The Preparation Of Partially Hydrogenated Graphene And The Preparation Of Graphene With Electrochemically-liquid Phase Exfoliation Method

Graphene, with its unique two-dimensional structure and excellent electronicproperties, is considered to be a promising material as an alternative to silicon.However, the applications of graphene in many semiconductor transistors have beenhampered by its inherent zero band gap; Moreover, the preparation of graphene oftenintroduce oxygenous functional groups, undermining the crystal structure andelectronic properties of graphene. Faced with these problems, we aim to open a bandgap on graphene and improve the preparation method of graphene.Firstly，Hydrogenation was used as an elegant way to introduce a band gap intographene. We demonstrate a new route-borane hydrogenation method on thepreparation of partially hydrogenated graphene. A novel reduction method withborane was successfully used in the hydrogenation of graphene for the first time, andopened a band gap on graphene with a value of1.8eV. Through a series ofexperiments, we determine that the optimal reaction conditions:5°C, the time underhydrogenation and hydrolysis is three hours, respectively. This route does not requireheating, with mild reaction conditions and simple operation, and only two steps-hydrogenation and hydrolysis were required on the way to hydrogenated graphene;Reduced graphene oxide was used as raw material, which is easy to manufacture andmeet the requirement of the industrial production. Through infrared spectroscopy(FTIR), raman spectroscopy (Raman), scanning electron microscopy (SEM),transmission electron microscopy (TEM), electron energy loss spectroscopy (EELS)and thermal gravimetric analysis (TGA) and so on, we determine the presence ofpartially hydrogenated graphene and the weight content of hydrogen in graphene bothin qualitative way and the quantitative one. The ultraviolet spectrum (UV-Vis) datademonstrated that hydrogenated graphene has a band gap which is close to that of thesemiconductor silicon. A narrow band gap of partially hydrogenatedgraphene(semiconductor), maybe have a more widespread application in the industryof the electronic device.As to the preparation of graphene, we firstly adopted the method ofelectrochemically-liquid phase exfoliation. After conventional electrochemicalexfoliation, we carried out second exfoliation in the solvent of N-methyl-2-pyrrolidone(NMP), which cost only two hours than previous1~462hours.The combination of the electrochemical exfoliation and liquid phase exfoliationshorten the reaction time by centrifugation/ultrasonic. Through a series ofcharacterization, such as infrared spectroscopy (FTIR), Raman spectroscopy (Raman),transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS)and atomic force (AFM), we determine the thickness and composition of graphene.Characterization results indicate that this method can produce the single layer and fewlayers graphene.