Research On The Gas-sensitive Performances Of Co₃O₄ And Its Composited Metal Oxides To Volatile Organic Compounds

After seafood products dead,they release a volatile triethylamine(TEA)gas,which seems as a toxic and harmful gas can cause adverse reactions for the eyes,respiratory tract and lungs for humans,and is also used as an evaluation indicator for judging the freshness of seafood.For this reason,it becomes urgent to design a gas-sensitive sensor capable of detecting triethylamine gas in a rapid and timely manner.The structure of nanosheets self-assembled hollow Co₃O₄ micro-tubes are designed to increase the reactive sites on the surface of the material and to provide more adsorption-desorption channels for rapid detection of TEA gas.The composited CuO/Co₃O₄ gas sensor is further constructed to strengthen the gas-sensitive response of TEA gas by using the driving effect of the in-built electric field in the homojunction to induce the production with more carriers on the material surface.What's more,UV light-excitation is used to improve the TEA gas sensing properties of composited metal oxide gas-sensing materials by providing with more carriers through the effective separation of photogenerated electron-hole pairs in the composited metal oxide gas-sensing materials.The contents for this topic are as follows:(1)A strategy was reported to synthesis of hollow Co₃O₄ microtubes assembled by vertically aligned nanosheets via sacrificial template of MgO combined with the following thermal annealing(200??250?and 300?).It shows that the largest specific surface area,richest oxygen vacancies,and suitable pore size of Co₃O₄-200,which enhances the reactive sites and gas transport capacity of the material to some extent.The gas-sensitive performance of the Co₃O₄-200 sample towards 200 ppm TEA reached 220%at 180? with response and recovery times of 13s and 81s,respectively,which also demonstrated excellent selectivity and stability.(2)On the basis of the synthesis of nanosheets self-assembled Co₃O₄ micro-tubes,the CuO nanosheets were loaded on the surface of Co₃O₄ micro-tubes in a cross-embedded manner to form a composited CuO/Co₃O₄ gas-sensitive material(Cu-Co-1?Cu-Co-2 and Cu-Co-3)by water-bath method,which further enhances the reactive sites of the material and adjusts the material's ability to adsorb TEA gas.The gas-sensitive performance of Cu-Co-2 towards 200 ppm TEA gas at 320? reached 7.6,which is 2.37 times better than the gas-sensitive performance of pure Co₃O₄ material,which also has good selectivity and stability.Under the effect of UV light-excitation to enhance the gas-sensitive sensing properties of composite materials,The photoexcitation Cu-Co-2 composite gas sensing material achieved a gas sensing performance of 8.3 towards 200 ppm TEA gas at 320?.