The oxygen evolution reaction (OER) is involved in various renewable energy systems,such as water-splitting cells and metal-air batteries.N i-Fel ayered double hydroxides (LDHs) have been reported as promising OER electrocatalysts in alkaline electrolytes.T he rational design of advanced nanostructures for Ni-FeLDHs is highly desirable to optimize their electrocatalytic performance.H erein, we report af acile self-templated strategy for the synthesis of novel hierarchical hollown anoprisms composed of ultrathin Ni-FeL DH nanosheets.T etragonal nanoprisms of nickel precursors were first synthesized as the self-sacrificing template.A fterwards, these Ni precursors were consumed during the hydrolysis of iron(II) sulfate for the simultaneous growth of al ayer of Ni-FeL DH nanosheets on the surface.T he resultant Ni-FeL DH hollow prisms with large surface areas manifest high electrocatalytic activity towards the OER with lowo verpotential, small Tafel slope,and remarkable stability.

Metal-organic frameworks (MOFs) have been intensively used as the templates/precursors to synthesize complex hollow structures for various energy-related applications. Herein we report a facile two-step diffusion-controlled strategy to generate novel MOFs derived hierarchical hollow prisms composed of Nanosized CoS bubble-like subunits. Uniform zeolitic imidazolate framework-67 (ZIF-67) hollow prisms assembled by interconnected nanopolyhedra are first synthesized via a transformation process. Afterwards, these ZIF-67 building blocks are converted into CoS bubble-like hollow particles to form the complex hollow prisms through a sulfidation reaction with an additional annealing treatment. When evaluated as an electrode material for lithium-ion batteries, the as-obtained CoS nanobubble hollow prisms show remarkable electrochemical performance with good rate capability and long cycle life.

Electrospinning is a popular technique to prepare 1D tubular/fibrous nanomaterials that assemble into 2D/3D architectures. When combined with other material processing techniques such as chemical vapor deposition and hydrothermal treatment, electrospinning enables powerful synthesis strategies that can tailor structural and compositional features of energy storage materials. Herein, a simple description is given of the basic electrospinning technique and its combination with other synthetic approaches. Then its employment in the preparation of frameworks and scaffolds with various functions is introduced, e.g., a graphitic tubular network to enhance the electronic conductivity and structural integrity of the electrodes. Current developments in 3D scaffold structures as a host for Li metal anodes, sulfur cathodes, membrane separators, or as a 3D matrix for polymeric solid‐state electrolytes for rechargeable batteries are presented. The use of 1D electrospun nanomaterials as a nanoreactor for in situ transmission electron microscopy (TEM) observations of the mechanisms of materials synthesis and electrochemical reactions is summarized, which has gained popularity due to easy mechanical manipulation, electron transparency, electronic conductivity, and the easy prepositioning of complex chemical ingredients by liquid‐solution processing. Finally, an outlook on industrial production and future challenges for energy storage materials is given.

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Pyrolyzed Fe/N/C is one of the most promising non-precious-metal catalysts for the oxygen reduction reaction (ORR), which is supposed to boost the commercialization of proton exchange membrane fuel cells (PEMFC). However, the nature of the active sites of Fe/N/C is not clear and has long been debated. The challenges mainly come from highly heterogeneous structures formed during the pyrolysis process as well as no suitable surface probes. To elucidate the active sites, the most effective approach is building well-defined model catalysts as single-crystal planes in surface sciences. Herein, we designed a single-atomic-layer Fe/ N/C model catalyst based on monolayer graphene (FeN-MLG) to explore the active sites. The model catalyst was prepared by 950 °C heat treatment of graphene with controlled defects under an FeCl 3 (g)/NH 3 atmosphere. The as-prepared model catalyst exhibits ORR activity and SCN − suppressive effect comparable to those of normal nanoparticle-like Fe/N/C catalysts, indicating that active sites are successfully created in the model catalyst. The effect of defect density, the layer number of graphene, and nitrogen species on the ORR activity has been investigated. The main content of nitrogen species on FeN-MLG is N x -Fe, and quantitative correlation between N x -Fe and ORR activity demonstrates that N x -Fe species are the active site of Fe/N/C catalysts. The proposed model catalyst serves to simplify the catalyst structures and to simulate the topmost atomic layer of normal Fe/N/C, where ORR is catalyzed. This model system opens an opportunity to further understand the highly heterogeneous Fe/N/C catalysts.

Developing extra safety encryption technologies to prevent information leakage and combat fakes is in high demand but is challenging. Herein, we propose a "double lock" strategy based on both lower critical solution temperature (LCST) and upper critical solution temperature (UCST) polymer hydrogels for information camouflage and multilevel encryption. Two types of hydrogels were synthesized by the method of random copolymerization. The number of À COÀ NH 2 groups in the network structure of the hydrogels changed the enthalpic or entropic thermo-responsive hydrogels, and ultimately precisely controlled their phase transition temperature. The crosslink density of the polymer hydrogels governs the diffusion kinetics, resulting in a difference in the time for their color change. The combination of multiple LCST and UCST hydrogels in one label realized information encryption and dynamic information identification in the dimensions of both time and temperature. This work is highly interesting for the fields of information encryption, anti-counterfeiting, and smart responsive materials.

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Z. (2023). Growth of single-crystal imine-linked covalent organic frameworks using amphiphilic amino-acid derivatives in water. Nature Chemistry.