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Abstract Sandwich-like ZIF-8 nanocrystal derived N-doped carbon decorated graphene sheets are developed through in-situ growth and followed by a thermal annealing treatment. The sandwich-like N-doped carbon decorated graphene sheets (NCGs) contain graphene substrate and the carbon nanoparticles with 30–50 nm in size. The sandwich-like NCGs generate a large specific surface area of 816.4 m2 g−1. With the high surface area and nitrogen doping, the as-fabricated NCGs as electrode materials for supercapacitor exhibit high specific capacitance of 225.0 F g−1 at 0.5 A g−1, an enhanced rate capability and excellent electrochemical stability with 96.8% retention after 10000 cycles even at 10 A g−1. The symmetry supercapacitor based on NCGs delivers an energy density of 12.7 Wh kg−1 at a specific power of 447 W kg−1. When the power density increases to 15126 W kg−1, the energy density can still keep 6.5 W h kg−1. Furthermore, the symmetry supercapacitor shows an excellent cycle stability with 96.6% capacitance retention at 2 A g−1 after 10000 cycles. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

Highlights: [•] Co3O4 nanocrystals with size of 20nm homogeneously embedded in the carbon matrix are successfully synthesized. [•] Cycle exceeds 400 times in half cells at a 5C (5 Ag−1) rate while retaining about 1000 mAhg−1 reversible capacities. [•] Large rates up to 10C for are achieved with high energy density. [•] Such Co3O4 exhibits excellent high-rate capability and cycling stability. [Copyright &y& Elsevier]

A solid electrolyte interphase (SEI)‐free surface and fully reversible conversion are simultaneously realized in the Li‐ion storage of a specially designed ZnO porous nanocomposite with in situ surfaces/interfaces organic encapsulation for the first time. The built‐in oxygen‐ and/or moisture‐isolating organic layer of subangstrom thickness not only avoids the SEI formation, but also guarantees monodisperse and ultrasmall dimensions of ZnO nanocrystals, which are crucial for the high initial Coulombic efficiency (ICE) and fully reversible conversion. Benefiting from the high ICE up to 91.4%, stable long‐term cyclibility (95% capacity retention at 1 A g−1 after 1400 cycles), and no sacrificing Li‐ion storage capability (868 mAh g−1 at 0.1 A g−1), the ZnO nanocomposite demonstrates the highest initial Li‐ion utilization efficiency (ILUE, ≈85.4%) among previous transition metal oxide–based full cells. [ABSTRACT FROM AUTHOR]

Copper(I) oxide (Cu2O) is an attractive photocatalyst because of its abundance, low toxicity, environmental compatibility, and narrow direct band gap, which allows efficient light harvesting. However, Cu2O exhibits poor photocatalytic performance and photostability because of its short electron diffusion length and low hole mobility. Here, it is demonstrated that nanodiamond (ND) can greatly improve the photocatalytic hydrogen evolution reaction (HER) of the p-type photocatalyst Cu2O nanocrystals by nanocomposition. Compared with pure Cu2O nanocrystals, this composite shows a tremendous improvement in HER performance and photostability. HER rates of 100.0 mg NDs-Cu2O nanocrystals are 1597 and 824 under the simulated solar light irradiation (AM 1.5, 100 mW cm−2) and visible light irradiation (420-760 nm, 77.5 mW cm−2), respectively. The solar-to-hydrogen conversion efficiency of this composite is 0.85%, which is nearly ten times higher than that of pure Cu2O. The quantum efficiency of the composite is high, with values of 0.17% at and 0.23% at . The broad spectral response of ND provides numerous carriers for the subsequent reactions. The electron-donating ability of ND and suitable band structures of the two components promote electron injection from ND to Cu2O. These results suggest the broad applicability of ND to ameliorate the photoelectric properties of semiconductors. [ABSTRACT FROM AUTHOR]

Abstract: A facile way towards high rate and long lifespan anode materials based on SnO2 and commercial multiwalled carbon nanotubes (MWCNTs) is readily achieved through a combination of activation and hydrothermal treatment. The former endows the MWCNTs with abundant hydrophilic radicals, while the latter guarantees intimate connection between SnO2 and MWCNTs; eventually, monodisperse SnO2 nanocrystals ca. 3nm are firmly anchored on the MWCNTs without agglomeration. When used for lithium ion batteries (LIBs) anodes, the hybrid composite exhibits excellent cycling capability with high reversible capacity about 700 mAh g−1 (based on total weight of the composite) for 150 cycles at 0.1 A g−1 superior to both components involved. Besides large rates of 5 A g−1 with recoverable initial reversible capacity, it also last for more than 1000 cycles with little capacity decay, outperforming most SnO2 based carbon nanotubes composites (SnO2/CNTs) so far. Insights into the electrochemical processes reveal the hybrid composite exhibits enhanced redox capacitance and interfacial capacitance in comparison with SnO2 nanocrystals which indicate the perfect interfaces and robust structure of the hybrid composite. [Copyright &y& Elsevier]

Fe3O4–carbon nanocomposites have been synthesized simply with a hydrothermal method free of template that is followed by an annealing process. The morphological and compositional analysis reveals that the inter-separated Fe3O4 nanocrystals with a size of ~10 nm are homogeneously embedded within the mesoporous carbon matrix. The interesting configuration is evaluated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman, energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). Benefiting from the advantages of good buffering and electric conductivity, the nanocomposite delivers an initial capacity of 1706 mAh g−1 at 0.2 C (1 C = 1 A g−1). Besides excellent lithium storage capability, it exhibits a superior cycling stability with more than 100% capacity retention after 100 cycles at 0.2 C and 1 C. When successively discharging at variable rates, the nanocomposite retains a reversible capacity of 1249 mAh g−1 at 0.1 C, 690 mAh g−1 at 1 C, and 311 mAh g−1 at 10 C. With excellent capability and rate performance, the Fe3O4–carbon nanocomposites may be a promising anode material of lithium ion batteries (LIBs) for the green large-scale production. [ABSTRACT FROM AUTHOR]

Novel nanostructures, e.g. core–shell or yolk–shell, sword–sheath, coaxial nanotubes, etc., are extensively explored for their potential application in modifying electrode durability in lithium-ion batteries (LIBs). Herein, hybrid nanostructures of monodisperse tin dioxide nanocrystals inclusion in highly ordered mesotunnels of mesoporous carbon (CMK-3) are hydrothermally synthesized. Benefiting from ultrafine nanocrystals of mainly 2 nm or so and their good distribution throughout the highly ordered tunnels and the outer surface of the CMK-3, the hybrid shows a strongly coupled synergistic effect. When used as anode materials for LIBs, the hybrid composite exhibits excellent cycling and rate performance superior to both components involved with high reversible capacity retention above 95% for 200 cycles and recoverable initial reversible capacity at large rates of 10 A g−1. Insights into the electrochemical process reveal the total capacity is contributed by two different factors: redox capacitance and interfacial capacitance. Once solid electrolyte interfaces (SEIs) are formed, the hybrid composite exhibits stable interfaces and robust structures indicated by the enhanced interfacial capacitance. [ABSTRACT FROM AUTHOR]

The use of nanodiamonds to improve the photocatalytic hydrogen evolution reaction of Cu2O by nanocomposition is demonstrated for the first time by Guowei Yang and co‐workers in article number 1501865. Compared with pure Cu2O, this nanocomposite shows a tremendous improvement in performance. It is also established that the broad spectral response and electron injection from nanodiamond to Cu2O play a dominant role. [ABSTRACT FROM AUTHOR]