Weak-Interaction Environment in a Composite Electrolyte Enabling Ultralong-Cycling High-Voltage Solid-State Lithium Batteries.

Poly(vinylidene fluoride) (PVDF)-based solid electrolytes with a Li salt-polymer-little residual solvent configuration are promising candidates for solid-state batteries. Herein, we clarify the microstructure of PVDF-based composite electrolyte at the atomic level and demonstrate that the Li+-interaction environment determines both interfacial stability and ion-transport capability. The polymer works as a "solid diluent" and the filler realizes a uniform solvent distribution. We propose a universal strategy of constructing a weak-interaction environment by replacing the conventional N,N-dimethylformamide (DMF) solvent with the designed 2,2,2-trifluoroacetamide (TFA). The lower Li+ binding energy of TFA forms abundant aggregates to generate inorganic-rich interphases for interfacial compatibility. The weaker interactions of TFA with PVDF and filler achieve high ionic conductivity (7.0 × 10-4 S cm-1) of the electrolyte. The solid-state Li||LiNi0.8Co0.1Mn0.1O2 cells stably cycle 4900 and 3000 times with cutoff voltages of 4.3 and 4.5 V, respectively, as well as deliver superior stability at -20 to 45 °C and a high energy density of 300 Wh kg-1 in pouch cells.

Flexible Hydrazone-Linked Metal-Covalent Organic Frameworks with Copper Clusters for Efficient Electrocatalytic Oxygen Evolution Reaction.

Despite the challenges associated with the synthesis of flexible metal-covalent organic frameworks (MCOFs), these offer the unique advantage of maximizing the atomic utilization efficiency. However, the construction of flexible MCOFs with flexible building units or linkages has rarely been reported. In this study, novel flexible MCOFs are constructed using flexible building blocks and copper clusters with hydrazone linkages. The heterometallic frameworks (Cu, Co) are prepared through the hydrazone linkage coordination method and evaluated as catalysts for the oxygen evolution reaction (OER). Owing to the spatial separation and functional cooperation of the heterometallic MCOF catalysts, the as-synthesized MCOFs exhibited outstanding catalytic activities with an overpotential of 268.8 mV at 10 mA cm-2 for the OER in 1 M KOH, which is superior to those of the reported covalent organic frameworks (COFs)-based OER catalysts. Theoretical calculations further elucidated the synergistic effect of heterometallic active sites within the linkages and frameworks, contributing to the enhanced OER activity. This study thus introduces a novel approach to the fundamental design of flexible MCOF catalysts for the OER, emphasizing their enhanced atomic utilization efficiency.

Flexible wafer-scale bifunctional metasurface based on nanoimprinting.

Metasurfaces have demonstrated remarkable capabilities in manipulating light fields across diverse applications. However, current research tends to examine these functionalities in isolation, prompting a growing interest in integrating different functionalities within a singular metasurface device. In this paper, we propose and experimentally demonstrate a bifunctional metasurface capable of providing concealment and sensing functions simultaneously. Specifically, the proposed nanostructure effectively operates as a one-way mirror, exhibiting an average reflection rate of approximately 90% under external illumination, alongside an absorption rate of 87.9% from the opposite direction of incidence. This functionality renders it suitable for privacy-enhancing building windows. Meanwhile, this nanostructure also integrates liquid sensing capabilities boasting a sensitivity of 464 nm/RIU, which is particularly valuable for monitoring liquid-based corrosion. The experimental performance of the prepared 6-inch nanohole-patterned metasurface closely aligns with the simulations, and the utilization of flexible polyethylene terephthalate (PET) film, coupled with nanoimprint lithography technology, enables a direct and cost-effective manufacturing process that can be scaled up for widespread applications.

Prognosis of LSPD versus TIPS for the treatment of esophagogastric variceal bleeding in cirrhosis.

BACKGROUND: This study aimed to compare postoperative complications in patients with esophagogastric variceal bleeding (EVB) who underwent laparoscopic splenectomy combined with pericardial devascularization (LSPD) versus transjugular intrahepatic portosystemic shunt (TIPS) procedures. METHODS: A retrospective collection of medical records was conducted from January 2014 to May 2020 at Union Hospital, Tongji Medical College, Huazhong University of Science and Technology. The study included patients from the departments of trauma surgery, interventional radiology, and general surgery who were diagnosed with EVB caused by portal hypertension and treated with LSPD or TIPS. Follow-up data were obtained to assess the occurrence of postoperative complications in both groups. RESULTS: A total of 201 patients were included in the study, with 104 cases in the LSPD group and 97 cases in the TIPS group. There was no significant difference in the 1-year and 3-year post-surgery survival rates between the TIPS and LSPD groups (P = 0.669, 0.066). The 3-year survival rate of Child-Pugh B patients in the LSPD group was higher than TIPS group (P = 0.041). The LSPD group also had a significantly higher rate of freedom from rebleeding at 3-year post-surgery compared to the TIPS group (P = 0.038). Stratified analysis showed no statistically significant difference in the rebleeding rate between the two groups. Furthermore, the LSPD group had a higher rate of freedom from overt hepatic encephalopathy at 1-year and 3-year post-surgery compared to the TIPS group (P = 0.007, < 0.001). The LSPD group also had a lower rate of severe complications at 3-year post-surgery compared to the TIPS group (P = 0.020). CONCLUSION: Compared to TIPS, LSPD does not increase the risk of mortality and rebleeding, while demonstrating fewer complications. In patients classified as Child-Pugh A and B, the use of LSPD for treating EVB is both safe and effective.

Nobiletin alleviates atherosclerosis by inhibiting lipid uptake via the PPARG/CD36 pathway.

BACKGROUND: Atherosclerosis (AS) is a persistent inflammatory condition triggered and exacerbated by several factors including lipid accumulation, endothelial dysfunction and macrophages infiltration. Nobiletin (NOB) has been reported to alleviate atherosclerosis; however, the underlying mechanism remains incompletely understood. METHODS: This study involved comprehensive bioinformatic analysis, including multidatabase target prediction; GO and KEGG enrichment analyses for function and pathway exploration; DeepSite and AutoDock for drug binding site prediction; and CIBERSORT for immune cell involvement. In addition, target intervention was verified via cell scratch assays, oil red O staining, ELISA, flow cytometry, qRT‒PCR and Western blotting. In addition, by establishing a mouse model of AS, it was demonstrated that NOB attenuated lipid accumulation and the extent of atherosclerotic lesions. RESULTS: (1) Altogether, 141 potentially targetable genes were identified through which NOB could intervene in atherosclerosis. (2) Lipid and atherosclerosis, fluid shear stress and atherosclerosis may be the dominant pathways and potential mechanisms. (3) ALB, AKT1, CASP3 and 7 other genes were identified as the top 10 target genes. (4) Six genes, including PPARG, MMP9, SRC and 3 other genes, were related to the M0 fraction. (5) CD36 and PPARG were upregulated in atherosclerosis samples compared to the normal control. (6) By inhibiting lipid uptake in RAW264.7 cells, NOB prevents the formation of foam cell. (7) In RAW264.7 cells, the inhibitory effect of oxidized low-density lipoprotein on foam cells formation and lipid accumulation was closely associated with the PPARG signaling pathway. (8) In vivo validation showed that NOB significantly attenuated intra-arterial lipid accumulation and macrophage infiltration and reduced CD36 expression. CONCLUSIONS: Nobiletin alleviates atherosclerosis by inhibiting lipid uptake via the PPARG/CD36 pathway.

Research Progress on Active Ingredients and Product Development of Lycium ruthenicum Murray.

Lycium ruthenicum Murray possesses significant applications in both food and medicine, including antioxidative, anti-tumor, anti-fatigue, anti-inflammatory, and various other effects. Consequently, there has been a surge in research endeavors dedicated to exploring its potential benefits, necessitating the organization and synthesis of these findings. This article systematically reviews the extraction and content determination methods of active substances such as polysaccharides, anthocyanins, flavonoids, and polyphenols in LRM in the past five years, as well as some active ingredient composition determination methods, biological activities, and product development. This review is divided into three main parts: extraction and determination methods, their bioactivity, and product development. Building upon prior research, we also delve into the economic and medicinal value of Lycium ruthenicum Murray, thereby contributing significantly to its further exploration and development. It is anticipated that this comprehensive review will serve as a valuable resource for advancing research on Lycium ruthenicum Murray.

Elaborate Modulating Binding Strength of Intermediates via Three-component Covalent Organic Frameworks for CO2 Reduction Reaction.

The catalytic performance for electrocatalytic CO2 reduction reaction (CO2RR) depends on the binding strength of the reactants and intermediates. Covalent organic frameworks (COFs) have been adopted to catalyze CO2RR, and their binding abilities are tuned via constructing donor-acceptor (DA) systems. However, most DA COFs have single donor and acceptor units, which caused wide-range but lacking accuracy in modulating the binding strength of intermediates. More elaborate regulation of the interactions with intermediates are necessary and challenge to construct high-efficiency catalysts. Herein, the three-component COF with D-A-A units was first constructed by introducing electron-rich diarylamine unit, electron-deficient benzothiazole and Co-porphyrin units. Compared with two-component COFs, the designed COF exhibit elevated electronic conductivity, enhanced reducibility, high efficiency charge transfer, further improving the electrocatalytic CO2RR performance with the faradic efficiency of 97.2 % at -0.8 V and high activity with the partial current density of 27.85 mA cm-2 at -1.0 V which exceed other two-component COFs. Theoretical calculations demonstrate that catalytic sites in three-component COF have suitable binding ability of the intermediates, which are benefit for formation of *COOH and desorption of *CO. This work offers valuable insights for the advancement of multi-component COFs, enabling modulated charge transfer to improve the CO2RR activity.

Precisely Engineering Asymmetric Atomic CoN4 by Electron Donating and Extracting for Oxygen Reduction Reaction.

The development of nonpyrolytic catalysts featuring precisely defined active sites represents an effective strategy for investigating the fundamental relationship between the catalytic activity of oxygen reduction reaction (ORR) catalysts and their local coordination environments. In this study, we have synthesized a series of model electrocatalysts with well-defined CoN4 centers and nonplanar symmetric coordination structures. These catalysts were prepared by a sequential process involving the chelation of cobalt salts and 1,10-phenanthroline-based ligands with various substituent groups (phen(X), where X=OH, CH3, H, Br, Cl) onto covalent triazine frameworks (CTFs). By modulating the electron-donating or electron-withdrawing properties of the substituent groups on the phen-based ligands, the electron density surrounding the CoN4 centers was effectively controlled. Our results demonstrated a direct correlation between the catalytic activity of the CoN4 centers and the electron-donating ability of the substituent group on the phenanthroline ligands. Notably, the catalyst denoted as BCTF-Co-phen(OH), featuring the electron-donating OH group, exhibited the highest ORR catalytic activity. This custom-crafted catalyst achieved a remarkable half-wave potential of up to 0.80 V vs. RHE and an impressive turnover frequency (TOF) value of 47.4×10-3 Hz at 0.80 V vs. RHE in an alkaline environment.

High-Performance CMOS Inverter Array with Monolithic 3D Architecture Based on CVD-Grown n-MoS2 and p-MoTe2.

In this work, monolithic three-dimensional complementary metal oxide semiconductor (CMOS) inverter array has been fabricated, based on large-scale n-MoS2 and p-MoTe2 grown by the chemical vapor deposition method. In the CMOS device, the n- and p-channel field-effect transistors (FETs) stack vertically and share the same gate electrode. High k HfO2 is used as the gate dielectric. An Al2 O3 seed layer is used to protect the MoS2 from heavily n-doping in the later-on atomic layer deposition process. P-MoTe2 FET is intentionally designed as the upper layer. Because p-doping of MoTe2 results from oxygen and water in the air, this design can guarantee a higher hole density of MoTe2 . An HfO2 capping layer is employed to further balance the transfer curves of n- and p-channel FETs and improve the performance of the inverter. The typical gain and power consumption of the CMOS devices are about 4.2 and 0.11 nW, respectively, at VDD of 1 V. The statistical results show that the CMOS array is with high device yield (60%) and an average voltage gain value of about 3.6 at VDD of 1 V. This work demonstrates the advantage of two-dimensional semi-conductive transition metal dichalcogenides in fabricating high-density integrated circuits.

ATP7B gene therapy of autologous reprogrammed hepatocytes alleviates copper accumulation in a mouse model of Wilson's disease.

BACKGROUND AND AIMS: Wilson's disease (WD) is a rare hereditary disorder due to ATP7B gene mutation, causing pathologic copper storage mainly in the liver and neurological systems. Hepatocyte transplantation showed therapeutic potential; however, this strategy is often hindered by a shortage of quality donor cells and by allogeneic immune rejection. In this study, we aimed to evaluate the function and efficacy of autologous reprogrammed, ATP7B gene-restored hepatocytes using a mouse model of WD. APPROACH AND RESULTS: Sufficient liver progenitor cells (LPCs) were harvested by reprogramming hepatocytes from ATP7B-/- mice with small molecules, which exhibited strong proliferation and hepatic differentiation capacity in vitro. After lentivirus-mediated mini ATP7B gene transfection and redifferentiation, functional LPC-ATP7B-derived hepatocytes (LPC-ATP7B-Heps) were developed. RNA sequencing data showed that, compared with LPC-green fluorescent protein-Heps (LPC-GFP-Heps) with enrichment of genes that were mainly in pathways of oxidative stress and cell apoptosis, in LPC-ATP7B-Heps under high copper stress, copper ion binding and cell proliferation pathways were enriched. LPC-ATP7B-Heps transplantation into ATP7B-/- mice alleviated deposition of excess liver copper with its associated inflammation and fibrosis, comparable with those observed using normal primary hepatocytes at 4 months after transplantation. CONCLUSIONS: We established a system of autologous reprogrammed WD hepatocytes and achieved ATP7B gene therapy in vitro. LPC-ATP7B-Heps transplantation demonstrated therapeutic efficacy on copper homeostasis in a mouse model of WD.

Stable and reliable IGZO resistive switching device with HfAlOxinterfacial layer.

The performance stability of the resistive switching (RS) is vital for a resistive random-access memory device. Here, by inserting a thin HfAlOxlayer between the InGaZnO (IGZO) layer and the bottom Pt electrode, the RS performance in amorphous IGZO memory device is significantly improved. Comparing with a typical metal-insulator-metal structure, the device with HfAlOxlayer exhibits lower switching voltages, faster switching speeds, lower switching energy and lower power consumption. As well, the uniformity of switching voltage and resistance state is also improved. Furthermore, the device with HfAlOxlayer exhibits long retention time (>104s at 85 °C) , high on/off ratio and more than 103cycles of endurance at atmospheric environment. Those substantial improvements in IGZO memory device are attributed to the interface effects with a HfAlOxinsertion layer. With such layer, the formation and rupture locations of Ag conductive filaments are better regulated and confined, thus an improved performance stability.

Evaluating the Correlation of Hedgehog Pathway with Claudin-1 Expression in Invasive Breast Cancer.

Being a heterogeneous disease, breast cancer illustrates different biological and phenotypic features which make its diagnosis and treatment challenging. This study aimed to evaluate the expression levels of crucial components of the Hedgehog signaling pathway, the correlation between the signal transducer Smo, and clinicopathologic features (lymph node metastasis and metastasis stage) in invasive breast carcinoma. Besides, the inverse correlation was considered between expression levels of Smo and Claudin-1. For this purpose, in a case-control study, we evaluated 72 tumor and adjacent normal tissue specimens obtained from invasive ductal breast cancer patients. The expression levels of Hedgehog signaling components (Smo, Gli1, and Ptch), Claudin-1, E-cadherin, and MMP2 were measured by qRT-PCR. The correlations between Smo expressions with some clinicopathologic parameters were also analyzed. Compared to normal adjacent tissues, the results showed up-regulation of Hedgehog signaling in invasive breast carcinoma samples. Upregulation of the signal transducer Smo correlated with tumor stages and lymph node metastasis of the breast tumors. This correlation was affected by the expression of Her2. A significant correlation existed between expression levels of the signal transducer Smo and Claudin-1, E-cadherin as an epithelial cell marker, and MMP2 as a metastasis-related gene in advanced metastatic tumor samples. Based on the obtained results, a new layer of molecular complexity was found, which should be considered in managing patients with invasive breast carcinoma. The results suggested a key role for Hedgehog signaling in invasive breast carcinoma. In terms of the inverse correlation between expression levels of Claudin-1 and Hedgehog signaling, Claudin-1 could serve as a candidate gene in diagnostic studies. Thus, its clinical significance should be further clarified.

Theoretical study on hydrogen transfer in the dissociation of dimethyl disulfide radical cations.

Hydrogen transfer (HT) is of crucial importance in biochemistry and atmospheric chemistry. Here, HT processes involved in the dissociation reaction of dimethyl disulfide radical cations (DMDS˙+, CH3SSCH3˙+) are investigated using quantum chemical calculations. Four HTs from the C to S atom and one HT from the S to S atom are observed and the most probable paths are proposed in the dissociation channel from DMDS˙+ to CHnS+ (n = 2-4). The mechanisms of all these five HTs are described as hydrogen atom transfer (HAT) and four of them are accompanied by electron transfer (ET). Considering the catalytic effect of water molecules existing in organisms and the atmosphere, five HT processes in the dissociation of the [DMDS + H2O]˙+ complex are further explored, which show lower free energy barriers. With the participation of water molecules acting as a base, two HTs from the C to the S atom, which have the largest decrease in energy barriers, are characterized as concerted proton-coupled electron transfer (cPCET). These results can be extended to understand the mechanism of the HT process during the dissociation of disulfide and help provide a strategy to design a rare cPCET mechanism for the activation of the C-H bond.

Intestinal microbiota disturbance affects the occurrence of African swine fever.

Intestinal microbiota not only participates in the digestion and absorption of nutrients, but also plays an important role in regulating host metabolism and health. The current study aimed to explore the intestinal microbiota characteristics in pigs infected with African swine fever. Below the same term, fresh fecal samples of sick and healthy pigs were collected. Primers were designed and PCR was extracted based on the 16S rDNA gene of bacteria by Illumina NovaSeq sequencing platform. The results showed that the bacterial alpha diversity index of healthy pigs was significantly higher than that of sick pigs (p < 0.05). On the phylum taxa, dominant bacteria more than 98.5% in the two groups are composed of Firmicutes, Spirobacteria, and Bacteroides, of which the abundance of Firmicutes and Bacteroidetes decreased and Spiricobacteria increased extremely significant in sick pigs (p < 0.01). On the genus taxa, the relative abundance of Oscillospira, Streptococcus and Roseburia decreased significantly (p < 0.05). Most notably, Treponema performed excellently in distinguishing pigs infected with African swine fever with the abundance increased extremely significantly (p < 0.01). In conclusion, African swine fever could alter the abundance of dominant bacteria in pigs, and Treponema may be one of the important inducers for swine pathogenicity. HighlightsThe bacterial population composition in sick pigs and healthy pigs was basically similar, but the relative abundance of dominant bacteria was significantly difference.ASF could alter the abundance of dominant bacteria in pigs, and Treponema may be one of the important inducers for swine pathogenicity.These results will provide further evidence for the ASF infection in local pig farms and provide reference for their microecological control, which has important practical significance and social value for effective control of ASF, stability of pig production and guarantee of market supply.

Magnetic Phase Transitions and Magnetoelastic Coupling in a Two-Dimensional Stripy Antiferromagnet.

Materials with a quasi-one-dimensional stripy magnetic order often exhibit low crystal and magnetic symmetries, thus allowing the presence of various energy coupling terms and giving rise to macroscopic interplay between spin, charge, and phonon. In this work, we performed optical, electrical and magnetic characterizations combined with first-principles calculations on a van der Waals antiferromagnetic insulator chromium oxychloride (CrOCl). We detected the subtle phase transition behaviors of exfoliated CrOCl under varying temperature and magnetic field and clarified its controversial spin structures. We found that the antiferromagnetism and its air stability persist down to few-layer samples, making it a promising candidate for future 2D spintronic devices. Additionally, we verified the magnetoelastic coupling effect in CrOCl, allowing for the potential manipulation of the magnetic states via electric field or strain. These virtues of CrOCl provide us with an ideal platform for fundamental research on spin-charge, spin-phonon coupling, and spin-interactions.

Study on Fluorescence Recognition of Fe3+, Cr2O72- and p-Nitrophenol by a Cadmium Complex and Related Mechanism.

The effective detection of environmental pollutants is very important to the sustainable development of human health and the environment. A luminescent Cd(II) coordination complex, {[Cd(dbtdb)(1,2,4-H3btc)]·0.5H2O}n (1) (dbtdb = 1-(2,3,5,6-tetramethyl-4-((2-(thiazol-4-yl)-2H-benzo[d]imidazol-3(3aH)-yl)methyl)benzyl)-2,7a-dihydro-2-(thiazol-4-yl)-1H-benzo[d]imidazole, 1,2,4-H3btc = 1,2,4-benzenetricarboxylic acid), was obtained by hydrothermal reactions. Complex 1 has a chain structure decorated with uncoordinated Lewis basic O and S donors and provides good sensing of Fe3+, Cr2O72-, and p-nitrophenol with fluorescence quenching through an energy transfer process. The calculated binding constants were 3.3 × 103 mol-1 for Fe3+, 2.36 × 104 mol-1 for Cr2O72-, and 9.3 × 103 mol-1 for p-nitrophenol, respectively. These results show that 1 is a rare multiresponsive sensory material for efficient detection of Fe3+, Cr2O72-, and p-nitrophenol.

Spatial distribution characteristics and risk assessment of soil heavy metal pollution around typical coal gangue hill located in Fengfeng Mining area.

The pollution of heavy metals in soil caused by exposed coal gangue and its prevention and control has become a hot issue restricting the green mining of coal in China. Nemerow integrated pollution index (NIPI), potential ecological risk index (RI) and human health risk assessment model were used to evaluate the pollution and risk of heavy metals (Cu, Cr, As, Pb) in the soil around the typical coal gangue hill in Fengfeng mining area of China. The results show that: firstly, the accumulation of coal gangue leads to the enrichment of four heavy metals in the surrounding shallow soil, and NIPI and RI were 1.0-4.4 and 21.63-91.28, respectively. The comprehensive pollution level of heavy metals in soil reached the warning line and above, and the potential ecological risk level reached slightly and above. When the horizontal distance exceeded 300 m, 300 m and 200 m, respectively, the influence of coal gangue hill on the heavy metal content in shallow soil, the comprehensive pollution level of heavy metals and the potential ecological risk level basically disappeared. In addition, based on the potential ecological risk assessment results and main risk factors, the ecological risk configuration of the study area was divided into five categories: "strong ecological risk + As," "intermediate ecological risk + As + Cu," "intermediate ecological risk + As + Cu or Pb," "minor ecological risk + As + Cu" and "minor ecological risk + As + Cu or Pb." The hazard index (HI) and total carcinogenic risk (TCR) of shallow soil polluted by heavy metals in the study area were 0.24-1.07 and 0.41 × 10-4-1.78 × 10-4, respectively, which posed non-carcinogenic and carcinogenic risks to children, but the risks were controllable. This study will help to take strategic measures to accurately control and repair the heavy metal pollution in the soil around the coal gangue hill and provide a scientific basis for solving the safe use of agricultural land and realizing the construction of ecological civilization.

[Latest Findings on Polyketides/Non-ribosomal Peptides That Are Secondary Metabolites of Streptococcus mutans].

Dental caries is a chronic infectious disease that occurs in the hard tissue of teeth under the influence of multiple factors, among which bacteria being a key factor. Streptococcus mutans ( S. mutans) is considered a major pathogen that causes caries. Secondary metabolites, including bacteriocins and polyketides/non-ribosomal peptides, are a class of small-molecule compounds synthesized by S. mutans. To date, polyketides/non-ribosomal peptides identified in S. mutans include mutanobactin, mutanocyclin, and mutanofactin, which are synthesized by the mub, muc, and muf biosynthetic gene clusters, respectively. These polyketides/non-ribosomal peptides play important roles in bacterial inter-species competition, oxidative stress, and biofilm formation. In this review, we provided an overview of the synthesis, function and regulation of three polyketides/non-ribosomal peptides of S. mutans, including mutanobactin, mutanocyclin, and mutanofactin, aiming to provide new insights into the cariogenic mechanism of S. mutans and to promote the better management of dental caries.

One-Dimensional Covalent Organic Frameworks for the 2e- Oxygen Reduction Reaction.

Two-dimensional covalent organic frameworks (2D COFs) are often employed for electrocatalytic systems because of their structural diversity. However, the efficiency of atom utilization is still in need of improvement, because the catalytic centers are located in the basal layers and it is difficult for the electrolytes to access them. Herein, we demonstrate the use of 1D COFs for the 2e- oxygen reduction reaction (ORR). The use of different four-connectivity blocks resulted in the prepared 1D COFs displaying good crystallinity, high surface areas, and excellent chemical stability. The more exposed catalytic sites resulted in the 1D COFs showing large electrochemically active surface areas, 4.8-fold of that of a control 2D COF, and thus enabled catalysis of the ORR with a higher H2 O2 selectivity of 85.8 % and activity, with a TOF value of 0.051 s-1 at 0.2 V, than a 2D COF (72.9 % and 0.032 s-1 ). This work paves the way for the development of COFs with low dimensions for electrocatalysis.

CoN5 Sites Constructed by Anchoring Co Porphyrins on Vinylene-Linked Covalent Organic Frameworks for Electroreduction of Carbon Dioxide.

Developing effective electrocatalysts for CO2 reduction (CO2 RR) is of critical importance for producing carbon-neutral fuels. Covalent organic frameworks (COFs) are an ideal platform for constructing catalysts toward CO2 RR, because of their controllable skeletons and ordered pores. However, most of these COFs are synthesized from Co-porphyrins or phthalocyanines-based monomers, and the available building units and resulting catalytic centers in COFs are still limited. Herein, Co-N5 sites are first developed through anchoring Co porphyrins on an olefin-linked COF, where the Co active sites are uniformly distributed in the hexagonal networks. The strong electronic coupling between Co porphyrins and COF is disclosed by various characterizations such as X-ray absorption spectroscopy (XAS) and density functional theory calculation (DFT). Thanks to the CoN5 sites, the catalytic COF shows remarkable catalytic activity with Faraday efficiencies (FECO ) of 84.2-94.3% at applied potentials between -0.50 and -0.80 V (vs RHE), and achieves a turnover frequency of 4578 h-1 at -1.0 V. Moreover, the theoretical calculation further reveals that the CoN5 sites enable a decrease in the overpotential for the formation COOH*. This work provides a design strategy to employ COFs as scaffold for fabricating efficient CO2 electrocatalysts.