Flat carbon (sp
2
and sp) networks endow the graphdiyne and graphyne families with high degrees of π-conjunction, uniformly distributed pores, and tunable electronic properties; therefore, these ...materials are attracting much attention from structural, theoretical, and synthetic scientists wishing to take advantage of their promising electronic, optical, and mechanical properties. In this Review, we summarize a state-of-the-art research into graphdiynes and graphynes, with a focus on the latest theoretical and experimental results. In addition to the many theoretical predictions of the potential properties of graphdiynes and graphynes, we also discuss experimental attempts to synthesize and apply graphdiynes in the areas of electronics, photovoltaics, and catalysis.
This review demonstrates the theoretical and experimental results of studies of graphdiynes and graphynes, and also the application of graphdiynes in electronics, photovoltaics and catalysis.
Conspectus Graphdiyne (GDY) is a flat material comprising sp2- and sp-hybridized carbon atoms with high degrees of π conjugation that features uniformly distributed pores. It is interesting not only ...from a structural point of view but also from the perspective of its electronic, chemical, mechanical, and magnetic properties. We have developed an in situ homocoupling reaction of hexaethynylbenzene on Cu foil for the fabrication of large-area ordered films of graphdiyne. These films are uniform and composed of graphdiyne multilayers. The conductivity of graphdiyne films, calculated at 2.52 × 10–4 S m–1, is comparable to that of Si, suggesting excellent semiconducting properties. Through morphology-controlled syntheses, we have prepared several well-defined graphdiyne structures (e.g., nanotubes, nanowires, and nanowalls) having distinct properties. The graphdiyne nanotube arrays and graphdiyne nanowalls exhibited excellent field emission performance, higher than that of some other semiconductors such as graphite and carbon nanotubes. These structures have several promising applications, for example, as energy storage materials and as anode materials in batteries. The unique atomic arrangement and electronic structure of graphdiyne also inspired us to use it to develop highly efficient catalysts; indeed, its low reduction potential and highly conjugated electronic structure allow graphdiyne to be used as a reducing agent and stabilizer for the electroless deposition of highly dispersed and surfactant-free Pd clusters. GDY-based three-dimensional (3D) nanoarchitectures featuring well-defined porous network structures can function as highly active cathodes for H2 evolution. Heteroatom-doped GDY structures are excellent metal-free electrocatalysts for the oxygen reduction reaction (ORR). Its excellent electrocatalytic activity and inexpensive, convenient, and scalable preparation make GDY a promising candidate for practical and efficient energy applications; indeed, we have explored the application of GDY as a highly efficient lithium storage material and have elucidated the method through which lithium storage occurs in multilayer GDY. Lithium-ion batteries featuring GDY-based electrodes display excellent electrochemical performance, including high specific capacity, outstanding rate performance, and long cycle life. We have also explored the application of GDY in energy conversion and found that it exhibits excellent conductivity. In this Account, we summarize the relationships between the functions of graphdiyne and its well-defined nanostructures. Our results suggest that GDY is a novel 2D carbon material possessing many attractive properties. It can be designed into new nanostructures and materials across a range of compositions, sizes, shapes, and functionalities and can be applied in the fields of electronics, optics, energy, and optoelectronics.
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IJS, KILJ, NUK, PNG, UL, UM
The oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and overall water splitting are major energy and chemical conversion efforts. Progress in electrocatalytic reactions have shown ...that the future is limitless in many fields. However, it is urgent to develop efficient electrocatalysts. Here, the first graphdiyne‐supported efficient and bifunctional electrocatalyst is reported using 3D graphdiyne foam as scaffolds, and NiCo2S4 nanowires as building blocks (NiCo2S4 NW/GDF). NiCo2S4 NW/GDF exhibits outstanding catalytic activity and stability toward both OER and HER, as well as overall water splitting in alkaline media. Remarkably, it enables a high‐performance alkaline water electrolyzer with 10 and 20 mA cm−2 at very low cell voltages of 1.53 and 1.56 V, respectively, and remarkable stability over 140 h of continuous electrolysis operation at 20 mA cm−2. The results indicate that this catalyst has a bifunction that overcomes all reported bifunctional, nonprecious‐metal‐based ones.
The first graphdiyne (GD)‐based highly‐efficient overall water‐splitting catalyst (NiCo2S4 nanowire/GD foam) is prepared through a facile, scalable strategy. It shows an unprecedented catalytic activity and stability toward both oxygen evolution and hydrogen evolution reactions, as well as overall water splitting in alkaline media. Such a GD‐based bifunctional electrocatalyst is likely to lead to breakthroughs and new understandings of electrocatalysis.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Electrocatalysis by atomic catalysts is a major focus of chemical and energy conversion effort. Although transition-metal-based bulk electrocatalysts for electrochemical application on energy ...conversion processes have been reported frequently, anchoring the stable transition-metal atoms (e.g. nickel and iron) still remains a practical challenge. Here we report a strategy for fabrication of ACs comprising only isolated nickel/iron atoms anchored on graphdiyne. Our findings identify the very narrow size distributions of both nickel (1.23 Å) and iron (1.02 Å), typical sizes of single-atom nickel and iron. The precision of this method motivates us to develop a general approach in the field of single-atom transition-metal catalysis. Such atomic catalysts have high catalytic activity and stability for hydrogen evolution reactions.
Conjugated organic molecules are interesting materials because of their structures and their electronic, electrical, magnetic, optical, biological, and chemical properties. However, researchers ...continue to face great challenges in the construction of well-defined organic compounds that aggregate into larger molecular materials such as nanowires, tubes, rods, particles, walls, films, and other structural arrays. Such nanoscale materials could serve as direct device components. In this Account, we describe our recent progress in the construction of nanostructures formed through the aggregation of organic conjugated molecules and in the investigation of the optical, electrical, and electronic properties that depend on the size or morphology of these nanostructures. We have designed and synthesized functional conjugated organic molecules with structural features that favor assembly into aggregate nanostructures via weak intermolecular interactions. These large-area ordered molecular aggregate nanostructures are based on a variety of simpler structures such as fullerenes, perylenes, anthracenes, porphyrins, polydiacetylenes, and their derivatives. We have developed new methods to construct these larger structures including organic vapor−solid phase reaction, natural growth, association via self-polymerization and self-organization, and a combination of self-assembly and electrochemical growth. These methods are both facile and reliable, allowing us to produce ordered and aligned aggregate nanostructures, such as large-area arrays of nanowires, nanorods, and nanotubes. In addition, we can synthesize nanoscale materials with controlled properties. Large-area ordered aggregate nanostructures exhibit interesting electrical, optical, and optoelectronic properties. We also describe the preparation of large-area aggregate nanostructures of charge transfer (CT) complexes using an organic solid-phase reaction technique. By this process, we can finely control the morphologies and sizes of the organic nanostructures on wires, tubes, and rods. Through field emission studies, we demonstrate that the films made from arrays of CT complexes are a new kind of cathode materials, and we systematically investigate the effects of size and morphology on electrical properties. Low-dimension organic/inorganic hybrid nanostructures can be used to produce new classes of organic/inorganic solid materials with properties that are not observed in either the individual nanosize components or the larger bulk materials. We developed the combined self-assembly and templating technique to construct various nanostructured arrays of organic and inorganic semiconductors. The combination of hybrid aggregate nanostructures displays distinct optical and electrical properties compared with their individual components. Such hybrid structures show promise for applications in electronics, optics, photovoltaic cells, and biology. In this Account, we aim to provide an intuition for understanding the structure−function relationships in organic molecular materials. Such principles could lead to new design concepts for the development of new nonhazardous, high-performance molecular materials on aggregate nanostructures.
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The Central Asian Orogenic Belt (CAOB, also known as the Altaid Tectonic Collage), one of the largest and long-lived accretionary orogens in the world, developed from ca. 600Ma to 250Ma by multiple ...accretions of terranes of different origin. Despite extensive research aimed at understanding tectonic evolution of the CAOB and the evolution of the Paleo-Asian Ocean, the subduction–accretion mechanism of the CAOB remains controversial. The West Junggar, northwestern China, is located in the southwest of the CAOB and consists of Paleozoic ophiolitic mélanges, arcs and accretionary complexes.
The ophiolitic mélanges in West Junggar are generally complicated and usually consist of metamorphic peridotite (serpentinite), cumulates, gabbros, basaltic lavas (pillows), and abyssal radiolarian cherts. However, sheeted dike complexes are extremely rare and, where present, usually form small, isolated bodies. The formation age of ophiolitic mélanges in West Junggar has been determined generally as early Paleozoic except for the Darbut and Karamay ophiolitic mélanges with the age ranging from Early–Middle Devonian to Late Carboniferous. The Darbut and Karamay ophiolitic mélanges have distinct unconformable or fault contacts with Lower Devonian to Lower Carboniferous volcano-sedimentary rocks consisting mainly of sandstone, basalt, tuff and volcanic breccia. The strata deposited on the Tangbale and Mayile ophiolitic mélanges are early Paleozoic and dominated by Ordovician–Silurian volcano-sedimentary rocks.
The alkaline basalts in the Tangbale, Mayile, Darbut and Karamay ophiolitic mélanges occur as tectonic blocks within the mélanges which are composed of pelagic limestones, siliceous mudstone and radiolarian chert, possessing formation characteristics of seamounts (oceanic islands/plateaus). The alkaline basalts are characterized by LREE enrichment and HREE depletion, very weak or no Eu anomalies, and no obvious Nb, Ta and Ti negative anomalies, suggesting typical OIB affinity. The OIB-type rocks in ophiolitic mélanges are considered as accreted seamount fragments in West Junggar accretionary complex, and may represent mantle transition zone plume-related magmatism within the Paleo-Asian Ocean. Therefore, we propose the following tectonic evolutionary history of the West Junggar.
The seamounts formed in West Junggar as well as the Paleo-Asian Ocean at Neoproterozoic. With progressive evolution of the Paleo-Asian Ocean, subduction of the oceanic lithosphere commenced during late Cambrian to early Ordovician, resulted in the seamounts eventually accreted in the fore-arc with oceanic fragments forming the Tangbale and Mayile ophiolitic mélanges. As retreat of the subducting slab, the subduction–accretion processes may have continued in the late Paleozoic, given rise to form the Darbut and karamay ophiolitic mélange with the OIB-type rocks from seamounts. Based on our observations, and in combination with previous work, we suggest that the intra-plate magmatism in the CAOB might generally continuous during the development of the Paleo-Asian Ocean from the Late Neoproterozoic to the Mesozoic. Therefore, we present a new model that is multiple intra-oceanic subduction with seamount accretion for the CAOB, which can better explain the tectonic evolution of the CAOB.
•The ages of West Junggar ophiolitic mélanges range from 572Ma to 332Ma.•Alkaline basalts characterized with OIB affinity and formed in seamounts•OIB-type rocks may relate to mantle transition zone plume within the Paleo-Asian Ocean.•The multiple intra-oceanic subduction with seamount accretion model for the CAOB
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Due to good reactivity of fluorinated (meth)acrylates with other monomers or polymer segments, fluorinated poly(meth)acrylates possess more economical and convenient synthesis routes than other ...fluoropolymers. This feature article initially summarizes different types of fluorinated (meth)acrylates, which can be divided into fluorinated alkyl (meth)acrylates and fluorinated aryl (meth)acrylates. Subsequently, various approaches for synthesizing fluorinated poly(meth)acrylates including random, block, graft or star copolymers are described. Conventional free radical polymerization can be used in synthesizing random copolymers, while controlled/“living” radical polymerization can provide well-defined copolymers with accurate control over molecular weight and special structures as expected. In particular, introduction of fluorinated components into as-prepared copolymers offers an alternative route to synthesize fluorinated poly(meth)acrylates which are difficult to be obtained directly via polymerization. The incorporation of fluorine can confer unique and highly desirable properties to poly(meth)acrylates such as low surface energy, thermal stability, chemical and weather resistance, low refractive index, and self-organization characteristics. Such properties are described in great details based on many recent articles.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
We report co-infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza A virus in a patient with pneumonia in China. The case highlights possible co-detection of known ...respiratory viruses. We noted low sensitivity of upper respiratory specimens for SARS-CoV-2, which could further complicate recognition of the full extent of disease.
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DOBA, IZUM, KILJ, NUK, ODKLJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Eighteen novel chalcone derivatives containing indole and naphthalene moieties (2–19) were synthesized and characterized by 1H-NMR, 13C-NMR and high resolution (HR)-MS spectra. All compounds were ...evaluated for their in vitro cytotoxic potential against human hepatocellular carcinoma (HepG2), human colon carcinoma (HCT116) and human breast adenocarcinoma (MCF-7) cell lines. Among them, compound 2, 3, 4 and 7 showed potent activities against tested cancer cell lines. More significantly, compound 7 exhibited the most potent cytotoxic activity against HepG2, HCT116 and MCF-7 with IC50 values of 0.65, 1.13 and 0.82 µM, respectively. Furthermore, flow cytometry analysis indicated that compound 7 arrested cancer cells in G2/M phase. The compound 7 also displayed significant inhibition of tubulin polymerization (IC50 = 3.9 µM). Finally, molecular docking studies were performed to explore the possible interactions between compound 7 and tubulin binding pockets.
In this paper, the customized experimental spraying platform for dust control was used to study the atomization characteristics and dust reduction performance of the internal-mixing air-assisted ...atomizer nozzles under different structural parameters. Finally, based on the comprehensive consideration of the factors including the dust reduction efficiency and flow rate of the nozzle, the reasonable structure parameters for the nozzle were obtained.
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•The internal-mixing air-assisted atomizer nozzles with different structural parameters were studied.•The efficiency was optimal when the diameter of the water-injection hole was 1.5mm and the number of air-injections holes was 4.•Based on the comprehensive consideration, the diameter of the air cap outlet should be in the range of 2.0–3.0 mm.
As a air-liquid two-phase flow nozzle, the internal-mixing air-assisted atomizer nozzle has been widely used in the field of spray technology for dust reduction. Structural parameters are important factors to influence the atomization characteristics and dust-reducing performance of the atomizing nozzle. However, the mechanism of the influences of the structural parameters is not clear. In this study, the customized experimental spraying platform for dust control was used to study the atomization characteristics and dust reduction performance of the nozzles under different structural parameters. Based on the experimental results, when the parameters such as water pressure and air pressure were constant, the dust reduction efficiency for both the total dust and the respiratory dust first increased then decreased with the increase of the diameter of the water-injection hole in the liquid cap and the number of air-injections holes. The dust reduction efficiency was optimal when the diameter of the water-injection hole in the liquid cap was 1.5mm and the number of air-injections holes was 4. As the diameter of the air cap outlet increased, the dust reduction efficiency for both the total dust and the respiratory dust was improved; however, the improvement was limited. Based on the comprehensive consideration of the factors including the dust reduction efficiency of the nozzle, the water flow rate, and the air flow rate, the diameter of the air cap outlet should be in the range of 2.0˜3.0mm. When an internal mixing air atomizing nozzle was used for dust reduction in industrial production sites, it is recommended have the diameter of the water-injection hole to be 1.5mm, the number of air-injection holes to be 4, and the diameter of the air cap outlet to be 2.0˜3.0mm. Under these recommended structural parameters, the dust reduction performance of the nozzle is good while the water consumption and air consumption remain relatively low.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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