Functionalization Of Graphene Aerogels And Its Applications

Graphene has received increasing attention due to its uniqe structure and outstanding performance.The three-dimensional graphene with high porosity and low density,have a great application in many areas such as energy,environment,catalysis and biological medical.In this paper,the method of reducted the graphite oxide as the most effective and economical method is chosen to obtain graphene.This method includes the following steps: ultrasonic,hydrothermal reduction self-assembly and freeze drying.On the basis of this method,the functional graphene aerogels were preparated by covalent modification and co-doping,then the graphene aerogels are used in the field of heavy metals adsorption and lithium ion battery.The structure and properties of the materials were characterized by SEM,TEM,TG,XRD and so on.The main results are as follows:1?Graphene aerogels are obtained by the modified Hummers method.The preparation of graphene aerogels includes: ultrasonic dispersion,and self-assembling into graphene-based aerogel by hydrothermal reduction.The influences of concentration,pH value and drying methods on preparation process were investigated.It is found that the concentration can change the pore size of aerogel effectively,the pH value make a little influence on the preparation process,and drying method of graphene aerogels play a critical role in maintaining the internal pore structure,and freeze drying can presrerve the original structure,with the volume shrinkage is only 5%.2?The functional graphene aerogels are prepared by covalent modification with EDTA-Silane and they can adsorb Pb2 + in solutions effectively.It is found that the absorption capacity of functional graphene aerogel can reach the maximum--205mg/g with the pH 6.8,temperature of 30 ?,adsorption time of 60 min,and initial concentration of 100 mg/L.3?The MnO₂ are prepared using KMnO₄ as manganese source.MnCO3/GGA is prepared by hydrothermal treatment.Then it used as anode material in lithium-ion battery.Compared with GGA,MnCO3/GGA shows an extraordinarily electrochemical performance and exhibits a specific capacity of 986.5 mAh/g at 0.1 A/g current density after 50 cycles as an anode material for lithium-ion batteries.MnCO3/GGA also shows good rate performance and the specific capacity can maintain 1201mAg/h at the current density of 0.1A/g after cycling at different current density.Above all,the functionalized graphene aerogels can be obtained through simple and green modifications,and show excellent performance in the filed of environmental protection and energy.