Study On The Detection Performance Of Flame-synthesized Nano-SnO₂ Composite Material For Hydrocarbon Combustible Gas

In recent years,all kinds of hydrocarbon gas safety accidents occur frequently,so it is necessary to timely detect and monitor them to reduce related safety accidents.Metal oxide sensors are widely used because they are cheap,easy to operate and reliable.Therefore,suitable metal oxide materials can be selected to prepare sensors with excellent detection performance for hydrocarbon gas.In this paper,pure SnO₂ and composite materials based on SnO₂ were synthesized by premixed stagnation plane flame technique.The advantages of the new method and the effects of oxides and noble metals on the gas sensitive properties of SnO₂ were investigated.Firstly,in this paper,pure SnO₂ was synthesized by premixed stagnation plane flame technology and the corresponding annealing treatment was carried out.It was found that the particle size of the synthesized product was smaller than that of the conventional method,with the particle size of about 53nm and the particle size was more uniform.The maximum response value of the product to 500ppm ethylene is 5.82,which is about twice that of conventional method,and the optimal working temperature is reduced by 60℃.It can be seen that the flame method has the characteristics of simple and rapid preparation process,uniform particle size distribution and fine product.Then,the SnO₂ matrix composites mixed with In₂O₃ and Pt were synthesized by flame method.It was found that the particle size of SnO₂ decreased more under the influence of the mixture.Among these mixtures,SnO₂/12.5%In₂O₃ and SnO₂/0.396‰Pt have the best response to ethylene.Both improved,but the former improved by only 11%and the latter by 55%.At the same time,it is found in the experiment that the mixing of Pt is beneficial to reduce the working temperature,and the mixing of In₂O₃ has certain help to improve the selectivity.Finally,adding Pt to SnO₂/12.5%In₂O₃ shows that SnO₂/12.5%In₂O₃/0.066‰Pt has the best response to typical hydrocarbon gas--ethylene.Compared with pure SnO₂,SnO₂/12.5%In₂O₃ and SnO₂/0.396‰Pt synthesized by flame,it has higher response,suitable working temperature and faster response speed.It is found that the hydrocarbon gas has the best selectivity to ethylene and has a good response to hydrogen.Compared to commercial MQ type probes,the ethylene response value is higher,the response recovery speed is greatly advantageous,and the selectivity is superior.