| Acetone is a typical reducing gas.It is flammable and explosive,so it has potential industrial hazards.Long-term exposure can cause health hazards such as acute poisoning or chronic diseases.However,it can also be used as one of the indicators for diabetes detection.Therefore,acetone gas monitoring is of great significance to human health.Sm Fe O3 belongs to a kind of perovskite oxide,which has the advantages of high thermal stability and high catalytic activity.As a P-type semiconductor,Sm Fe O3 has a high response value and good selectivity to oxidizing gases（such as O3,NO2,VOC）,while there are few studies on the reducing gas acetone,and there is a disadvantage of low response value and high working temperature,therefore,it is necessary to further optimize the gas sensing properties of Sm Fe O3 nanomaterials to meet practical application requirements.In this paper,Ti O2/Sm Fe O3 composites,Sm1-xPrxFe O3 nanoparticles,Sm0.95Pr0.05Fe1-xCoxO3 nanoparticles were prepared by sol-gel method,and using XRD,SEM,BET and other characterization methods to analyze the structure,morphology and specific surface area of the material,.the effects of compounding,A-site and B-site doping methods on the gas-sensing properties of Sm Fe O3 oxide to acetone were explored,the optimal doping and compounding ratios were explored,and the gas-sensing reaction mechanism was analyzed.The main conclusions are as follows:（1）（x）Ti O2/（1-x）Sm Fe O3（x=0,1/5,1/4,1/3 and 1/2）nanoparticles were prepared by sol-gel method.The response value of the gas sensor to 200 ppm acetone gas shows a"mountain peak"trend with the change of x value at their respective optimal operating temperatures,the x=1/4 sensor has the highest response value peak,and the response value to acetone gas reaches 37 at the optimal working temperature of 280°C,and has good selectivity and stability.However,the x=1/2 sensor with the most Ti O2 complex has a lower response to acetone than the pure Sm Fe O3 sensor,which may be due to the serious agglomeration of the sample and the inhibition effect of too much Ti O2.（2）Sm1-xPrxFe O3（x=0,0.01,0.05 and 0.1）nanoparticles were prepared by sol-gel method.Among the Sm Fe O3,Sm0.99Pr0.01Fe O3,Sm0.95Pr0.05Fe O3 and Sm0.9Pr0.1Fe O3 sensors,the Sm0.95Pr0.05Fe O3 nanoparticles effectively increase the gas response of the Sm Fe O3 sensor due to its largest specific surface area and smaller particle size value,achieving a response value of 36.9 at 280°C for 100 ppm acetone.In addition,it not only has high responsiveness,but also has relatively fast response and recovery ability,and its stability is also good,showing better selectivity for acetone gas due to its small pore size.（3）In order to further improve the acetone gas-sensing performance of Sm0.95Pr0.05Fe O3sensor,Sm0.95Pr0.05Fe1-xCoxO3（x=0,0.01,0.03 and 0.05）nanoparticles were prepared by sol-gel method.The results of the gas sensing performance test show that the gas sensing element prepared by Co doping reduces the working temperature,the optimal doping ratio is3%,and the best response to 100 ppm acetone gas is 22.4 at the optimal operating temperature of 260°C.However,the overall response of the sensors to acetone gas after Co doping is lower than that of the Sm0.95Pr0.05Fe O3 sensor,indicating that Co doping has an inhibitory effect on the acetone gas-sensing performance of the Sm0.95Pr0.05Fe O3 sensor. |
