使用天然石墨、人造石墨、與介相碳微球製備石墨烯之比較

Comparison of Graphene Production using Natural Graphite, Artificial Graphite, and Mesophase Carbon Microbeads as Raw Materials

研究使用三種不同的石墨原料 （天然石墨、人造石墨與介相碳微球），利用化學氧化插層法分別製備氧化石墨，並進一步以高溫熱剝離／還原方式製備石墨烯。從掃描式電子顯微鏡 （SEM） 觀察到三種石墨材料經插層及熱剝離後，皆呈現出石墨層與層分離的蓬鬆結構。以穿透式電子顯微鏡 （TEM） 觀察石墨烯的表面形貌，發現三種石墨原材製備之石墨烯厚度皆相當薄，且表面皆有許多皺摺，三者的TEM 細部形貌並無明顯差異。從X 光繞射儀 （XRD） 結果可以看出，三種不同的石墨原材、及以其製備之氧化石墨及石墨烯皆呈現類似的晶體結構。同時，XRD 結果也顯示出三種石墨原材皆可達到高程度的化學插層，且三者都可以製備出剝離程度很高的少層石墨烯。從拉曼光譜可以觀察三種石墨材料及以其製備之石墨烯G-band、D-band與2D-band的特徵變化，經過化學氧化插層法與高溫熱還原處理後，均已剝離出少層數石墨烯。我們認為，未來人造石墨與介相碳微球將可取代天然石墨製備石墨烯，進而降低石墨烯製程上的成本。

Three different kinds of raw materials—natural graphite, artificialgraphite, and mesophase carbon microbeads (MCMBs) were utilized toproduce graphene. They were first converted into graphite oxide (GO) bychemical oxidation/intercalation, and then reduced/exfoliated into graphenesheets by a high-temperature treatment. Scanning electron microscope(SEM) images revealed that the final products in all three cases displayedfluffy and highly exfoliated structures. The transmission electron microscope(TEM) images showed that the three graphene samples were verythin and full of wrinkles, and there is no obvious differences between them.The three raw materials and the corresponding GO and graphene productsexhibited very similar microstructures as indicated by X-ray diffraction,which also revealed that very high degrees of intercalation and exfoliationcan be achieved for all of the three and few-layer graphene sheets can beobtained. In addition, the frequency shifts of G and 2D bands on Ramanspectra for the three samples indicated that all three graphene productswere few-layer. We believe, in the future, artificial graphite and MCMBscan replace natural graphite and minimize the material costs for grapheneproduction.