神府烟煤及其煤岩组分制备氧化石墨烯的组成、结构演变

Composition and structural evolution of graphene oxide preparedfrom Shenfu coal and its macerals

以煤为原料制备石墨烯是一种非常有前景的煤炭材料化、高值化利用途径。针对煤岩组分的组成、结构差异,探明煤岩组分在制备氧化石墨烯过程中的演变规律,是开发煤基石墨烯制备技术的理论基础。利用重选法富集低变质神府煤中镜质组和惰质组,并将富集煤岩组分通过高温石墨化得到石墨化碳,以石墨化碳为前驱体通过改良的Hummers氧化法制备煤基氧化石墨烯。利用元素分析、红外光谱、X射线衍射、拉曼光谱、扫描电镜、透射电镜以及原子力显微镜等研究煤及其煤岩组分在制备氧化石墨烯过程中的组成和结构演变规律。结果表明炭化处理使煤有机大分子结构向无定形碳结构转变,高温石墨化使煤有机大分子结构向石墨碳结构转变;惰质组呈片状结构且分子结构中芳香结构单元较多导致石墨化碳微晶尺寸较大,高温石墨化处理后其拉曼光谱的(A_(D1)/A_(G))值为0.382,镜质组高温石墨化处理后的(A_(D1)/A_(G))值为0.686,原煤高温石墨化处理后的(A_(D1)/A_(G))值为0.864;利用富惰质组得到的石墨化碳制备氧化石墨烯厚度尺寸约5 nm;而镜质组的石墨化碳中石墨微晶结构较小,得到的氧化石墨烯尺寸较小,且氧化石墨烯平均厚度超过10 nm;原煤中由于石墨化过程形成棒状结构,较难形成有序片层结构,氧化剥离也难以得到氧化石墨烯。

The preparation of graphene from coal as raw material is a very promising approach for coal material and high-value utilization.Exploring the evolution law of coal and its macerals in the preparation of graphene oxide based on their composition and structural differences is the theoretical basis for developing coal based graphene preparation technology.The vitrinite and inertite groups in Shenfu coal were enriched by gravity separation,and graphitized carbon with different coal composition was obtained by high-temperature graphitization method,and the graphitized carbon was used as the precursor through modified Hummer oxidation method to prepare coal-based graphene oxide.Elemental analysis,FT-IR,XRD,Raman spectroscopy,SEM,TEM and AFM were used to study the composition and structure evolution of Shenfu coal and its macerals,during the preparation of graphene oxide.The results show that carbonization treatment transforms the coal structure into an amorphous carbon structure,while high-temperature graphitization transforms the coal structure into a graphitized carbon structure.The rich-inertinite has a larger graphitized carbon microcrystalline structure due to the presence of layered structures with many aromatic structures units.After high-temperature graphitization treatment,for the graphitized carbon from rich-inertinite,Raman spectrum value(A_(D1)/A_(G))is 0.382,and the value(A_(D1)/A_(G))from rich-vitrinite is 0.686,and the value(A_(D1)/A_(G))is 0.864 from the raw coal.The thickness of graphene oxide from graphitized carbon obtained from rich-inertinite is approximately 5 nm.The graphitized carbon prepared from rich-vitrinite mainly presents a block structure,and the graphite microcrystalline structure is small,resulting in a smaller size of graphene oxide with a thickness of approximately 10 nm.Due to the formation of rod like structures during graphitization in raw coal,it is difficult to form an ordered lamellar structure in raw coal due to the formation of rod structure during graphitization,and it is also difficult to obtain graphene oxide by oxidative stripping.