| In order to increase the gas sensitive property of WO3 nano-material,shape controling?precious metals doping and rGO doping were tried tobe used.WO3 nano-belts?WO3 nano-plate?urchinlike WO3 were synthesized,and Au-doped WO3?Ag-doped WO3 and rGO-doped WO3 were also made to further increase the sensitive property of WO3 nano-material.This paper also disgused the impression to the products'perfomes by changing the experimental conditions,what's more,the gas sensing mechanism was also introdused.The main dimension can be summarized as follows:?1?Firstly,SEM?TEM and XRD test were carried out to characterize the crystal,structure and morphology.And then,H2S?CO?NO?NH3?HCHO and some other kinds of gas were used to test the sensitive property of the products,analysised what from the fields of gas sensitivity,response-recovery speed,gas selectivity and stability.The results showed that,those three products have great selectivity to H2S,and also have nice stability,which can show a stable gas sensitive property in auite a long time.The response-recovery speed of WO3 nano-plate is the fastest in those three products,the response time is 11s and the recovery time is 9s.The Hex urchinlike WO3,which has more complex morphological and structrue which extent that WO3 has a bigger specific surface area,so it's gas selectivity is better than those tow kinds products,the response sensitivity is 118 with the best response temperature of 240?to 500ppm H2S.?2?Au and Ag doped complex morphology WO3 products were prepared in this reserch,a variety of methods were used to characterize the crystal morphology of those products,after what,some tests were carried out to detect thiers gas sensitive property.Comparising the gas sensing properties of those products with different Au or Ag doping concentrations to find out the best doping scale.The products are Au-doped and Ag-doped Hex WO3,product with Au dopting scale wt.=1.0%shows a nice sensitivity to H2S,whose sensitivity is 132 with the best response temperature of 240?to 400ppm H2S,and the Ag-doped product is urchinlike WO3,the best doping scale is 0.8%,the best sensing temperature is 180?which is lower than undoped WO3,Those tow kinds of products show nice selectivity to H2S,and also behaved well in stability test in 60 days.?3?rGO-doped WO3 is also made,the GO is made by Hammers method,and than rGO-doped WO3 with different doping scale were synthesised by hydrothermal method,which is formed by rGO?WO3 plate and particles.By Comparing the sensing property of the products with different rGO doping scale,when rGO doping scale wt.=0.8%,the product shows the best sensitivity,which is 95 at 180?to 200ppm H2S,the response and recovery time are both less than 50s,and this product also perfomed well in selectivity test and stability test. |
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