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Lithium–sulfur batteries (LSB) show excellent potential as future energy storage devices with high energy density, but their slow redox kinetics and the shuttle effect seriously hinder their commercial application. Herein, a 0D@2D composite was obtained by anchoring polar nano-TiO2 onto a 2D layered g-C3N4 surface in situ, and a functional separator was prepared using multi-walled carbon nanotubes as a conductive substrate. Due to their long-range conductivity, multi-walled carbon nanotubes make up for the low conductivity of TiO2@g-C3N4 to some extent. A lithium–sulfur battery prepared with a modified separator exhibited excellent long-term cycle performance, a good lithium ion diffusion rate, and rapid redox kinetics. The initial specific discharge capacity of the composite was 1316 mAh g−1 at 1 C, and a high specific discharge capacity of 569.9 mAh g−1 was maintained after 800 cycles (the capacity decay rate per cycle was only 0.07%). Even at the high current density of 5 C, a specific capacity of 784 mAh g−1 was achieved. After 60 cycles at 0.5 C, the modified separator retained the discharge capacity of 718 mAh g−1 under a sulfur load of 2.58 mg cm−2. In summary, the construction of a heterojunction significantly improved the overall cycle stability of the battery and the utilization rate of active substances. Therefore, this study provides a simple and effective strategy for further improving the overall performance and commercial application of lithium–sulfur batteries. [ABSTRACT FROM AUTHOR]

The heterojunction structure of semiconductor photocatalysts is significant for making full use of their capabilities for organic molecules and dye degradation. In this paper, we present a heterogeneous junction composite fabricated with hybrid phase TiO2 and g-C3N4 for methylene blue (MB) removal through adsorption and photocatalytic degradation. The heterogeneous junction system was prepared by hydrothermal treatment with a subsequent pyrolysis process. The variation of the proportion and lattice structure of hybrid phase TiO2 in the synthesized catalysts was analyzed by refinement. Adsorption experiments showed that the maximum adsorption capacity of TiO2/g-C3N4 (1 : 10) was 1667 mg g−1, which was 45.97 times and 63.78 times higher than that of TiO2 and g-C3N4, respectively. In the photodegradation process, the TiO2/g-C3N4 (1 : 10) photocatalyst shows a removal rate of MB of 100 mg L−1, which was as high as 96.262%, significantly higher than that of pure TiO2 and g-C3N4. Brunner–Emmett–Teller (BET) measurements and Fourier transform infrared spectroscopy (FTIR) showed that the adsorption of MB onto TiO2/g-C3N4(1 : 10) was chemical adsorption, and ˙OH, which acts as an active substance, was found to play a major role in the photocatalytic degradation process. Overall, the developed hybrid phase TiO2/g-C3N4 heterojunction composite may be beneficial for the treatment of water pollution. [ABSTRACT FROM AUTHOR]

Lithium‐sulfur batteries are one of the most promising energy storage devices in the future due to their high specific capacity and abundant natural reserves. However, the shuttle effect of soluble intermediate polysulfide products can lead to rapid decay of battery capacity, short cycle life and serious self‐discharge effect, which hinders the development of lithium‐sulfur batteries. Here, we coated the separator with a mixed SeS2/KB coating, which can effectively stop the polysulfide shuttle and improve the performance of lithium‐sulfur batteries through the physical barrier of KB and the strong adsorption of SeS2 in synergy with each other. Theoretical calculations and experiments show that SeS2 has a strong adsorption effect on polysulfides. The lithium‐sulfur battery equipped with SeS2/KB separator has excellent electrochemical performance, maintaining a capacity of 482 mAh gS−1after 1000 cycles at 1 C current density, with a decay rate of only 0.047 % per cycle. [ABSTRACT FROM AUTHOR]

Lithium-sulfur batteries exhibit great potential as one of the most promising energy storage devices due to their high theoretical energy density and specific capacity. However, the shuttle effect of the soluble polysulfide intermediates could lead to a severe self-discharge effect that hinders the development of lithium-sulfur batteries. In this paper, a battery separator has been prepared based on NiFe2O4/Ketjen Black (KB) modification by a simple method to solve the shuttle effect and improve the battery performance. The as-modified separator with the combination of small-size KB and NiFe2O4 nanoparticles can effectively use the physical and chemical double-layer adsorption to prevent polysulfide from the shuttle. Moreover, it can give full play to its catalytic effect to improve the conversion efficiency of polysulfide and activate the dead sulfur. The results show that the NiFe2O4/KB-modified separator battery still maintains a discharge capacity of 406.27 mAh/g after 1000 stable cycles at a high current density of 1 C. Furthermore, the coulombic efficiency remains at 99%, and the average capacity attenuation per cycle is only 0.051%. This simple and effective method can significantly improve the application capacity of lithium-sulfur batteries. [ABSTRACT FROM AUTHOR]

Electrolytic water splitting with evolution of both hydrogen (HER) and oxygen (OER) is an attractive way to produce clean energy hydrogen. It is critical to explore effective, but low-cost electrocatalysts for the evolution of oxygen (OER) owing to its sluggish kinetics for practical applications. Fe-based catalysts have advantages over Ni- and Co-based materials because of low costs, abundance of raw materials, and environmental issues. However, their inefficiency as OER catalysts has caused them to receive little attention. Herein, the FeS 2 /C catalyst with porous nanostructure was synthesized with rational design via the in situ electrochemical activation method, which serves as a good catalytic reaction in the OER process. The FeS 2 /C catalyst delivers overpotential values of only 291 mV and 338 mV current densities of 10 mA/cm 2 and 50 mA/cm 2 , respectively, after electrochemical activation, and exhibits staying power for 15 h.

To investigate the effect of three kinds of polymeric scaffolds on attachment, proliferation and differentiation of bone marrow mesenchymal stem cells, the cells were different polymeric scaffolds of PLA-PEG, PLA, PLGA, respectively. The proliferation of cell was evaluated by cell count; the attachment and morphology of BMSCs were observed by SEM; and differentiation was detected by alkaline phosphatase activity, fluorescence, and RT-PCR methods. Results showed that the cells in PLGA group spread better among BMSCs adhered to the three polymeric scaffolds. The activity of ALP was detected after 3 days culture in these three groups. There were no significant differences between PLA-PEG and PLGA groups, but the activity of ALP was higher than PLA group. The gene expressions of osteocalicin and collagen I were also observed in the early culture time. Calcium nodes formation in these polymeric scaffolds were detected. BMSC spreading first, then overlapping growth and secretion of matrix around the bottom and surface of scaffolds were observed through SEM. In summary, PLA-PEG and PLGA are better polymeric scaffolds for the bone tissue engineering, compared with PLA.