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Polyacrylonitrile (PAN) fiber is soft and comfortable, but its poor strength compared to other synthetic fibers has limited it wide range of applications. This study effectively improved the strength of PAN fibers by adding graphene oxide (GO) and polyvinyl alcohol (PVA) during PAN spinning. The composite fibers were prepared via gel spinning and subsequent hot drawing process. The results show that the PVA molecular chains embedded into the PAN molecular chain significantly improved the mechanical properties of the hybrid fiber. At the same time, the defect reduced the UV resistance and thermal stability of the hybrid fibers only when the PVA molecular was introduced in the PAN. Surprisingly, after the recomposition of GO in the above mixed polymer system, the interaction between the GO and matrix not only improved the mechanical properties of the fiber, but also enhanced the UV resistance and thermal stability. In addition, when the amount of GO was 0.3 wt%, the crystallinity of the GO/PVA/PAN composite fiber reached the maximum and the tensile strength was the highest. This strategic approach suggests an effective method to prepare graphene-based ternary composites fibers with high strength and novel functional characteristics. [ABSTRACT FROM AUTHOR]

Hydroxyl radicals (ṖOH) generated from a UV/O3 solution reaction is used to efficiently etch graphene oxide nanosheets under moderate conditions. Reduced holey graphene oxide is directly used as a supercapacitor electrode material and exhibits high specific capacitance (224 F g−1 at a current density of 1 A g−1) and high volumetric capacitance (up to 206 F cm−3). [ABSTRACT FROM AUTHOR]

Transition metal-doped graphene single-atom catalysts exhibit great application prospects for catalyzing hydrogen evolution applications. However, the precise timing and control of the activity of central atoms is a key problem to ensure the further development of catalysts. Revealing the correlation between the catalytic activity of the central atom and the coordination environment (atomic species, coordination number, and geometric configuration) is regarded as quite crucial for solving this key problem. Along these lines, in this work, Fe as the central atom and N, S, and P doped porous graphene (DPG) as the matrix material were used to systematically study the correlation between the coordination environment and the stability, catalytic activity of the catalyst. From the acquired results, it was demonstrated that: (1) The binding strength between the Fe atom and the N-atom DPG is the highest, and the anchoring strength of the Fe atom on two-element doping doped graphene is relatively low. Under the tetrad coordination condition, the catalyst doped with S and P atoms showed excellent performance in hydrogen evolution and water activation. A moderate correlation between the hydrogen evolution performance (ΔGH∗, E A , and ΔGOH∗) and d -band electronic properties (d -CU and d -SE) under single element doping (four and three coordination) was also detected. In addition, a certain correlation between the Fe atom outer-shell electron (3d 4s) and the hydrogen evolution performance was found. A weak correlation between the electronic properties of the double element doped graphene and the hydrogen evolution performance was also confirmed from our simulations. The results are of great significance for the regulation of the single-atom catalyst activity. [Display omitted] • The anchoring strength of the S or P doped PG to Fe atom is lower than N-doped. • The S/P doped PG with tetrad coordination showed excellent activity catalysts. • The catalytic activity showed moderate correlation with d band electronic properties. [ABSTRACT FROM AUTHOR]

• Graphene quantum dots (GQDs) were prepared by an improved AOP reaction, which shows advantages of low cost, rapid and sustainability. • The results of the radical scavenging efficiency and dye decoloration test show that GQDs exhibited high antioxidant activity. Graphene quantum dots (GQDs) are one of most promising antioxidants owing to their fascinating properties, including favorable biocompatibility, high antioxidant activity, and low toxicity. In this work, an efficient and rapid approach for preparing GQDs was developed. The graphene oxide (GO) sheet was thoroughly fragmented into the GQDs by the hydroxyl radicals (OH•) generated from a O 3 /H 2 O 2 /UV oxidation reaction. GQDs possessed a large content of sp2-hybridized carbon domains and abundant functional groups in edge. The 1,1-diphenyl-2-picryl-hydrazyl (DPPH•) radical scavenging method and dye decoloration test were used to investigate the antioxidant activity of GQDs, which exhibited high antioxidant activity and great application prospects for corrosion protection, medicinal uses, and the antioxidation of organic dyes. [ABSTRACT FROM AUTHOR]

Reduced graphene oxide/SiO2 (RGO/SiO2) serving as a novel spherical support for Ziegler-Natta (Z-N) catalyst is reported. The surface and interior of the support has a porous architecture formed by RGO/SiO2 sandwich structure. The sandwich structure is like a brick wall coated with a graphene layer of concreted as skeleton which could withstand external pressures and endow the structure with higher support stabilities. After loading the Z-N catalyst, the active components anchor on the surface and internal pores of the supports. When the ethylene molecules meet the active centers, the molecular chains grow from the surface and internal catalytic sites in a regular and well-organized way. And the process of the nascent molecular chains filled in the sandwich structure polymerization could ensure the graphene disperse uniformly in the polymer matrix. Compared with traditional methods, the porous spherical graphene support of this strategy has far more advantages and could maintain an intrinsic graphene performance in the nanocomposites. [ABSTRACT FROM AUTHOR]

Improving volumetric capacitance of supercapacitor is important and challenging for practical application. Here, porous graphene oxide (PGO) is prepared through an efficient method at room temperature after etched by Zn(CH 3 COO) 2 in several minutes. The obtained densely packed porous graphene film (PGF) was constructed by a template-assisted method. And the perforated PGF electrode material exhibits a high volumetric capacitance (C V ) of 318.8 F cm −3 in 6.0 M KOH electrolyte at the current density of 1 A g −1 . In addition, it exhibited excellent cycling stability, that is 88% retention of capacitance after 10000 charge/discharge cycles in the current density of 5 A g −1 . Furthermore, it demonstrates a capacitance of 219.0 F cm −3 (1 A g −1 ) and a cycling stability of 113% (10000 charge/discharge cycles at 5 A g −1 ) after assembled into symmetric supercapacitor. So the PGF is promising to be applied in the high performance energy storage devices with lighter quality and smaller volume. [ABSTRACT FROM AUTHOR]