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The preparation of three-dimensional honeycomb nitrogen-doped carbon materials (3D-HNCMs) which can be used as electrode materials for supercapacitors is reported. The composites with the 3D honeycomb structure exhibited better electrochemical performance, and the structure and properties were proved by various means, such as SEM, TEM, IR, N2 sorption, XRD and XPS. Used as electrode materials for supercapacitors in the KOH electrolyte, 3D-HNCMs displayed a significantly high specific capacitance (409 F/g at a current of 0.5 A/g). Moreover, the 3D-HNCM electrode exhibited superior electrochemical performance, such as excellent cycling stability (98% capacitance retention after 10,000 cycles), a maximum energy density of 15.37 W h/kg, a maximum power density of 40.3 kW/kg, and low equivalent series resistance (2.1 Ω). Particularly, the electrochemical characteristic of 3D-HNCMs could be attributed to the synergistic effect of a high surface area, unique microporous and mesoporous structure, and nitrogen atom doping. These carbon materials with unique structure are promising electrode materials for future supercapacitor application.

A surfactant-assisted hydrothermal route was developed for the synthesis of three-dimensional (3D) flower-like TiO2 microsphere decorated graphene composite (FT/GN) based on the hydrothermal reduction of graphene oxide and formation of TiO2 microsphere in the presence of poly(vinyl pyrrolidone) (PVP). By several characterization methods such as X-ray diffraction, scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy, we demonstrated that uniform flower-like TiO2 (FT) microsphere with average diameter of 1.4 μm have successfully anchored on the surface of graphene sheets. Effects of PVP and reaction temperature on the microstructure of the composite were investigated. Benefits from the combined graphene with FT microsphere were that the FT/GN composite exhibited higher adsorption capacity and photocatalytic activity for the removal of rhodamin B (RhB) than blank FT microsphere and P25. Especially, the removal rate of RhB using FT/8GN composite under UV light irradiation reached 99.2% in 80 min, with corresponding TOC removal efficiency of 66.49%. Moreover, the recycled photoactivity tests showed that the prepared composite were stable enough and maintained high removal efficiency for RhB even after four cycles. It is expected that the present synthetic strategy may provide a new strategy for the fabrication of various GN-based hybrids with multi-dimensional structure.

A facile and scalable method is used in this study for oxidation polymerization and catalytic carbonization method to prepare three-dimensional hierarchically structured nitrogen-doped carbon nanohybrids (3D N-CNs) which could be used as the efficient electrode material for supercapacitors. In the synthesis process, citric acid plays an important role in controlling the shape of nitrogen-doped carbon nanohybrids. As an electrode material for supercapacitors, the 3D N-CNs-2 possess high specific capacitance of 274.6 F g−1 at 0.5 A g−1, excellent rate capability (ca.75.5 % retention along with the current density increasing from 0.5 to 20 A g−1) in 6 M KOH aqueous solution. The electrochemical performance can be ascribed to the synergistic effects of the hierarchical nanostructure and nitrogen doping, suggesting that the 3D N-CNs-2 as novel electrode materials may have the potential applications in high-performance energy storage devices.

A fast electrochemical chiral sensor based on L-lysine (L-Lys) covalent functionalize reduced graphene oxide (RGO) has been developed for electrochemical recognize of tryptophan (Trp) enantiomers. The reduced graphene oxide/L-Lys (RGO/L-Lys) chiral composites with excellent water-soluble and biocompatible is very suitable for electrochemical sensor. Meanwhile, the L-Lys retains original chirality in RGO/L-Lys composites, which progress to electrochemical chiral sensor. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) were implemented to monitor the electrochemical behavior when RGO/L-Lys simply modified on glassy carbon electrode (RGO/L-Lys/GCE). Surprisingly, the reduction of peak current was significantly different after the RGO/L-Lys composites interacted with L-Trp or D-Trp, and the testing time is very short. It suggested that the RGO/L-Lys/GCE can be used as an electrochemical chiral sensor for the discrimination of Trp enantiomers. In this electrochemical discrimination process, the three-point interaction between L-Lys and Trp enantiomers has played an important role. Further research indicated that the decreased of peak currents versus percentage of L-Trp of Trp racemic mixture exhibits a fine linear relationship, it provides opportunity to make analysis for discrimination of Trp enantiomers. The RGO/L-Lys/GCE electrochemical chiral sensor with rapid recognition, good sensitivity and high stability provided an efficient method to recognize and determine Trp enantiomers.

Calliandra like rutile TiO2 hierarchical microspheres with different diameters were successfully prepared by hydrothermal method via altering reaction time. All these as synthesized unique hierarchical microspheres displayed higher UV shielding capability compared with commercial P25 and anatase TiO2. Noticeably, the UV shielding efficiency of these microspheres had a close relation to their diameters and packing density of constituted nanorods. The S-24h-C sample exhibited the highest UV shielding efficiency, which could not only block all UV light below 400 nm but also show poor photocatalytic activity under UV light radiation, indicating its great applied potential in UV-blocking materials.

Polyethyleneimine-reduced graphene oxide (PEI-RGO) nanocomposites were synthesized via the nucleophilic substitution reactions between the active amine groups in PEI and the surface-exposed epoxy groups in graphene oxide. The nanocomposites combining with nafion were used as the sensing material for the analysis of trace amount of Cu2+ in solution using differential pulse anodic stripping voltammetry (DPASV) and showed specific electrochemical properties. Various experimental parameters that exert influence on deposition and stripping of metal ions, such as pH values, deposition potential, and deposition time, were optimized. Under the optimized parameters, the stripping peaks response increased linearly with increasing concentration of Cu2+ in the ranges of 1 to 70 μmol/L, which was the general feature of the DPASV method for the application of trace metal ion sensing. The limit of detection (S/N = 3) was estimated to be 0.3 μmol/L for Cu2+ and the sensitivity was down to 0.5274 μA/(μmol/L). More importantly, selective detection toward trace Cu2+ was achieved in the presence of other coexisting interfering metal ions.

An electrochemical chiral sensor based on reduced graphene oxide (RGO) non-covalently functionalized with 1,10-phenanthroline copper(II) (PhenCu) complex has been developed for electrochemical discrimination of tryptophan (Trp) enantiomers. The formation and morphology of reduced graphene oxide/1,10-phenanthroline copper(II) (RGO/PhenCu) composites were confirmed by Fourier-transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). Cyclic voltammetry (CV) was employed to monitor the electrochemical behavior of RGO/PhenCu immobilized on glassy carbon electrode (RGO/PhenCu/GCE). The reduction in peak current was significantly different when the chiral sensor interacted with L-Trp and D-Trp. This suggested that RGO/PhenCu/GCE could be used as an electrochemical chiral sensor for the discrimination of Trp enantiomers. Further studies showed that the peak current decreased linearly along with an increasing percentage of L-Trp in the Trp mixture. The RGO/PhenCu/GCE electrochemical chiral sensor, with rapid recognition, good sensitivity and high stability, provided an efficient method to recognize and discriminate Trp enantiomers.

Silvetia babingtonii is a potentially economic brown alga for sources of food and high-value added utilization. So far, sporeling nursery and field cultivation has not been successful. The lack of knowledge on development and life cycle of this alga hinder the development of techniques for the sporeings and cultivation. In this study, internal structure of oogonium and antherium of S. babingtonii was observed with hematoxylin and eosin staining and through microscope. Meanwhile, early development from zygotes to juvenile sporelings was studied at 20 degrees C under 60-100 mu mol photons m(-2) s(-1). Zygotes germinated and divided into thallus and rhizoid cells. The larger thallus cells further divided and developed into juvenile sporelings; while the smaller rhizoid cells divided and elongated into rhizoid hairs. These findings documented the life cycle of S. babingtonii and provided fundamental knowledge for sporeling nursery in the near future.

Grateloupia turuturu Yamada is an economically valuable red alga with great potential in nutraceuticals and pharmaceuticals. Filaments of G. turuturu are of primary importance in germplasm preservation and sporeling culture, although filaments were not present in its life cycle. In this study, effects of temperature (10, 15, 20, 25, and 30 °C) and irradiance (10, 30, 60, and 90 μmol photons m−2 s−1) with photoperiod 10:14 h (light/dark) on filament development were investigated. Our results indicated that 25 °C was the optimal temperature for the formation of discoid crusts regardless of the irradiance. Conditions of 20 °C and 60 μmol photons m−2 s−1 promoted the development of discoid crusts and formation of upright thalli.

Flg22, which is the most conserved 22-amino acid peptide in the N-terminal part of flagellin, functions as an effective elicitor in higher plants. Marine algae and higher plants share some conserved characteristics on defense response pathways. Flg22-induced defense responses were investigated in female gametophytes of Saccharina japonica. Condensation of chloroplasts and thickened cell walls, as well as relatively stable structures of mitochondria and nucleus indicated that there were hypersensitive programmed cell death occurred after induction by flg22. By using luminol-dependent luminescence detection method, rapid release of H2O2 was detected in the induced female gametophytes and reached a peak concentration of about 46 μM at 2 h. Reactive oxygen species production was also observed histologically using the fluorescent dye 2′,7′-dichlorofluorescein diacetate, showing a consistent result with quantitative analysis of H2O2. Furthermore, results of antioxidant enzyme activities indicated that there was a trend in the order of catalase > superoxide dismutase > glutathione peroxidase. Finally, high level phenol content of cell-free extracts was found after flg22 induction. According to our results, flg22 could be an effective elicitor which could induce defense responses in female gametophytes of S. japonica.

Grateloupia turuturu is a commercial red alga with potential value in nutraceuticals and pharmaceuticals. To supplement information on its life history and verify whether carpospores can be used for seedling culture, early development of G. turuturu was investigated under culture conditions (27°C, 10–13 μol/(m2·s) in irradiance, photoperiod 10:14 h L:D). Three physiological stages were recognized by continuous microscopic observation: division stage, discoid crust stage, and juvenile seedling stage. At the beginning of the division stage, the carpospores developed germ tubes into which the carpospore protoplasm was evacuated, and then the carpospore protoplasm in the germ tubes began to divide continuously until discoid crusts formed. Finally, upright thalli appeared on the discoid crusts and developed into juvenile seedlings. It took about 60 days for carpospores to develop into juvenile seedlings. The growth parameters, including germination rate for carpospores and discoid crust diameter, were recorded. These results contribute more information on the life cycle, and at the same time are of great significance in the scaling-up of artificial seedling cultures of G. turuturu.