A built‐in electric field in electrocatalyst can significantly accumulate higher concentration of NO3− ions near electrocatalyst surface region, thus facilitating mass transfer for efficient nitrate ...removal at ultra‐low concentration and electroreduction reaction (NO3RR). A model electrocatalyst is created by stacking CuCl (111) and rutile TiO2 (110) layers together, in which a built‐in electric field induced from the electron transfer from TiO2 to CuCl (CuCl_BEF) is successfully formed . This built‐in electric field effectively triggers interfacial accumulation of NO3− ions around the electrocatalyst. The electric field also raises the energy of key reaction intermediate *NO to lower the energy barrier of the rate determining step. A NH3 product selectivity of 98.6 %, a low NO2− production of <0.6 %, and mass‐specific ammonia production rate of 64.4 h−1 is achieved, which are all the best among studies reported at 100 mg L−1 of nitrate concentration to date.
An electrocatalyst is created by stacking CuCl (111) and rutile TiO2 (110) layers together. A built‐in electric field induced from the electron transfer from TiO2 to CuCl (CuCl_BEF) is thus formed, which triggers interfacial accumulation of NO3− ions around the electrocatalyst. A NH3 product selectivity of 98.6 %, a low NO2− production of <0.6 %, and mass‐specific ammonia production rate of 64.4 h−1 is achieved.
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Nitrate electrocatalytic reduction (NO3RR) for ammonia production is a promising strategy to close the N‐cycle from nitration contamination, as well as an alternative to the Haber–Bosch process with ...less energy consumption and carbon dioxide release. However, current long‐term stability of NO3RR catalysts is usually tens of hours, far from the requirements for industrialization. Here, symmetry‐broken Cusingle‐atom catalysts are designed, and the catalytic activity is retained after operation for more than 2000 h, while an average ammonia production rate of 27.84 mg h−1 cm−2 at an industrial level current density of 366 mA cm−2 is achieved, obtaining a good balance between catalytic activity and long‐term stability. Coordination symmetry breaking is achieved by embedding one Cu atom in graphene nanosheets with two N and two O atoms in the cis‐configuration, effectively lowering the coordination symmetry, rendering the active site more polar, and accumulating more NO3− near the electrocatalyst surface. Additionally, the cis‐coordination splits the Cu 3d orbitals, which generates an orbital‐symmetry‐matched π‐complex of the key intermediate *ONH and reduces the energy barrier, compared with the σ‐complex generated with other catalysts. These results reveal the critical role of coordination symmetry in single‐atom catalysts, prompting the design of more coordination‐symmetry‐broken electrocatalysts toward possible industrialization.
A coordination‐symmetry‐breaking Cusingle‐atom catalyst enables a good balance between catalytic activity and long‐term stability in nitrate electroreduction to ammonia. The catalytic activity is retained after operation for more than 2000 h, while an average ammonia production rate of 27.84 mg h−1 cm−2 at an industrial level current density of 366 mA cm−2 is achieved.
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The first enantioselective construction of a new class of axially chiral naphthyl‐indole skeletons has been established by organocatalytic asymmetric coupling reactions of 2‐naphthols with ...2‐indolylmethanols (up to 99 % yield, 97:3 e.r.). This approach not only affords a new type of axially chiral heterobiaryl backbone, but also provides a new catalytic enantioselective strategy for constructing axially chiral biaryl scaffolds by making use of the C3‐electrophilicity of 2‐indolylmethanols.
Axed: The title compounds have been accessed by organocatalytic asymmetric coupling reactions of 2‐naphthols with 2‐indolylmethanols. This approach not only affords a new type of axially chiral heterobiaryl backbone, but also provides a new catalytic enantioselective strategy for constructing axially chiral biaryl scaffolds by making use of the C3‐electrophilicity of 2‐indolylmethanols. CPA=chiral phosphoric acid, M.S.=molecular sieves.
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Western-style diets arouse neuroinflammation and impair emotional and cognitive behavior in humans and animals. Our previous study showed that a high-fructose diet caused the hippocampal ...neuroinflammatory response and neuronal loss in animals, but the underlying mechanisms remained elusive. Here, alterations in the gut microbiota and intestinal epithelial barrier were investigated as the causes of hippocampal neuroinflammation induced by high-fructose diet.
A high-fructose diet caused the hippocampal neuroinflammatory response, reactive gliosis, and neuronal loss in C57BL/6N mice. Depletion of the gut microbiota using broad-spectrum antibiotics suppressed the hippocampal neuroinflammatory response in fructose-fed mice, but these animals still exhibited neuronal loss. Gut microbiota compositional alteration, short-chain fatty acids (SCFAs) reduction, intestinal epithelial barrier impairment, NOD-like receptor family pyrin domain-containing 6 (NLRP6) inflammasome dysfunction, high levels of serum endotoxin, and FITC-dextran were observed in fructose-fed mice. Of note, SCFAs, as well as pioglitazone (a selective peroxisome proliferator-activated receptor gamma (PPAR-γ) agonist), shaped the gut microbiota and ameliorated intestinal epithelial barrier impairment and NLRP6 inflammasome dysfunction in fructose-fed mice. Moreover, SCFAs-mediated NLRP6 inflammasome activation was inhibited by histamine (a bacterial metabolite) in ex vivo colonic explants and suppressed in murine CT26 colon carcinoma cells transfected with NLRP6 siRNA. However, pioglitazone and GW9662 (a PPAR-γ antagonist) exerted no impact on SCFAs-mediated NLRP6 inflammasome activation in ex vivo colonic explants, suggesting that SCFAs may stimulate NLRP6 inflammasome independently of PPAR-γ activation. SCFAs and pioglitazone prevented fructose-induced hippocampal neuroinflammatory response and neuronal loss in mice. Additionally, SCFAs activated colonic NLRP6 inflammasome and increased DCX
newborn neurons in the hippocampal DG of control mice.
Our findings reveal that gut dysbiosis is a critical factor for a high-fructose diet-induced hippocampal neuroinflammation in C57BL/6N mice possibly mediated by impairing intestinal epithelial barrier. Mechanistically, the defective colonic NLRP6 inflammasome is responsible for intestinal epithelial barrier impairment. SCFAs can stimulate NLRP6 inflammasome and ameliorate the impairment of intestinal epithelial barrier, resulting in the protection against a high-fructose diet-induced hippocampal neuroinflammation and neuronal loss. This study addresses a gap in the understanding of neuronal injury associated with Western-style diets. A new intervention strategy for reducing the risk of neurodegenerative diseases through SCFAs supplementation or dietary fiber consumption is emphasized.
The first catalytic asymmetric 2+3 cyclization of azlactones with azonaphthalenes has been established. This strategy allowed the synthesis of a variety of chiral isatin derivatives in generally good ...yields and excellent enantioselectivities (up to 99 % yield, 98 % ee). The developed reaction has not only established a catalytic enantioselective 2+3 cyclization using azlactones as two‐carbon building blocks, but also enriches the chemistry of catalytic asymmetric cyclizations of azonaphthalenes. In addition, this protocol will provide a useful method for constructing enantioenriched 3,3′‐disubstituted isatin‐type frameworks.
The surrogate: The catalytic asymmetric 2+3 cyclization of azlactones with azonaphthalenes has been established by using azlactones as two‐carbon building blocks and azonaphthalenes as 1,3‐dipole surrogates. This strategy allowed the synthesis of a variety of chiral isatin derivatives in generally good yields and excellent enantioselectivities. CPA=chiral phosphoric acid.
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Conjugated coordination polymers have become an emerging category of redox‐active materials. Although recent studies heavily focus on the tailoring of metal centers in the complexes to achieve stable ...electrochemical performance, the effect on different substitutions of the bridging bonds has rarely been studied. An innovative tailoring strategy is presented toward the enhancement of the capacity storage and the stability of metal–organic conjugated coordination polymers. Two nanostructured d‐π conjugated compounds, NiC6H2(NH)4n (Ni‐NH) and NiC6H2(NH)2S2n (Ni‐S), are evaluated and demonstrated to exhibit hybrid electrochemical processes. In particular, Ni‐S delivers a high reversible capacity of 1164 mAh g−1, an ultralong stability up to 1500 cycles, and a fully recharge ability in 67 s. This tailoring strategy provides a guideline to design future effective conjugated coordination‐polymer‐based electrodes.
An innovative tailoring strategy toward the enhancement of the capacity storage and stability of d‐π metal‐organic conjugated coordination polymers is proposed. The tailored compound Ni‐S shows a high reversible capacity of 1164 mAh g−1, an ultralong stability up to 1500 cycles, and a fully recharge ability of only 67 s.
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Construction of contiguous all‐carbon quaternary stereogenic centers is a long‐standing challenge in synthetic organic chemistry. In this report, a phosphine‐catalyzed enantioselective (3+2) ...annulation reaction between allenes and isoindigos, containing either two identical or different oxindole moieties, is introduced as a powerful strategy for the construction of spirocyclic bisindoline alkaloid core structures. The reported reactions feature high chemical yields, excellent enantioselectivities, and very good regioselectivities, and are highly useful for creating structurally challenging bisindoline natural products.
Strategic move: The phosphine‐catalyzed enantioselective (3+2) annulation reaction between allenes and isoindigos is introduced as a powerful strategy for the construction of structural motifs containing two vicinal quaternary stereogenic centers. The reactions feature high yields, enantioselectivities, and regioselectivities, and are highly useful for creating structurally challenging hexahydropyrroloindoles (HPIs).
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The sense of it: A new type of rapid, sensitive, and specific photoluminescence (PL)‐based assay has been proposed for the detection of phosphate (Pi) based on the competition of oxygen‐donor atoms ...from Pi with those from the carboxylate groups on a graphene‐quantum‐dot (GQD) surface for Eu3+ ions (see scheme). The graphene‐like structures combined with QD‐like optical properties suggest the promising nature of the GQDs as versatile tools in the fields of analytical science and biotechnology.
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It is discovered that the molecular packing and the orientation of crystallite arrangement in the film state are critical to the performance of the typical sandwich organic‐based memory devices ...(OMDs). Here, a solvent‐vapor annealing (SVA) strategy is firstly developed for amphipathic molecules to regulate the film morphology and intermolecular stacking, so as to obtain the satisfied performance. Through the screening of SVA solvents, an evidently upgraded nonvolatile memory behavior based on MeOH‐annealed film with superior reproducibility, a low switching voltage of −2.3 V and high ON/OFF ratio of 104 are observed. This work not only gives a fresh application of the amphipathic materials to OMDs, but really provides a general guiding significance for SVA solvent selection to achieve controllable crystallite orientation and effective OMDs performance.
A solvent‐vapor annealing (SVA) technique combined with amphipathic (AP) materials, are firstly proposed to fabricate organic memory devices (OMDs). It is found that the AP‐based films being exposed in MeOH saturated vapor exhibit better orientated molecular stacking and high‐quality nanopatterns, which is responsible for the upgraded performances. This result deepens the comprehension of SVA solvents section and the application of AP‐based devices.
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Knowledge distillation aims to compress a powerful yet cumbersome teacher model into a lightweight student model without much sacrifice of performance. For this purpose, various approaches have been ...proposed over the past few years, generally with elaborately designed knowledge rep-resentations, which in turn increase the difficulty of model development and interpretation. In contrast, we empirically show that a simple knowledge distillation technique is enough to significantly narrow down the teacher-student performance gap. We directly reuse the discriminative classifier from the pre-trained teacher model for student inference and train a student encoder through feature alignment with a single ℓ 2 loss. In this way, the student model is able to achieve exactly the same performance as the teacher model provided that their extracted features are perfectly aligned. An additional projector is developed to help the student encoder match with the teacher classifier, which renders our technique applicable to various teacher and student architectures. Extensive experiments demonstrate that our technique achieves state-of-the-art results at the modest cost of compression ratio due to the added projector.
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