Lithium sulfur (Li-S) batteries possess high theoretical specific capacity (1675 mAh g−1) and energy density (2567 Wh kg−1), but are plagued by their poor rate performance. The discovery of new carbon sources, design of novel porous carbon structures, and effective hetero-atom doping of the sulfur matrix are key to overcome this dilemma. In this paper, a boron-doped porous carbon material with a termite nest shape (TNPBC) was obtained from a new carbon source, polyaspartic acid, and borax. Importantly, the doping, activation, and pyrolysis were integrated into one step through a low cost and simple methodology. The borax was essential to formation of a high surface porous architecture and provided boron dopants, which, combined with polyaspartic acid, achieves co-doping (B and N) carbon materials with special porous structures. The simultaneous pore-formation and doping leave an abundance of hetero-atoms exposed on the surface of pores, which enhances the electrostatic interactions between the hetero-atoms and the charged species in the batteries. As a result, the S/TNPBC cathode maintains a stable capacity of 703 mAh g−1 with an excellent Coulombic efficiency of 101.3% after 120 cycles at 0.1C. Moreover, it exhibits an excellent rate capability with an initial capacity of 650 mAh g−1 at 0.5C and sustains a capacity of 500 mAh g−1 after 100 cycles. Furthermore, when TNPBC is used as the anode in a sodium ion battery, an excellent rate capability is achieved. The specific charge capacity is three times greater than without boron doping at 500 mA g−1. Due to the simple fabrication process and desirable properties of this novel architecture, TNPBC provides a new strategy for enhancing the performance of commercial energy storage devices.A novel kind of porous boron-doped carbon (TNPBC) with a termite nest structure was synthesized by combining doping, activation, and pyrolysis into one step. Using the synthesized material as a sulfur reservoir, TNPBC effectively relieved the “shuttle effect” commonly found in Li-S electrodes and achieved a decent rate performance in Li-S and sodium ion batteries.Download high-res image (181KB)Download full-size image

•Highly dispersed quaternized graphenes (QGs) were prepared.•Quaternized graphenes (QGs) reinforced polysulfone composite anion exchange membranes were fabricated.•QPSU−0.5%-QGs showed a 4-fold improvement in the bicarbonate conductivity than that of QPSU at 80 °C.•Our strategy opens up a new perspective in the preparation of novel composite anion exchange membranes for AMFC.A series of novel composite anion exchange membranes for alkaline fuel cell were prepared by incorporating quaternized graphenes (QGs) into the chloromethylated polysulfone (CMPSU), and followed by quaternization and alkalization. The highly exfoliated quaternized graphenes (QGs) were obtained by epoxide ring opening reaction of APTES-functionalized graphenes (A-FGs) with glycidyltrimethylammonium chloride (GDTMAC). The influence of the content of QGs on the properties of the obtained composite membranes was studied. The results indicated that the QPSU−0.5%-QGs showed a 4-fold improvement in the bicarbonate conductivity than that of pristine QPSU membrane at 80 °C, and the QPSU−0.25%-QGs showed a 3-fold increase in Young׳s modules and tensile strength. The performance improvement of the membranes could be attributed to the formation of the interconnected transfer channels provided by the QGs and the excellent compatibility between QPSU and QGs. In addition, the good morphologies without phase separation, acceptable thermal properties, alkaline resistances and oxide stabilities, low water uptakes and swelling ratios were also presented in the composite membranes. Our study demonstrated that the incorporation of proper content of QGs into the polymer matrix to fabricate the composite membranes is a facile way to improve the properties of the anion fuel cell membranes, especially in the anion conductivity and mechanical property.

•A novel PPV@MSN@CdTe nanoprobe for Cu2+ was fabricated via electrostatic interaction.•The nanoprobe exhibited the dual fluorescent emission of red-light from CdTe QDs and green-light of PPV.•The probe can selectively detect Cu2+ via FRET, while the green-emission of PPV remains.•The nanoprobe can efficaciously distinguish Cu2+ from other interfering mental ions, especially Hg2+.•The nanoprobe provided an efficient platform for the sensing of Cu2+ with a detection limit of 31.2 nM.This paper reported a facile method for fabricating CdTe quantum dots decorated fluorescent mesoporous silica nanoparticles containing poly(p-phenylenevinylene) by electrostatic interaction in aqueous solution. The resulted fluorescent hybrid nanomaterials showed the dual-emission centered at 500 nm and 717 nm, which can be used as a fluorescent probe to detect Cu2+ in water through fluorescence resonance energy transfer. Cu2+ can be captured by the amino groups of the polyethyleneimine to form an absorbent complex, resulting in a strong quenching of red-emission from CdTe quantum dots on the surface of nanoparticles via energy transfer. However, the green-emission of poly(p-phenylenevinylene) remained. Therefore the addition of Cu2+ induced the fluorescent evolution of the nanoprobe from red to green. The nanoprobe provided an efficient platform for the sensing of Cu2+ with a detection limit of 31.2 nM. Compared with pure quantum dots, the nanoprobe can distinguish Cu2+ from Hg2+.A facile strategy for fabricating CdTe QDs decorated fluorescent mesoporous silica nanoparticles containing poly(p-phenylenevinylene) by electrostatic interaction in aqueous solution has been reported. This hybrid nanomaterial can be used as a fluorescent probe to detect Cu2+ through fluorescence resonance energy transfer. The resulted nanoprobe can distinguish Cu2+ from other interfering mental ions efficaciously. The nanoprobe provided an efficient platform for the sensing of Cu2+ with a detection limit of 31.2 nM.

•Per-6-NH2-β-CD was functionalized with fluorescein 5(6)-isothiocyanate.•The PL quenching of FITC-(NH2)-CD is sensitive to the content of TNT due to FRET.•The PL sensor allows a quantitative detection TNT with a detection limit of 20 nM.•Our strategy opens up a new perspective in the design of sensor for various analytes.A new fluorescent sensor based on single water-soluble β-cyclodextrin (β-CD) molecule as the support carrier of donor and acceptor complex was designed, and used for TNT detection by fluorescence resonance energy transfer (FRET). In this sensing platform, per-6-amino-β-CD (per-6-NH2-β-CD) was used as the detection vehicle. The probe dye of fluorescein 5(6)-isothiocyanate (FITC) was covalently linked onto the per-6-NH2-β-CD rim with the grafting molar ratio of 1:1, the residual amino groups of per-6-NH2-β-CD can adsorb TNT molecules by forming Meisenheimer complex (TNT–amine complex) with TNT. The absorbtion spectrum of this complex has a spectral overlapping with the emission of FITC in aqueous solution, so it can strongly suppress the fluorescence emission of the adjacent FITC through FRET on β-CD vehicle. This FRET-based fluorescent sensing technique provides a facile, ultrasensitive and selective detection method for TNT molecule. The observed linear fluorescence intensity change could allow the quantitative detection TNT with the detection limit of 20 nM in water.

Carbon quantum dots (CQDs) were demonstrated to have the ability to enhance the photocatalytic performance of monoclinic BiVO4 with different exposed facets under visible light.

Cd1−xZnxSe1−ySy alloyed NCs were functionalized with 8-hydroxyquinoline and its derivatives by a ligand exchange process. The efficient white light emitting NCs can be obtained by adjusting the ratio of blue-light ligand (ND) to NCs. The charge transfer process was observed in the functionalized NCs systems.

Carbon quantum dots (CQDs) were demonstrated to have the ability to enhance the photocatalytic performance of monoclinic BiVO4 with different exposed facets under visible light.