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As a kind of cheap and easily available organic molecular with Faradic redox activity, quinones can well combined with carbon-materials by non-covalent π–π conjugation and remedy its shortcomings possessing relatively low specific capacitance. However, in previous studies, the combination of quinones and carbon-based materials often requires toxic organic solvent or high energy-consuming and interminable process, greatly hindering their practical application. Here we use water-soluble sodium anthraquinone-2-sulfonate (AQS) and graphene oxide (GO) solution as raw materials to directly obtain AQS composite reduced GO (AQS/rGO) hydrogels by chemical reduction, the whole process of which is performed at relatively low temperature and normal pressure, and only takes a short time, resulting in great promotion in sustainability and efficiency. The AQS/rGO hydrogel exhibiting a high specific capacitance of 387.43 F g−1 at 1 A g−1 and an excellent cycling stability of 91.11% after 10000 cycles at 10 A g−1, has a prodigious improvement for the pure graphene in all aspects. Besides, the maximum energy density of the asymmetric supercapacitor assembled by AQS/rGO-1 hydrogel reaches 15.98 W h kg−1 at the power density of 325.02 W kg−1. This work provide a new idea for the green and efficient preparation of graphene organic quinones composite and has an important significance for its practical application. • AQS can be combined with graphene sheet by non-covalent π-π conjugation. • The process of preparing AQS/rGO hydrogels is utrla-simple, green and efficient. • The AQS/rGO hydrogels exhibits superior electrochemical performance to pure graphene. • The asymmetric supercapacitor delivers high energy density. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) nanomaterials have become a new class of microwave absorption (MA) materials due to their high specific surface area and peculiar electronic properties. In this study, MoS 2 /graphene 2D hybrid nanosheets with isomorphic hetero-structures are prepared by liquid exfoliation and hydrothermal reaction. Their chemical composition and morphology are characterized and their MA properties are also investigated comprehensively. The minimum reflection loss (RL) value of an absorber containing wax and 20 wt% MoS 2 /graphene hybrid nanosheets (MoS 2 /GN) is −55.3 dB at a thickness of only 1.6 mm. The largest effective absorption bandwidth is up to 5.6 GHz for an absorber containing wax and 15 wt% MoS 2 /GN at a thickness of 2.2 mm. The enhanced MA performance of MoS 2 /GN is attributed to the high electrical conductivity of graphene and the multiple MoS 2 /graphene interfaces in the heterogeneous structures. The results suggest that those light-weight MoS 2 /graphene hybrid nanosheets are very promising materials for electromagnetic wave absorbing, which can exhibit broad effective absorption bandwidth in the absorber containing low loadings of MA materials at a small thickness. Besides, the facile preparation of MoS 2 /graphene hybrid nanosheets reported in this work provides a feasible and effective approach in the synthesis of high-performance 2D MA nanomaterials. [ABSTRACT FROM AUTHOR]