Asymmetric Monolayer Mesoporous Nanosheets of Regularly Arranged Semi-Opened Pores via a Dual-Emulsion-Directed Micelle Assembly.

Constructing asymmetric two-dimensional (2D) mesoporous nanomaterials with new pore structure, tunable monolayer architectures, and especially anisotropic surfaces remains a great challenge in materials science. Here, we report a dual-emulsion directed micelle assembly approach to fabricate a novel type of asymmetric monolayer mesoporous organosilica nanosheet for the first time. In this asymmetric 2D structure, numerous quasi-spherical semiopened mesopores (∼20 nm in diameter, 24 nm in opening size) were regularly arranged on a plane, endowing the porous nanosheets (several micrometers in size) with a typical surface anisotropy on two sides. Meanwhile, lots of triangular intervoids (4.0-5.0 nm in size) can also be found among each three semiopened mesopores, enabling the nanosheet to be interconnected. Vitally, such interconnected, anisotropic porous nanosheets exhibit ultrahigh accessible surface area (∼714 m2 g-1) and good lipophilicity properties owing to the abundant semiopened mesopores. Additionally, besides the nanosheet, the configuration of the asymmetric porous structure can also be transformed into a microcapsule when controlling the emulsification size via a facile ultrasonic treatment. As a demonstration, we show that the asymmetric microcapsule shows a high demulsification efficiency (>98%) and cyclic stability (>6 recycle times). Our protocol opens up a new avenue for developing next-generation asymmetric mesoporous materials for various applications.

Constructing Unique Mesoporous Carbon Superstructures via Monomicelle Interface Confined Assembly.

Constructing hierarchical three-dimensional (3D) mesostructures with unique pore structure, controllable morphology, highly accessible surface area, and appealing functionality remains a great challenge in materials science. Here, we report a monomicelle interface confined assembly approach to fabricate an unprecedented type of 3D mesoporous N-doped carbon superstructure for the first time. In this hierarchical structure, a large hollow locates in the center (∼300 nm in diameter), and an ultrathin monolayer of spherical mesopores (∼22 nm) uniformly distributes on the hollow shells. Meanwhile, a small hole (4.0-4.5 nm) is also created on the interior surface of each small spherical mesopore, enabling the superstructure to be totally interconnected. Vitally, such interconnected porous supraparticles exhibit ultrahigh accessible surface area (685 m2 g-1) and good underwater aerophilicity due to the abundant spherical mesopores. Additionally, the number (70-150) of spherical mesopores, particle size (22 and 42 nm), and shell thickness (4.0-26 nm) of the supraparticles can all be accurately manipulated. Besides this spherical morphology, other configurations involving 3D hollow nanovesicles and 2D nanosheets were also obtained. Finally, we manifest the mesoporous carbon superstructure as an advanced electrocatalytic material with a half-wave potential of 0.82 V (vs RHE), equivalent to the value of the commercial Pt/C electrode, and notable durability for oxygen reduction reaction (ORR).

Modular super-assembly of hierarchical superstructures from monomicelle building blocks.

Manipulating the super-assembly of polymeric building blocks still remains a great challenge due to their thermodynamic instability. Here, we report on a type of three-dimensional hierarchical core-satellite SiO2@monomicelle spherical superstructures via a previously unexplored monomicelle interfacial super-assembly route. Notably, in this superstructure, an ultrathin single layer of monomicelle subunits (~18 nm) appears in a typically hexagon-like regular discontinuous distribution (adjacent micelle distance of ~30 nm) on solid spherical interfaces (SiO2), which is difficult to achieve by conventional super-assembled methods. Besides, the number of the monomicelles on colloidal SiO2 interfaces can be quantitatively controlled (from 76 to 180). This quantitative control can be precisely manipulated by tuning the interparticle electrostatic interactions (the intermicellar electrostatic repulsion and electrostatic attractions between the monomicelle units and the SiO2 substrate). This monomicelle interfacial super-assembly strategy will enable a controllable way for building multiscale hierarchical regular micro- and/or macroscale materials and devices.

Research on Alleviating Children's Nighttime Fear Using a Digital Game.

Nighttime fear is common among children and may negatively affect their growth. Given the positive role of digital games in regulating children's emotions, in this study, we proposed principles for the design of a digital game to alleviate children's nighttime fears and developed a game prototype based on a survey of children and their parents. In order to verify whether digital games can reduce children's fears, the Koala Fear Questionnaire (KFQ) was used to assess the effectiveness of the game prototype in an experiment. We adopted a quasi-experimental design with non-randomized samples, including 47 subjects in the experimental group (EG) and 49 subjects in the control group (CG). The results of the analysis show that the children in the EG displayed an obvious decrease in their fear of the objects that appeared in the game. Moreover, for some children with a moderate level of fear, playing digital games could significantly reduce their fear. Therefore, this preliminary study suggests that digital games have a positive effect on alleviating children's nighttime fears.

Bioinspired Nanocomposites with Self-Adaptive Stress Dispersion for Super-Foldable Electrodes.

In flexible electronics, appropriate inlaid structures for stress dispersion to avoid excessive deformation that can break chemical bonds are lacking, which greatly hinders the fabrication of super-foldable composite materials capable of sustaining numerous times of true-folding. Here, mimicking the microstructures of both cuit cocoon possessing super-flexible property and Mimosa leaf featuring reversible scatheless folding, super-foldable C-web/FeOOH-nanocone (SFCFe) conductive nanocomposites are prepared, which display cone-arrays on fiber structures similar to Mimosa leaf, as well as non-crosslinked junctions, slidable nanofibers, separable layers, and compressible network like cuit cocoon. Remarkably, the SFCFe can undergo over 100 000 times of repeated true-folding without structural damage or electrical conductivity degradation. The mechanism underlying this super-foldable performance is further investigated by real-time scanning electron microscopy folding characterization and finite-element simulations. The results indicate its self-adaptive stress-dispersion mechanism originating from multilevel biomimetic structures. Notably, the SFCFe demonstrates its prospect as a super-foldable anode electrode for aqueous batteries, which shows not only high capacities and satisfactory cycling stability, but also completely coincident cyclic voltammetry and galvanostatic charge-discharge curves throughout the 100 000 times of true-folding. This work reports a mechanical design considering the self-adaptive stress dispersion mechanism, which can realize a scatheless super-foldable electrode for soft-matter electronics.

Direct Superassemblies of Freestanding Metal-Carbon Frameworks Featuring Reversible Crystalline-Phase Transformation for Electrochemical Sodium Storage.

High-power sodium-ion batteries (SIBs) with long-term cycling attract increasing attention for large-scale energy storage. However, traditional SIBs toward practical applications still suffer from low rate capability and poor cycle induced by pulverization and amorphorization of anodes at high rate (over 5 C) during the fast ion insertion/extraction process. The present work demonstrates a robust strategy for a variety of (Sb-C, Bi-C, Sn-C, Ge-C, Sb-Bi-C) freestanding metal-carbon framework thin films via a space-confined superassembly (SCSA) strategy. The sodium-ion battery employing the Sb-C framework exhibits an unprecedented performance with a high specific capacity of 246 mAh g-1, long life cycle (5000 cycles), and superb capacity retention (almost 100%) at a high rate of 7.5 C (3.51A g-1). Further investigation indicates that the unique framework structure enables unusual reversible crystalline-phase transformation, guaranteeing the fast and long-cyclability sodium storage. This study may open an avenue to developing long-cycle-life and high-power SIBs for practical energy applications.

Graphene stabilized ultra-small CuNi nanocomposite with high activity and recyclability toward catalysing the reduction of aromatic nitro-compounds.

Nowadays, it is of great significance and a challenge to design a noble-metal-free catalyst with high activity and a long lifetime for the reduction of aromatic nitro-compounds. Here, a 2D structured nanocomposite catalyst with graphene supported CuNi alloy nanoparticles (NPs) is prepared, and is promising for meeting the requirements of green chemistry. In this graphene/CuNi nanocomposite, the ultra-small CuNi nanoparticles (∼2 nm) are evenly anchored on graphene sheets, which is not only a breakthrough in the structures, but also brings about an outstanding performance in activity and stability. Combined with a precise optimization of the alloy ratios, the reaction rate constant of graphene/Cu61Ni39 reached a high level of 0.13685 s(-1), with a desirable selectivity as high as 99% for various aromatic nitro-compounds. What's more, the catalyst exhibited a unprecedented long lifetime because it could be recycled over 25 times without obvious performance decay or even a morphology change. This work showed the promise and great potential of noble-metal-free catalysts in green chemistry.

Fabrication of Cu@AgCl nanocables for their enhanced activity toward the catalytic degradation of 4-chlorophenol.

Partial and full AgCl nanoparticles (NPs) covered Cu@AgCl nanocables were fabricated based on Cu nanowires (NWs) through structure-director-induced assembly process in this work. The full covered Cu@AgCl nanocables, with the average diameter of ∼50nm, consist of Cu NWs core at diameter of ∼20nm and outer AgCl NPs shells with thickness of ∼15nm. Using as UV-driven photocatalysts, as-designed Cu@AgCl nanocables exhibit high performance and stability for the catalytic degradation of 4-chlorophenol pollutants. Compared with the as-prepared Cu NWs, AgCl NPs, partial AgCl NPs covered Cu@AgCl nanocables and the reference photocatalysts P25-TiO2, full AgCl NPs covered Cu@AgCl nanocables exhibit much higher photocatalytic activity (nearly 91% conversion) toward the degradation of 4-chlorophenol with the reaction rate constant (k) of 0.026min(-1). Cu NWs are found to play important roles in quickly transferring photoelectrons, facilitating more effective separation of photoinduced electrons and holes and reducing the charge recombination due to their the high conductivity.

Assembly synthesis of Cu2O-on-Cu nanowires with visible-light-enhanced photocatalytic activity.

New Cu2O-on-Cu nanowires (NWs) are constructed to develop the visible-light-driven activity of photocatalysts via the facile self-assembly of Cu2O nanoparticles (NPs) on a Cu NW surface assisted by a structure director, followed in situ reduction. In the resultant Cu2O-on-Cu NWs, the Cu2O NPs, with a diameter of 10 nm, show good distribution on the 50 nm-sized Cu single-crystal NWs. Owing to the band-gap adjusting effect and high electron transportation, the coupling of narrow-band-gap semiconductor Cu2O and excellent conductor Cu can lead to the markedly enhanced high visible light photocatalytic activity of Cu2O-on-Cu NWs toward the degradation of dye pollutants including Rhodamine B (RhB), methyl orange (MO) and methyl blue (MB). The as-designed Cu2O-on-Cu heterostructured NWs exhibit higher performance for the catalytic degradation of dye compounds than pure Cu2O. Nearly 60%, 100%, and 85% conversion with reaction rate constants (k) of 0.0137, 0.0746 and 0.0599 min(-1) can be achieved for the degradation of RhB, MO and MB, respectively. Besides the highly efficient transportation of electrons, Cu NWs have a strong capacity for oxygen activation, which results in the gathering of negative charges and rich chemisorbed oxygen onto the surface. This may be responsible for the high catalytic efficiency of the Cu2O-on-Cu NWs toward the degradation of organic pollutants.

Assembly of TiO2 -on-Cu2 O Nanocubes with Narrow-Band Cu2 O-Induced Visible-Light-Enhanced Photocatalytic Activity.

Newly designed TiO2 -on-Cu2 O nanocubes have been constructed as visible-light-driven photocatalysts with high efficiency by means of a facile self-assembly approach at room temperature. In the resultant TiO2 -on-Cu2 O nanocubes, the TiO2 nanoparticles with a diameter of 6-8 nm show a well-monodispersed distribution of the 200-300 nm-sized Cu2 O single-crystal nanocubes, which can form sub-monolayer, monolayer, and multilayer coverage through controlling the ratio of the two phases. In particular, the coupling of the wide-bandgap semiconductor TiO2 with narrow-bandgap Cu2 O can lead to the markedly enhanced high visible-light photocatalytic activity in the TiO2 -on-Cu2 O nanocomposite systems toward the photodegradation of rhodamine B, which is induced by the bandgap-adjusting effect. This promising self-assembly route can be extended to the preparation of other nanocomposite materials.