Preparation Of 3D Graphene Foam And Application

This article system has prepared the pure graphene foam（GF）, graphene @ nickel foam composite（rGO/NF）, graphene @ manganese dioxide @ nickel foam composite（rGO/MnO₂/NF） and characterization of the morphology, structure, basic performance, at the same time, application the graphene foam in NO₂ detection and super capacitor.Firstly, pure graphene foam prepared by self-assembly method, in view of the reduction degree of graphene foam were discussed in this paper. The results showed that with hydroiodic acid and ascorbic acid at the same time as additives for the first time, then carried on the second reduction with hydrazine hydrate. The high reduction degree of GF was prepared in this way. Afterwards, the morphology and structure of GF are investigated intensively by a variety of means such as scanning electron microscopy（SEM）, X-ray diffraction（XRD）, Raman spectroscopy, Fourier transform infrared spectroscopy（FT-IR）. The results show that GF has a three-dimensional porous structure, the average aperture to three microns, structure characterization to prove the success prepared of GF. Following the conductivity properties, mechanical properties, hydrophobicity and density of GF was studed. The results showed that: the highest conductivity of GF is 0.91 S/cm, the compressive strength is 0.1 MPa when recovery strain is 80%, the contact angle is 127.23°, the density is 1.8×10-3 g/cm3 which light enough to be on the dandelion and not crushed. The GF for detecting of NO₂ which concentration is 50 ppm detection sensitivity is 0.85% and the detection limit concentration is 24 ppm at room temperature.Using graphene oxide solution and nickel foam as raw materials by self-assembly mean to get rGO/NF and studied the graphene oxide concentration and drying methods as influence factors. The morphology and structure of rGO/NF are investigated by SEM, XRD, as well FT-IR. The result proved that the graphene with nickel foam can effectively composited. Then analysed the electrical conductivity and hydrophobic of the rGO/NF. Research has shown that graphene after load with nickel foam dramatically improved its mechanical strength and electrical conductivity. The electrical conductivity of rGO/NF can reach 688.11 S/cm. The excellent electrochemical performance was achieved of composite foam which concentration of graphene oxide is 1 mg/cm3 and get compound foam in hot dry way, including a high specific capacitance of 454 F/g at the current density of 5 A/g and a high capacitance retention efficiency of 86% after 500 times charging/discharging cycles.In order to further improve the application property of graphene foam, proceeds to rGO/NF as a template with hydrothermal process to get r GO/MnO₂/NF. Afterwards, the morphology and structure of composite are investigated by SEM, XRD and FT-IR. The results proved that the manganese dioxide with porous lamellar structure effective carrying on the template. Then analysed the electrical conductivity and hydrophobic of the composite foam. Study have shown that the conductivity of the composite foam can reach 519.92 S/cm, contact Angle decreased to 93.59 °, at the same time, the compound foam application in gas detection and super capacitor. The application performance of composite determined the best preparation technology. The resulting rGO/MnO₂/NF for detecting NO₂ which concentration is 50 ppm detection sensitivity is 1.51% and the detection limit concentration is 17 ppm at room temperature. The application of the composite foam to supercapacitor, the excellent electrochemical performance was achieved, including a high specific capacitance of 510 F/g at the current density of 3 A/g and a high capacitance retention efficiency of 96% after 500 times charging/discharging cycles.