Encai Ou

Although energy storage devices have made great progress in recent years, their electrode materials still face some problems, such as the lack of high‐power and high rate performance in lithium battery materials, and poor energy density in capacitor materials. Here, we utilizes polyacrylonitrile (PAN) alcoholysis derivatives as a carbon source to prepare hierarchical porous carbon with a high specific surface area, and employ freeze‐expansion method to increase pore size and improve its high magnification performance. The final hierarchical porous carbon material has high specific surface area (2941 m² g⁻¹) and rich N/O doping. The porou carbon applied in supercapacitors exhibits high‐rate performance (200.5 F g⁻¹ at 100 A g⁻¹), high energy density (12.61 Wh kg⁻¹ at 150 W kg⁻¹) and excellent stability in symmetric supercapacitors. Furthermore, it owns high energy density (120.9 Wh kg⁻¹ at 160 W kg‐1) in a zinc‐ion hybrid capacitors. The excellent electrochemical performance is further demonstrated by in situ electrochemical quartz crystal microbalance and ex situ characterizations. The PAN alcoholysis and freeze‐expanded methes provides a novel strategies for the preparing of hierarchical porous carbon based on PAN, and a new insights to expand the pore size of porous carbon.

Perylene‐terminated star elastomers (PSE) containing the diblock copolymers of polystyrene (PS) and polyisoprene (PI) segments were designed and synthesized by anionic polymerization. The PSE exhibits good fluorescence performances in solution, self‐assembled aggregates, and solid state. Different supramolecular self‐assemblies in tetrahydrofuran (THF) solution based on the π−π stacking of perylene and interactions in PS can be observed from nanofibers to twisted multi‐nanoropes. Moreover, the twisted nanoropes under ultrasonic can transform spontaneously into nanorings in the stationary state, and reversibly switch between twisted nanoropes and nanorings via the manipulation of ultrasonic force. The terminating methods will offer considerable scope for the design and synthesis of new star elastomers. Meanwhile, a new insight into π−π stacking and interactions is provided for understanding multistep and cooperative self‐assembly in supramolecular self‐assembly.

Two new crystalline structures of nanoporous graphenes were synthesized via decarboxylation reaction and provided an ideal platform for oxygen evolution reaction.

Functionalized graphene was synthesized via thiol‐click reactions, and then a simple approach was adopted to immobilize Au nanoparticles (AuNPs) on the surface of functionalized graphene sheets. This approach is to use cysteamine linker with reactive amine and thiol functional groups at each end. Firstly, cysteamine hydrochloride (HS–(CH ₂ ) ₂ –NH ₂ •HCl) was incorporated onto the surface of graphene reacted with the C=C bonds by using 2,2‐azobis(2‐methylpropionitrile) (AIBN) as thermal catalyst. Then, uniform and monodispersed AuNPs were anchored on functionalized graphene surface through electrostatic interaction under acidic conditions. The obtained functionalized graphene/AuNPs composites exhibited excellent electrochemical properties investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The composites electrode exhibited high stability and good selectivity for UA and FA with the detection limit of 0.08 μM and 0.035 μM (S/N=3), respectively. Our work provides a simple, convenient and green route to synthesize functional graphene which is potentially useful in electroanalysis.

3D graphene frameworks/Co₃O₄ composites are produced by the thermal explosion method, in which the generation of Co₃O₄ nanoparticles, reduction of graphene oxide, and creation of 3D frameworks are simultaneously completed. The process prevents the agglomeration of Co₃O₄ particles effectively, resulting in monodispersed Co₃O₄ nanoparticles scattered on the 3D graphene frameworks evenly. The prepared 3D graphene frameworks/Co₃O₄ composites used as electrodes for supercapacitor display a definite improvement on electrochemical performance with high specific capacitance (≈1765 F g⁻¹ at a current density of 1 A g⁻¹), good rate performance (≈1266 F g⁻¹ at a current density of 20 A g⁻¹), and excellent stability (≈93% maintenance of specific capacitance at a constant current density of 10 A g⁻¹ after 5000 cycles). In addition, the composites are also employed as nonenzymatic sensors for the electrochemical detection of glucose, which exhibit high sensitivity (122.16 µA mM ⁻¹ cm⁻²) and noteworthy lower detection limit (157 × 10⁻⁹ M, S/N = 3). Therefore, the authors expect that the 3D graphene frameworks/Co₃O₄ composites described here would possess potential applications as the electrode materials in supercapacitors and nonenzymatic detection of glucose.

The use of 5-guanosine monophosphate (GMP) with Sr²⁺ ions to form G-quadruplex bundles as supramolecular templates for the preparation of hierarchical mesoporous silica nanotube materials is reported here, and some mesopores with a diameter of 4–22 nm were obtained. Furthermore, some mesopore channels which run perpendicularly to the center axis of the tube and penetrate right through the outer wall of the nanotubes were achieved by removing the templates. Besides, porous hollow silica spheres were obtained by changing some of the reaction conditions during the process of preparation. Their structures are stable even after high temperature calcination. A formation mechanism was proposed and discussed, and their structures were characterized using a number of means including X-ray diffraction, IR spectra, N₂ adsorption–desorption isotherms, scanning electron microscopy (SEM) and transmission electron microscopy (TEM).