Preparation And Gas Sensing Properties Of Multilevel Interconnected Porous SnO₂ Gas-sensing Materials

Tin oxide?SnO₂?nanomaterials has received considerable attention for its distinctive and promising applications incatalysis,photoelecrric and gas sensors due to its high electrical,optical,magnetic and catalyst properties.In this paper,monodisperse polystyrene?PS?microspheres as a template were synthesized via emulsion polymerization route.The SnO₂ nanocrystals as a precursor were synthesized through a hydro-thermal route.The relationship between the porous structure and sensing properties were also studied.The results are as follows:1.SnO₂ nanocrystals with average size of 3.2 nm and high purity were synthesized through a hydro-thermal route.PS microspheres at the micro and sub-micro scale were synthesized via emulsion polymerization route.The standard deviation of particle size is smaller than 5%.2.The multilevel interconnected porous SnO₂ nanomaterials was prepared by template method with SnO₂ nanoparticles as a precursor and PS microspheres as a template.Moreover,the influence of the precursor,filling process,the volume ratio of PS/SnO₂ nanocrystals,concentration of PS microspheres,the self-assembled temperature,and calcination temperature on the three-dimensional 3DOM structure were investigated.The study shows that: the most suitable volume ratio range of PS microspheres and SnO₂ nanocrystals is 70:30 and 80:20;the order of macropores was improved by increasing the concentration of PS microspheres;the most suitable self-assembled temperature is 70 ?;the most suitable calcination temperature is 400?.3.The gas-sensing properties of multilevel interconnected porous SnO₂ was investigated.The gas-sensing properties of highly ordered interconnected macroporous SnO₂ with different pore size were also investigated.The results shows that calcination temperature plays an important role on the the gas-sensing properties of 3DOM SnO₂ is superior than the multilevel interconnected porous SnO₂.Moreover,the report shows that the gas-sensing properties increase with the increase of the macropore size.