Preparation And Gas Sensing Performances Of Graphene/g-C₃N₄-Metal Qxide Composites

Two-dimensional nanosheet materials have some unique nanostructures,whose electron conduction and heat transfer are confined in one flat,thus exhibiting some distinctive characteristics.It was found that with the number of layers of two-dimensional materials decreased the characteristics of two-dimensional nanosheet materials changed of,including semiconductors,insulators,metallicity,low-temperature superconductivity and so on.In this paper,the gas-sensitive properties were studied by combining graphene or graphene-like g-C₃N₄ with spinel materials?ZnGa₂O₄,MgGa₂O₄?.G-MgGa₂O₄,g-C₃N₄-ZnGa₂O₄,and g-C₃N₄-MgGa₂O₄ composites were prepared by hydrothermal method.The materials were characterized by XRD,SEM,TEM,HRTEM,TG-DSC,FT-IR,Raman,UV-Vis,XPS and N₂ absorption-desorption,and gas sensing properties of different materials were tested.The experimental results showed that the sensitivity of g-C₃N₄-ZnGa₂O₄?ZGO-2?composite to 100ppm TMA at room temperature reached 7.9,which was 6 times compared with pure ZnGa₂O₄ gas sensor,and its response and recovery times were about 21 s.The sensitivity of the gas sensing materials to ammonia,ethanol and other gases was less than 1.2,The detection line wasdown to 0.01 ppm;At room temperature,the sensitivity of g-C₃N₄-MgGa₂O₄?MGO-10%?composite to 100 ppm TMA was about 31,and the detection limitation was 0.1 ppb,the sensitivity was 1.6.The response and recovery times of MGO-10%material to 100ppm TMA was about14 s and 9 s respectively,and the sensitivity to 100ppm ethanol,acetic acid,acetaldehyde,etc.was less than 2.4.The gas sensing properties of composites obtained by adding different graphenes were studied.At room temperature,the response of G-MgGa₂O₄?MGO-0.1wt%?composites was about 266 to 100ppm acetic acid,and the response and recovery time were about 50 s and 35 s,respectively.The lowest detectable concentration of acetic acid was 1 ppb,and the sensitivity was 1.3.