Strategies that enable simultaneous morphology‐tuning and electroreduction performance boosting are much desired for the exploration of covalent organic frameworks in efficient CO2 electroreduction. ...Herein, a kind of functionalizing exfoliation agent has been selected to simultaneously modify and exfoliate bulk COFs into functional nanosheets and investigate their CO2 electroreduction performance. The obtained nanosheets (Cu−Tph−COF−Dct) with large‐scale (≈1.0 μm) and ultrathin (≈3.8 nm) morphology enable a superior FECH4 (≈80 %) (almost doubly enhanced than bare COF) with large current‐density (−220.0 mA cm−2) at −0.9 V. The boosted performance can be ascribed to the immobilized functionalizing exfoliation agent (Dct groups) with integrated amino and triazine groups that strengthen CO2 absorption/activation, stabilize intermediates and enrich the CO concentration around the Cu active sites as revealed by DFT calculations. The point‐to‐point functionalization strategy for modularly assembling Dct‐functionalized COF catalyst for CO2 electroreduction will open up the attractive possibility of developing COFs as efficient CO2RR electrocatalysts.
A kind of functionalizing exfoliation agent has been selected to simultaneously modify and exfoliate bulk COFs into functional nanosheets and the obtained materials can be applied in highly selective CO2 electroreduction into CH4.
The exploration of novel systems for the electrochemical CO2 reduction reaction (CO2RR) for the production of hydrocarbons like CH4 remains a giant challenge. Well‐designed electrocatalysts with ...advantages like proton generation/transferring and intermediate‐fixating for efficient CO2RR are much preferred yet largely unexplored. In this work, a kind of Cu‐porphyrin‐based large‐scale (≈1.5 μm) and ultrathin nanosheet (≈5 nm) has been successfully applied in electrochemical CO2RR. It exhibits a superior FECH4
of 70 % with a high current density (−183.0 mA cm−2) at −1.6 V under rarely reported neutral conditions and maintains FECH4
>51 % over a wide potential range (−1.5 to −1.7 V) in a flow cell. The high performance can be attributed to the construction of numerous hydrogen‐bonding networks through the integration of diaminotriazine with Cu‐porphyrin, which is beneficial for proton migration and intermediate stabilization, as supported by DFT calculations. This work paves a new way in exploring hydrogen‐bonding‐based materials as efficient CO2RR catalysts.
A Cu‐porphyrin‐based large‐scale, ultrathin nanosheet with numerous hydrogen‐bonding networks was developed for the highly selective electroreduction of CO2 to CH4 under neutral conditions. This catalyst exhibits a superior FECH4
of 70 % with a high current density (−183.0 mA cm−2) at −1.6 V under rarely reported neutral conditions and maintains FECH4
>51 % over a wide potential range (−1.5 to −1.7 V) in a flow cell.
The selective photo‐oxidation of biomass‐derived 5‐hydroxymethylfurfural (HMF) to 2,5‐furandicarboxylic acid (FDCA) is important due to its substitute‐role in polyester‐fabrication. Here, a ...titanium‐cluster based metal‐covalent organic framework nanosheet has been synthesized through the covalent‐coupling between Ti6‐NH2 and benzotrithiophene tricarbaldehyde (BTT). The integration of them endows the nanosheet with a visible‐light‐adsorption region, effective electron‐hole separation‐efficiency and suitable photo‐oxidation ability. Specifically, its photo‐selectivity for HMF‐to‐FDCA can be >95 % with ≈100 % conversion, which is more than 2, 5, and 10 times higher than MOF‐901 (43 %), Ti6‐NH2 (19 %) and under‐darkness (9 %), respectively. Notably, an O2‐based mechanism is proposed and the vital roles of Ti6‐NH2 and BTT are verified by DFT calculations. This work might facilitate the exploration of porous‐crystalline‐catalysts for selective biomass‐valorization.
A titanium‐cluster‐based metal‐covalent organic framework nanosheet has been prepared through the covalent‐coupling between the Ti‐cluster and an oxidation group. The resulting nanosheets can be applied for highly selective photo‐oxidation of biomass HMF into FDCA.
The elaborate design of powerful Li–S binders with extended‐functions like polysulfides adsorption/catalysis and Li+ hopping/transferring in addition to robust adhesion‐property has remained a ...challenge. Here, an in situ cathode‐interweaving strategy based on metalloporphyrin based covalent‐bonding organic polymer (M‐COP, M = Mn, Ni, and Zn) binders is reported for the first time. Thus‐produced functional binders possess excellent mechanical‐strengths, polysulfides adsorption/catalysis, and Li+ hopping/transferring ability. Specifically, the modulus of Mn‐COP can reach up to ≈54.60 GPa (≈40 times higher than poly(vinylidene fluoride)) and the relative cell delivers a high initial‐capacity (1027 mAh g‐1, 1 C and 913 mAh g‐1, 2 C), and excellent cycling‐stability for >1000 cycles even at 4 C. The utilization‐rate of sulfur can reach up to 81.8% and the electrodes based on these powerful binders can be easily scale‐up fabricated (≈20 cm in a batch‐experiment). Noteworthy, Mn‐COP based cell delivers excellent capacities at a high sulfur‐loading (8.6 mg cm‐2) and low E/S ratio (5.8 µL mg‐1). In addition, theoretical calculations reveal the vital roles of metalloporphyrin and thiourea‐groups in enhancing the battery‐performance.
An in situ cathode‐interweaving strategy based on metalloporphyrin organic polymer (M‐COP, M = Mn, Ni, and Zn) binders is proposed and excellent performance is achieved in Li–S battery.
Porous heterostructured electrocatalysts with multifunctionality and synergistic effect have much benefit for efficient electrocatalytic CO2 reduction reaction (CO2RR), yet it still remains a ...daunting challenge to explore heterostructures based on covalent organic frameworks (COFs) and metal–organic frameworks (MOFs) in this field. Here, a series of honeycomb‐like porous crystalline hetero‐electrocatalysts (MCH‐X, X = 1–4, X stands for the numbered sample obtained from different MOF doses in the synthesis of the MCH) are synthesized, and these are successfully applied in electrocatalytic CO2RR. The specially designed heterostructures with integrated porous MOF‐template and ultrathin COF‐coating enable efficient CO2 adsorption/activation and conversion into CH4. The best of them, MCH‐3, shows greatly inhibited H2 evolution, excellent current density (−398.1 mA cm−2), and superior FECH4${\rm{F}}{{\rm{E}}_{{\rm{C}}{{\rm{H}}_4}}}$ (76.7%) to the physical mixture (38.0%), the MOF@COF without the honeycomb‐like morphology (47.7%), and the bare COF (37.5%) and MOF (15.9%) at −1.0 V. Based on the density functional theory calculations and various characterizations, the vital roles of the MOF in facilitating CO2 adsorption/activation, stabilizing intermediates, and conquering the energy barrier of rate‐determining step are intensively studied.
A series of honeycomb‐like metal–organic framework (MOF)@covalent organic framework (COF) heterostructures with integrated porous MOF template and ultrathin COF coating are synthesized and successfully applied in efficient CO2 electroreduction to CH4.
As a parasitic protozoan, Plasmodium falciparum (P. falciparum) can cause malaria. The mitochondrial proteins of malaria parasite play important roles in the discovery of anti-malarial drug targets. ...Thus, accurate identification of mitochondrial proteins of malaria parasite is a key step for understanding their functions and finding potential drug targets. In this work, we developed a sequence-based method to identify the mitochondrial proteins of malaria parasite. At first, we extended adjoining dipeptide composition to g-gap dipeptide composition for discretely formulating the protein sequences. Subsequently, the analysis of variance (ANOVA) combined with incremental feature selection (IFS) was used to pick out the optimal features. Finally, the jackknife cross-validation was used to evaluate the performance of the proposed model. Evaluation results showed that the maximum accuracy of 97.1 % could be achieved by using 101 optimal 5-gap dipeptides. The comparison with previous methods demonstrated that our method was accurate and efficient.
The relationship between Helicobacter pylori (H. pylori) infection and nonalcoholic fatty liver disease (NAFLD) is a matter of debate. Although it has been studied in many observational studies, the ...results remain controversial. Therefore, we performed a meta-analysis to assess the association between H pylori infection and risk of NAFLD.
We searched Pubmed, EMBASE, and Web of Science databases, from inception to September 10, 2020. Odds ratio (OR) and 95% confidence interval (CI) were pooled by random-effects model. The statistical heterogeneity among studies (I2-index), subgroup analyses, regression analyses, sensitivity analysis and the possibility of publication bias were assessed.
A total of seventeen studies involving 91,958 individuals were included in our meta-analysis. Meta-analysis of data from cross-sectional and case-control studies showed that H pylori infection was associated with increased risk of prevalent NAFLD (n = 15; involving 74,561 middle-aged individuals; OR1.38, 95% CI 1.23-1.55, I2 = 86.8%, P < .001). The results of meta-regression implicated that the study type and the case-control ratio impacted the total effect size. Funnel plot did not show significant publication bias. Meta-analysis of data from longitudinal studies showed that H pylori infection was also associated with increased NAFLD incidence (n = 2; involving 17397 individuals; OR 1.21, 95% CI 1.01-1.44, I2 = 6.5%, P = .301).
The results indicated that a positive association between H pylori infection and the risk of NAFLD. Further studies are required to strengthen the association and clarify the mechanism.
Strategy that can design powerful photothermal‐catalysts to achieve photothermal‐effect assisted coupling‐catalysis is much desired for the improvement of energy conversion efficiency and redox ...product value in CO2 electroreduction system. Herein, a kind of bifunctional viologen‐containing covalent organic framework (Ni‐2CBpy2+‐COF) has been prepared and successfully applied in photothermal‐assisted co‐electrolysis of CO2 and methanol. Specifically, the FECO (cathode) and FEHCOOH (anode) for Ni‐2CBpy2+‐COF can reach up to ≈100 % at 1.9 V with ≈31.5 % saved overall electricity‐consumption when the anodic oxygen evolution reaction (OER) is replaced by methanol oxidation. The superior performance could be attributed to the cyclic diquats in Ni‐2CBpy2+‐COF that enhance the photothermal effect (ΔT=49.1 °C) to accelerate faster charge transfer between catalyst and immediate species as well as higher selectivity towards desired products as revealed by DFT calculations and characterizations.
A kind of bifunctional viologen‐containing covalent‐organic‐framework has been prepared and successfully applied in photothermal‐assisted co‐electrolysis of CO2 and methanol. The superior performance could be attributed to the cyclic diquats in Ni‐2CBpy2+‐COF that enhance the photothermal effect to accelerate faster charge‐transfer between catalyst and immediate species as well as higher selectivity towards desired products.
Exploring efficient and inexpensive oxygen evolution reaction (OER) electrocatalysts is of great importance for various electrochemical energy storage and conversion technologies. Ni-based ...electrocatalysts have been actively pursued because of their promising activity and earth abundance. However, the OER efficiency for most of the developed Ni-based electrocatalysts has been intrinsically limited due to their low electrical conductivity and poor active site exposure yield. Herein, we report metallic Ni3N nanosheets as an efficient OER electrocatalyst for the first time. The first-principles calculations and electrical transport property measurements unravel that the Ni3N is intrinsically metallic, and the carrier concentration can be remarkably improved with dimensional confinement. The EXAFS spectra provide solid evidence that the Ni3N nanosheets have disordered structure resultant of dimensional reduction, which then could provide more active sites for OER. Benefiting from enhanced electrical conductivity with metallic behavior and atomically disordered structure, the Ni3N nanosheets realize intrinsically improved OER activity compared with bulk Ni3N and NiO nanosheets. Our finding suggests that metallic nitride nanosheets could serve as a new group of OER electrocatalysts with excellent property.
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