO₂-based Acetylene Gas Sensor

Acetylene is widely used in daily industrial production. And it is one of thepyrolysis products of insulating oil in transformation instruments. Acetylene isdangerous in transportation, storage and industrial production because it is a kind offlammable and explosive gas with a low explosion limit（1.5%）. So the detection ofacetylene is very important. In this paper,a kind of semiconductor gas sensors fordetecting acetylene with good gas sensing properties is reported.In the first part of the paper, the fabrication and gas sensing properties ofSm-doped SnO₂nano‐particles were studied. SnO₂nano‐particles were synthesized bychemical coprecipitation. Then Sm was doped by grinding the mixtures of SnO₂andSm₂O₃. The mixtures were uesd as sensitive materials for fabricating indirect-heatinggas sensors on a ceramic tube substrate with Au electrodes on it. The result of gassensing properties investigation shows that the sensors based on the6wt%Sm-dopedSnO₂nano‐particles possessed better acetylene sensing properties than others. Thesensitivity, response and selectivity properties of the sensors are good. But therecovery time is long.In the second part of the paper, Pd/Sm-doped SnO₂nano‐particles andAu/Sm-doped SnO₂nano‐particles were fabricated by grinding the mixtures ofPdCl₂/HAuCl₄, Sm₂O₃and SnO₂nano‐particles. Then indirect-heating gas sensorswere fabricated with the similarly method. The acetylene sensing properties of thesensors were investigated. It is found that the sensing properties of the sensors basedon the Pd/Sm-doped SnO₂nano‐particles were not improved.But the sensors based onthe Au/Sm-doped SnO₂nano‐particles show better,and the4wt%Au-doped sensorspossessed best performance than others. Meanwhile, the response and recoveryproperty is better than un-doped materials. The sensors can be used for acetylene gasdetection.In the third part of the paper, Sm-doped SnO₂nano-fibers and Au/Sm-dopedSnO₂nano-fibers were successfully prepared using SnCl₂2H₂O,Sm₂O₃and HAuCl₄ as precursor with a typical electrospinning method. The two kinds of nano-fibersexhibited good sensitivity properties in500ppm acetylene. The recovery property ismuch better than the sensors based on SnO₂nano‐particles. Moreover, the two kindsof sensors possess wide detectable gas concentration ranges.In the last part of the paper, the fabrication and the simple gas sensing propertiesof hollow Au/Sm-doped SnO₂nano‐fibers were studied. The materials weresuccessfully prepared by coaxial electrospinning method. The SEM results showedthat the fibers formed tubular structures. The result of gas sensing propertiesinvestigation shows that the sensors possessed excellent acetylene sensitivityproperties, and the recovery properties is good. But the response properties should beimproved.