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The development of low-cost, catalytically efficient, and durable earth-abundant electrocatalysts for replacing platinum-group-metal (PGM) materials has always been at the forefront of materials engineering for sustainable hydrogen generation. Metal–organic frameworks (MOFs), especially cobalt (Co)-based zeolitic imidazolate framework (ZIF-67) can be used as precursors or templates for preparing non-precious electrocatalysts. Herein, we successfully fabricated metallic cobalt/cobalt sulfide hetero-nanostructures embedded within N-doped graphitic carbon nanocages (Co/CoxSy@NC-750) by the one-step pyrolysis of ZIF-67 under H2 and S. Co/CoxSy@NC-750 exhibits a hollow configuration with a high degree of morphological uniformity. The pyrolysis temperature and resulting control of the composition played a crucial role in material engineering with application-oriented properties. Examination of the activity for the hydrogen evolution reaction (HER) in 0.5 M H2SO4 and 1.0 M KOH aqueous electrolytes demonstrated that Co/CoxSy@NC-750 exhibits substantially improved HER performance in both acidic (overpotential of 130 mV and Tafel slope of 82 mV dec−1) and basic (330 mV and 160 mV dec−1) media. The unique metallic cobalt core/cobalt sulfide shell is particularly beneficial for maintaining the electrochemical long-term durability (≥30 h and 40 h in acids and bases, respectively). This study provides guidance for achieving MOF-derived inorganic nanomaterials with the desired structural heterogeneity and compositional control for non-PGM electrochemical catalysis through fundamental quantification of the structural and catalytic parameters. [ABSTRACT FROM AUTHOR]

Metal chalcogenides are promising candidates for various energy storage applications. Herein, a ternary Fe2GeS4 compound was synthesized using a simple solid-state method and applied as versatile electrodes for rechargeable Li/Na–Fe2GeS4 battery cathodes and Li/Na-ion battery anodes. In addition, distinctive Li and Na reaction pathways for Fe2GeS4 consisting of insertion and conversion reactions have been demonstrated. For its application as rechargeable Li/Na–Fe2GeS4 battery cathodes, Li‖Fe2GeS4 and Na‖Fe2GeS4 battery systems were electrochemically evaluated by controlling the cut-off voltages within the insertion reaction and they showed high electrochemical performance with high reversible volumetric capacities and cyclability with appropriate cell potentials (Li‖Fe2GeS4: ∼550 mA h cm−3 over 100 cycles with ∼1.6 V; Na‖Fe2GeS4: ∼555 mA h cm−3 over 100 cycles with ∼1.2 V). In addition, for using Fe2GeS4 as an anode for Li-ion batteries (LIBs) and Na-ion batteries (NIBs), graphene-wrapped Fe2GeS4 nanocomposite (Fe2GeS4-rGO) comprising Fe2GeS4 nanocrystallites (∼10–15 nm) embedded on reduced graphene oxide (rGO) was synthesized through a simple two-step synthetic method to improve the electronic/ionic conductivity, structural stability, and mechanical strain relaxation. The electrochemical test results indicated that the Fe2GeS4-rGO exhibited high initial reversible gravimetric capacities (730 mA h g−1 for LIB, 563 mA h g−1 for NIB), high rate capability (520 mA h g−1 at 3C for LIB, 470 mA h g−1 at 2C for NIB), and an excellent cycling performance at a high 1C rate (capacity retention: ∼100% over 500 cycles for LIBs, ∼93% over 200 cycles for NIBs). Therefore, we believe that Fe2GeS4 is a highly applicable compound material for various battery systems. [ABSTRACT FROM AUTHOR]

The development of high-capacity and high-power lithium-ion batteries (LIBs) is a key challenge to meet the increasing demand for advanced mobile electronics and electric vehicles. A novel high-capacity and high-power Ga2Te3 anode material for LIBs, which exhibits a distinctive reaction mechanism with Li ions, has been introduced in this study. Two types of Ga2Te3/C composite were prepared via different synthetic routes, namely carbon thermal decomposition (TD) and high-energy ball milling (BM), to improve the electrochemical performance of Ga2Te3 anodes, and their electrochemical performances were compared. The electrochemical evaluation results indicate that the Ga2Te3/C composite produced by BM (BM-Ga2Te3/C) showed better electrochemical performance by delivering much smaller Ga2Te3 nanocrystallites than the Ga2Te3/C composite produced by TD (TD-Ga2Te3/C). Furthermore, the BM-Ga2Te3/C anode showed a highly reversible initial volumetric capacity (1245 mA h cm−3), stable capacity retention (93.2% after 500 cycles), and excellent high-rate performance (∼1000 mA h cm−3 at 1C after 500 cycles). These high electrochemical performances, which were demonstrated via ex situ analyses, were attained by a unique three-step nano-confinement process of Ga2Te3 in BM-Ga2Te3/C. Thus, this study provides a new material development strategy of employing mechano- and electro-chemical nano-confinement processes to develop high-performance anodes for LIBs. [ABSTRACT FROM AUTHOR]

The capture, sequestration and utilization of carbon dioxide have attracted global attention in the environmental field, science and industry. The concurrent conversion of CO2 and CH4 is a reasonable solution to reduce greenhouse gases, but it remains a challenging research topic. Herein, we reveal the catalytic activity of bifunctional half-sandwich complexes (metal = Ru, Rh, and Ir) in the direct conversion of methane and carbon dioxide to acetic acid (AA) using density functional theory. The use of Ru/Rh/Ir metals with ethanediphosphine (PP), N-tosylethylenediamine (NNTs), and ethylene glycol (OO) ligands shows superb performance in lowering the free energy (ΔG) barrier (ΔG‡) for the conversion. To activate CH4 and CO2 molecules, we used extra additives to reduce the high energy barriers required by simple metal–ligand complexes. For CH4 activation, additives of AA and trifluoroacetic acid (TFA) were used to assist the proton abstraction in the Ru–NNTs/OO complexes, while no acid additives were used for the PP ligands. In the case of the PP ligands, the C–H activation occurs through a "concerted oxidative addition–reductive elimination" (OA–RE) process, whereas in the NNTs/OO ligands, C–H activation occurs through "cyclometallation deprotonation" (CMD) irrespective of the presence of acid additives. The reduction in ΔG‡ for CH4 activation in Ru–NNTs/OO is 5–10 kcal mol−1 using acid additives. In contrast, in Ru–PP, this ΔG‡ barrier is 20 kcal mol−1 without additives. For CO2 activation, AlCl3 (Lewis acid) was used to insert CO2 into the metal site of the Ru–NNTs/OO and Ru/Rh/Ir–PP complexes. The reduction in ΔG‡ using AlCl3 for CO2 activation in Ru–NNTs·AA/OO·2TFA and Ru/Rh/Ir–PP is 15–30 kcal mol−1. Then, the overall activation barrier is reduced to 20–27 kcal mol−1. [ABSTRACT FROM AUTHOR]

The development of recycling technology for waste glass is crucial because numerous types of waste glass are generated daily. To recycle waste glass, we developed a facile conversion technology for turning waste glass into high-capacity Li storage materials. Nanostructured Si-based composites were synthesized by a simple solid-state synthesis method using three waste glass types: soda-lime, borosilicate, and quartz. Firstly, various waste glass types were mechanically crushed into powders, after which they were reduced into Si using a Mg reducing agent powder by a simple high-energy ball-milling (BM) process, forming composites comprising Si and MgO (Si/MgO). The potentials of these composites for use as Li-ion battery (LIB) anodes were investigated. To further enhance the electrochemical performances of the Si/MgO composites, amorphous C-modified composites (Si/MgO/C) were simply prepared by further high-energy BM processing for 0.5 h. The Si/MgO/C composites comprised well-dispersed nanocrystalline Si, Li-inactive MgO, and various Li-inactive oxides from the additives used for glass formation within the buffering amorphous C matrices. The Si/MgO/C composites prepared by the facile recycling of waste borosilicate and quartz glasses exhibited high reversible capacities of 487 and 549 mA h g−1 and stable capacity retentions of approximately 100% and 93% after 200 cycles, respectively. [ABSTRACT FROM AUTHOR]

A layered germanium telluride (GeTe) and its C-modified nanocomposite (GeTe–C) are synthesized by a simple solid-state synthesis technique, and their electrochemical behaviors for rechargeable lithium-ion batteries (LIBs) are evaluated. Various ex situ analytical tools are employed to demonstrate the electrochemical Li-insertion/-extraction mechanisms of the electrodes. GeTe during Li-insertion exhibits two-step conversion/alloying reactions, and does not recombine after Li-extraction. Interestingly, although GeTe–C shows the same two-step conversion/alloying reactions during Li-insertion, Ge and Te fully recombine after Li-extraction. Owing to the full recombination reactions by the ongoing Li-cycling, GeTe–C shows excellent electrochemical Li-ion storage performances, such as highly reversible capacities (1st Li-insertion/-extraction capacity: 841/691 mA h g−1 or 1767/1450 mA h cm−3), extremely rigid cycling durability (capacity retention: 97.8% after 100 cycling), and rapid rate-capabilities (940 mA h cm−3 at 3C-rate). Therefore, the GeTe–C modified with layered GeTe and amorphous C is a promising anode material with a high energy density for high-performance LIBs. [ABSTRACT FROM AUTHOR]

This Feature Article introduces the preparation and synthetic utility of α-diazo oxime ethers. α-Oximino carbenes are useful synthons for N-heterocycles, and can be easily prepared from α-diazo oxime ethers as precursors. We begin with the preparation of α-diazo oxime ethers and their application in [3+2] cycloaddition. It turns out that the nature of metals bound to carbenes plays a crucial role in modulating the reactivity of α-oximino carbenes, in which copper carbenes smoothly react with enamines, whereas the less reactive enol ethers and nitriles require gold carbenes. In Section 3.2, a discussion on N–O and C–H bond activation is presented. Carbenes derived from diazo oxime ethers show unique reactivity towards N–O and C–H bond activation, in which the proximity of the two functionalities, carbene and oxime ether, dictates the preferred reaction pathways toward pyridines, pyrroles, and 2H-azirines. In Section 3.3, the development of tandem reactions based on α-diazo oxime ethers is discussed. The nature of carbenes in which whether free carbenes or metal complexes are involved dissects the pathway and forms different types of 2H-azirines. The 2H-azirine formation turned out to be an excellent platform for the tandem synthesis of N-heterocycles including pyrroles and pyridines. In the last section, we describe the electrophilic activation of 2H-azirines with vinyl carbenes and oximino carbenes. The resulting azirinium species undergo rapid ring expansion rearrangements to form pyridines and pyrazines. [ABSTRACT FROM AUTHOR]

Puckered-layer-structured germanium monosulfide (GeS) and corresponding amorphous-carbon-decorated nanocomposites (GeS–C) were synthesized and used to fabricate Li-ion battery anodes which displayed remarkable reversible capacity above 1050 mA h g−1 after 100 cycles. [ABSTRACT FROM AUTHOR]

An efficient synthetic method for carbazoles has been developed employing diazo anilinoalkynes as substrates. Sequential activation of the orthogonal functional groups embedded in diazo anilinoalkyne substrates by tandem gold–copper catalysis leads to the formation of highly substituted carbazoles. Substrate scope reveals a broad tolerability toward the substitution on aryl groups. [ABSTRACT FROM AUTHOR]

Here, we report, for the first time, the preparation of Sb2Te3 and the Sb2Te3/C nanocomposite by a simple solid-state synthetic route and their application as Li-ion battery anode materials. The nanocomposite showed an interesting reaction mechanism and outstanding electrochemical performance. [ABSTRACT FROM AUTHOR]

Cationic gold complexes of α-oximimino carbenes have been identified to react with weak nucleophiles including enol ethers and nitriles. These findings allowed us to develop the highly efficient synthesis of pyrroles and oxazoles. [ABSTRACT FROM AUTHOR]

Zinc telluride (ZnTe) and a nanostructured ZnTe/C composite were prepared by a simple solid-state synthetic route, and their potential as electrode materials for rechargeable Li-ion batteries was investigated. The electrochemical conversion/partial recombination reactions between ZnTe and Li were determined using ex situ X-ray diffraction and extended X-ray absorption fine structure analysis. X-ray diffraction and high-resolution transmission electron microscopy confirmed that the ZnTe/C nanocomposite consisted of ZnTe nanocrystallites that were uniformly distributed within an amorphous carbon matrix. The nanostructured ZnTe/C composite electrode exhibited excellent electrochemical properties with a high capacity (1st charge: 530 mA h g−1), cycling durability (over 200 cycles), and fast rate capability (1 C: ca. 550 mA h g−1, 3 C: ca. 504 mA h g−1). [ABSTRACT FROM AUTHOR]

Co-Sb intermetallic compounds (CoSb, CoSb2, and CoSb3) were simply synthesized by solid-state synthesis routes and their potential as anode materials for Li-ion batteries was investigated. The CoSb3 electrode showed poor electrochemical behavior, but the CoSb and CoSb2 electrodes showed relatively good electrochemical performance. Additionally, the reaction mechanisms of CoSb, CoSb2, and CoSb3 with Li were identified using ex situ X-ray diffraction. To improve the electrochemical performance of the Co-Sb intermetallic compounds, nanostructured composites of these compounds modified with carbon were prepared using a high-energy mechanical milling technique. Among the fabricated nanocomposites, the CoSb2/C nanocomposite electrode comprising disproportionated nanocrystalline CoSb, amorphous Sb, and an amorphous carbon matrix showed excellent electrochemical properties, such as a high energy density (1st charge: 578 mA h g-1, or ~2895 mA h cm-3), cycling durability over 100 cycles (above 490 mA h g-1, or ~2450 mA h cm-3), high initial Coulombic efficiency (~78.1%), and a fast rate capability (1 C: 472 mA h g-1, 3 C: 415 mA h g-1). These excellent electrochemical properties demonstrated by the CoSb2/C nanocomposite electrode confirm its potential as an alternative anode material for Li-ion batteries. [ABSTRACT FROM AUTHOR]

A simple, inexpensive, fast, and scalable method of transforming micron-sized metal oxides into new intermetallic compound nanocomposites by a hybrid mechanochemical synthesis using a high-energy mechanical milling technique was developed. The SnSb/MOx (M = Al or Mg)/C nanocomposites, synthesized by the mechanochemical reduction of SnO and Sb2O3 with Al or Mg, respectively, in the presence of carbon, were confirmed, by using various analytical techniques, to be composed of extremely small SnSb nanocrystallites, amorphous Al2O3 or nanocrystalline MgO, and amorphous carbon. Among the fabricated nanocomposites, the SnSb/MgO/C nanocomposite showed excellent electrochemical properties, such as a high energy density (1st charge: 572 mA h g−1 or ca. 3800 mA h cm−3), cycling durability (above 490 mA h g−1 or ca. 3300 mA h cm−3 over 150 cycles), good initial coulombic efficiency (ca. 81.3%), and a fast rate capability (1C: 480 mA h g−1, 3C: 420 mA h g−1). These excellent electrochemical properties demonstrated by the SnSb-based nanocomposite electrodes confirmed their potential as alternative anode materials for Li-ion batteries. [ABSTRACT FROM AUTHOR]

Li–air(O2) and Li–S batteries have gained much attention recently and most relevant research has aimed to improve the electrochemical performance of air(O2) or sulfur cathode materials. However, many technical problems associated with the Li metal anode have yet to be overcome. This review mainly focuses on the electrochemical behaviors and technical issues related to metallic Li anode materials as well as other metallic anode materials such as alkali (Na) and alkaline earth (Mg) metals, including Zn and Al when these metal anodes were employed for various types of secondary batteries. [ABSTRACT FROM AUTHOR]

Here, we report a simple, cheap, and rapid synthesis method combined with physical and chemical routes for porous structured metal-based carbon nanocomposites, which can be applicable to anode materials for high performance Li-ion batteries. [ABSTRACT FROM AUTHOR]

Control over chemo- and regioselectivity is a critical issue in the heterobiaryl synthesis via C-H oxidative coupling. To address this challenge, a strategy to invert the normal polarity of indoles in the heterobiaryl coupling was developed. With N -carboxyindoles as umpoled indoles, an exclusively ortho -selective coupling with phenols has been realized, employing a Brønsted acid- or Cu(i)-catalyst (as low as 0.01 mol%). A range of phenols and N -carboxyindoles coupled with exceptional efficiency and selectivity at ambient temperature and the substrates bearing redox-active aryl halides (-Br and -I) smoothly coupled in an orthogonal manner. Notably, preliminary examples of atropselective heterobiaryl coupling have been demonstrated, based on a chiral disulfonimide or a Cu(i)/chiral bisphosphine catalytic system. The reaction was proposed to occur through S N 2' substitution or a Cu(i)-Cu(iii) cycle, with Brønsted acid or Cu(i) catalysts, respectively., Competing Interests: The authors declare no conflict of interest., (This journal is © The Royal Society of Chemistry.)

We developed a proximity photo-crosslinking method ( Spotlight ) with a 4-azido- N -ethyl-1,8-naphthalimide (AzNP) moiety that can be converted to reactive aryl nitrene species using ambient blue light-emitting diode light. Using an AzNP-conjugated HaloTag ligand (VL1), blue light-induced photo-crosslinked products of various HaloTag-conjugated proteins of interest were detected in subcellular spaces in live cells. Chemical or heat stress-induced dynamic changes in the proteome were also detected, and photo-crosslinking in the mouse brain tissue was enabled. Using Spotlight , we further identified the host interactome of SARS-CoV-2 nucleocapsid (N) protein, which is essential for viral genome assembly. Mass analysis of the VL1-crosslinked product of N -HaloTag in HEK293T cells showed that RNA-binding proteins in stress granules were exclusively enriched in the cross-linked samples. These results tell that our method can reveal the interactome of protein of interest within a short distance in live cells., Competing Interests: The authors declare no competing interests., (This journal is © The Royal Society of Chemistry.)

Highly efficient synthesis of 3-hydroxypyridines has been developed based on carbenoid-mediated N-O bond insertion. Treatment of δ-diazo oxime ethers with dirhodium complex Rh(2)(tfacam)(4) rapidly provides a variety of pyridines in 5-10 minutes in good to excellent yields.

Free carbenes generated from α-diazo oxime ethers by photolysis undergo facile N-O insertion to afford 2-alkyl/aryloxy-2H-azirines in good to excellent yields. This method allowed for the development of a tandem reaction for pyrrole synthesis via 1,3-dipolar cycloaddition.

An efficient dual synthetic manifold for 2-aminofurans and 2-unsubstituted furans has been developed. The carbenoid-mediated [3 + 2] cycloaddition of copper carbenoids with enamines provides 2-amino-2,3-dihydrofurans which serve as common intermediates for both 2-aminofurans and 2-unsubstituted furans.

Mild catalytic reaction conditions for the synthesis of 2-isoxazolines and 2H-azirines have been developed via carbenoids derived from α-oximino diazo compounds. This has been utilized in the one-pot synthesis of pyrroles in the presence of 1,3-dicarbonyl compounds.