Preparation And VOCs Sensing Properties Of RGO-MO_x Composite Nanofibers

With the rapid development of social and industrial production,the types and numbers of poisonous and harmful gases are increasing.The development of gas sensors is accompanied with the increasingly critical phenomenon of environmental pollution.Metal oxide semiconductor gas sensor has the advantages of low production cost,small size and easy preparation of gas sensitive materials.It is widely used in gas detection.However,poor selectivity and high working temperature limit its further development.Graphene,because of its large specific surface area and fast electron transfer rate,has been widely used in sensor research.In this paper,a few reduced graphene oxide?rGO?and metal oxide semiconductor materials such as SnO₂ and TiO₂ were used to improve the gas sensing properties of oxide semiconductor materials.The metal oxide semiconductor nanofibers were prepared by electrospinning,and the surface of metal oxide semiconductor nanofibers were modified by rGO through a two-step hydrothermal method,or adding graphene oxide?GO?directly in the preparation of metal oxide semiconductor nanofibers spinning process,with the subsequent calcination to synthesis rGO / MOx composite nanofibers gas sensing materials.The effects of rGO addition and adding methods on the gas sensing properties of rGO-oxide semiconductor composite nanofibers were systematically investigated.The main contents are as follows:1.The TiO₂ nanofibers were prepared by electrospinning.The preparation of rGO/TiO₂ composite nanofibers by electrospinning was carried out by adding rGO to the electrospinning precursor solution.The effects of rGO complex on the morphology of TiO₂ nanofibers and the gas-sensing properties of VOCs were discussed.The results showed that the compound of rGO did not have a great effect on the morphology and crystal structure of the material,and improved the sensitivity of the material to VOCs.At 250 ?,the sensitivity of rGO/TiO₂ composites to200 ppm ethanol gas is 43.24,which is 22.8 times of that of TiO₂,and its response time is also lower than that of TiO₂ nanofibers.2.The TiO₂ nanofibers were prepared by electrospinning.The surface modification of TiO₂ nanofibers by rGO was carried out a two-step hydrothermal method to prepare rGO surface modified TiO₂ nanofibers.The results showed that rGO made the surface morphology of TiO₂ more rough,but did not affect the crystal structure of TiO₂ material.The gas sensing results show that rGO surface modified TiO₂ nanofibers further enhance the sensitivity of the material and shorten the response and recovery time.3.The rGO/SnO₂ composite nanofibers were prepared by electrospinning,and the rGO surface modified SnO₂ nanofibers were prepared by a two-step hydrothermal method to study the effect of rGO on the VOCs sensing properties of other n-type metal oxide semiconductors.The results of gas-sensing tests show that the promotion to SnO₂ gas sensing properties of rGO complex and surface modification is more obvious.At 150 ?,the sensitivity of rGO surface modified SnO₂ nanofibers to 100 ppm ethanol is 287,and comparing with SnO₂ nanofibers,the recovery time is relatively shortened.