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A self-supporting MOF-based electrode was prepared via a facile semi-sacrificial anodic electrodeposition strategy, which exhibited improved mass/charge transport and active site accessibility, enhancing urea oxidation-coupled water electrolysis.

Enterocytozoon hepatopenaei(EHP) is a shrimp pathogen that causes huge economic losses. In the present study, the hosts of EHP were investigated using polymerase chain reaction (PCR) in an aquaculture farm located in Maoming, China. EHP was detected inLitopenaeus vannamei,Penaeus monodon, crab, false mussel, and three dragonfly species (Anax parthenope,Pantala flavescens, andIschnura senegalensis). In the histopathological examination using hematoxylin–eosin staining, EHP spores were found in nymphs and adult dragonflies naturally infected with EHP that were collected from the shrimp farm. Fluorescence in situ hybridization results showed a positive signal for EHP infection in the fat body of dragonfly nymphs. Immature and mature microsporidian spores and late sporogonial plasmodium were observed in the cytoplasm of dragonfly nymphs using transmission electron microscopy. The transmission of EHP from shrimp to dragonfly nymphs was confirmed via cohabitation challenge experiments in which EHP-free dragonfly nymphs were cohabited with EHP-infected shrimp, and the transmission of EHP from dragonfly nymphs to shrimp was demonstrated via the cohabitation of EHP-infected dragonfly nymphs with EHP-free shrimp and oral administration challenge experiments. This study confirms that dragonflies can act as natural EHP hosts, and a novel EHP horizontal transmission route exists between dragonflies and shrimp.Author summaryTo the authors’ knowledge, this study presents the first report of microsporidia (EHP) infecting both crustaceans and insects (A. parthenope,P. flavescens, andI. senegalensis). The horizontal transmission of EHP between dragonfly nymphs and shrimp was confirmed through cohabitation and oral administration challenge experiments. EHP has become a globally significant threat to shrimp aquaculture. The findings of the present study will help to design prevention strategies, such as the use of nets to prevent dragonflies from entering shrimp ponds.

Core–shell Bi38O44/45@TixL-oxo clusters were prepared by the stepwise assembly from soluble Bi38O45@Ti6 precursors to show modifiable shell and reversible structure transformation, which further changed their chemical fixation activities of CO2.

The effects of different human walking patterns on contaminant dispersion in residential kitchens were investigated through computational fluid dynamics simulation with the dynamic mesh method. A tracer gas experiment was performed to verify the feasibility and accuracy of the simulation method. Flow characteristics induced by human walking were minutely described, and the transient capture efficiency of the range hood was adopted to assess the impact of human walking quantitatively. Human walking parallel to a counter, human walking parallel to a counter manned by another human, and human walking toward a counter were studied. Results showed that the mutual effect of the wake and thermal plume caused contaminant dispersion and decreased the performance of the range hood as the human subject walked beside the counter. Even a standing person operated ahead the counter, the wake would affect the thermal plume in a certain extent. The decrement of capture efficiency approached 0.5 in the most unfavorable situation. Moreover, the coaction of the positive/negative pressure zone and impinging air jet drew the thermal plume to the human body. The fluctuation of capture efficiency in this condition was moderate relative to that for the human walking pattern beside the counter. This research could provide a comprehensive overview of different human walking patterns and their impact on residential kitchens and thereby facilitate the maintenance of kitchen air quality.

Central flues are now commonly adopted in high-rise residential buildings in China for cooking oil fumes (COF) exhaust. Range hoods of all floors are connected to the central shaft, where oil fumes were gathered and exhausted through the outlet at the building roof. As households may cook and use their range hood at random periods, there is great uncertainty of the amount of COF being exhausted. In addition, users can often adjust the exhaust rate of the range hood according to their needs. As a result, thousands of possible operating conditions consisting of distinct combinations of on/off conditions and fan speed occur randomly in the central COF exhaust system, causing the exhaust performance to vary considerably from condition to condition. This work developed a mathematical model for characterizing the operation of the central COF exhaust system in a high-rise residential building as well as its iterative solving method. Full-scale tests coupled with CFD simulation referring to a real 30-floor building were conducted to validate the proposed model. The results show that the model agreed well with the CFD and experimental data under various system operating conditions. Moreover, the Monte-Carlo method was introduced to simulate the random operating characteristics of the system, and a hundred thousand cases corresponding to distinct system operating conditions were sampled and statistically analyzed.

An electrocatalytic carbon dioxide reduction reaction (CO2RR) is an appealing route to obtain the value-added feedstocks and alleviate the energy crisis. However, how to achieve high-performance electrocatalysts for CO2 reduction to formate is challenging owing to the poor intrinsic activity, insufficient conductivity, and low surface density of active sites. Herein, we fabricated an extremely active and selective hydrangea-like superstructured micro/nanoreactor of ultrathin bismuth nanosheets through an in situ electrochemical topotactic transformation of hierarchical bismuth oxide formate (BiOCOOH). The resulted bismuth nanosheet superstructure is in the form of three-dimensional intercrossed networks of ultrathin nanosheets, forming an ordered open porous structure through self-assembly, which can be used as a micro/nanoreactor to enable a large electrochemically active surface area as well as high atomic utilization. Such a distinctive nanostructure endows the material with high electrocatalytic performances for CO2 reduction to formate with near-unity Faradaic selectivity (>95%) in a wide potential window from -0.78 to -1.18 V. Furthermore, this micro/nanoreactor can give the high current densities over 300 mA cm-2 at low applied potentials without compromising selectivity in a flow cell reactor. Density functional theory (DFT) and in situ attenuated total reflection-infrared spectroscopy (in situ ATR-IR) were further conducted to interpret the CO2RR mechanisms.

The conversion of CO2 into value-added chemicals through the electrocatalytic CO2 reduction reaction (CO2RR) is considered as an up-and-coming way to facilitate the renewable closed carbon cycle and energy storage. Therefore, the development of robust and low-cost CO2RR electrocatalysts is essential but challenging. Herein, a Ni single-atom catalyst (Ni–SAs–NC) was successfully prepared via a precursor assembly strategy and a subsequent one-step pyrolysis process. Characterization studies demonstrate that abundant Ni single-atom active sites with the coordination structure of Ni–N4 are uniformly dispersed in Ni–SAs–NC, which consequently endow it with outstanding electrocatalytic CO2RR performance. Strikingly, the as-prepared Ni–SAs–NC can selectively convert CO2 into CO with a high faradaic efficiency of up to 98%, and can maintain the high values exceeding 90% in a wide potential range from −0.6 to −1.0 V. This work provides a new protocol to prepare high-efficiency but low-cost single-atom electrocatalysts toward the CO2RR and other electrochemical reactions.

Herein, for the first time, an active and stable bifunctional electrocatalyst has been elaborately designed to achieve the integration of CO2 reduction and anodic non-classical reaction to efficiently yield products of high value at both electrodes, which was constructed by surface anchoring of a novel multi-azido-group-bearing nickel phthalocyanine onto carbon nanotubes at the single-molecule level via strong interactions. Concretely, the obtained heterojunction-type electrocatalyst exhibits ultrahigh activity for completely selective CO2-to-CO conversion with a 100% faradaic efficiency in a wide potential window, large partial current density (>200 mA cm−2) and turnover frequency, and remarkable stability. Particularly, a mass of azido-derived amine groups around the nickel phthalocyanine centers increase the local concentration of CO2via chemisorption, thus boosting the formation of the key intermediate. Unprecedentedly, an exotic electrolytic system integrating CO2 reduction with oxidative nano-polymerization was further conceptually developed using this individual bifunctional electrocatalyst for both the cathode and anode. Besides the high-performance CO2 reduction at the cathode, a unique porous 3D polymer nano-framework was obtained in the anode chamber instead of low-value O2, while the cell voltage was significantly reduced by 1.05 V to achieve 10 mA cm−2.

Bismuth (Bi)-based nanomaterials are considered as promising electrocatalysts for the electrocatalytic CO2 reduction reaction (CO2RR), but it is still challenging to achieve high current density and selectivity in a wide potential window. Herein, Cu-decorated Bi/Bi2O3 nanofoam (P–Cu–BiNF) with a 3D porous network structure was prepared for the first time via a simple fast-reduction method. Characterizations indicate that the introduction of Cu can significantly regulate the microstructure and electronic states of Bi/Bi2O3. Consequently, the as-prepared P–Cu–BiNF exhibits excellent electrocatalytic performance toward the CO2RR. Remarkably, the faradaic efficiency of formate production can exceed 90% in a wide potential range from −0.78 to −1.08 V. Meanwhile, it can also deliver a high formate partial current density of up to 62.7 mA cm−2 at −1.18 V and long-term stability. This work provides a simple but effective way to synthesize advanced Bi-based materials with significantly improved electrocatalytic CO2RR performance.

Transition metal-based single-atom catalysts (TM-SACs) are promising alternatives to Au- and Ag-based electrocatalysts for CO production through CO 2 reduction reaction. However, developing TM-SACs with high activity and selectivity at low overpotentials is challenging. Herein, a novel Fe-based SAC with Si doping (Fe-N-C-Si) was prepared, which shows a record-high electrocatalytic performance toward the CO 2 -to-CO conversion with exceptional current density (>350.0 mA cm −2 ) and ~100% Faradaic efficiency (FE) at the overpotential of 2 battery delivers an outstanding performance with a maximal power density of 2.44 mW cm −2 at an output voltage of 0.30 V, as well as high cycling stability and FE (>90%) for CO production. Experimental combined with theoretical analysis unraveled that the nearby Si dopants in the form of Si-C/N bonds modulate the electronic structure of the atomic Fe sites in Fe-N-C-Si to markedly accelerate the key pathway involving *CO intermediate desorption, inhibiting the poisoning of the Fe sites under high CO coverage and thus boosting the CO 2 RR performance. This work provides an efficient strategy to tune the adsorption/desorption behaviors of intermediates on single-atom sites to improve their electrocatalytic performance.

This paper proposes a push-pull airflow combined with a top draft hood to conduct local exhaust in a rubber workshop. Field measurements are carried out to investigate the characteristics of the emission source, while numerical simulation is performed based on the measurement to test the capture efficiency and to further optimize various parameters including push velocity, hood height and exhaust air rate. Compared with the high-hanging hood, the low-hanging hood can effectively capture the pollutant generated by tyre with lower exhaust air rate. The capture efficiency of the low-hanging hood reaches 98.18% with exhaust air rate of 6000 m3/h and push air velocity of 5m/s. The results indicates that the new ventilation appliance can effectively collect the pollutant at a relatively low exhaust rate.

The utilization of diphenyl sulfoxides as versatile electrophilic coupling partners for the Suzuki–Miyaura reaction via C–S bond cleavage was successfully developed under palladium-N-heterocyclic carbene catalysis. The reactions showed good functional group compatibility, proceeded well under mild conditions, and provided biaryls in yields of up to 96%. A wide range of useful functional groups, such as fluoro, chloro, ether, hydroxyl, amide, cyano, keto, trimethylsilyl (TMS), and ester were tolerated under the reaction conditions; however, the use of phenylboronic anhydride and arylboronic acid pinacol esters generally would lead low yields. Good regioselectivity for the electron-poor phenyl group was achieved when unsymmetrical diphenyl sulfoxides were used. The protocol is applicable at the gram scale even with half the amount of catalyst. Density functional theory calculations were performed to investigate the reaction mechanism, indicating that the reaction occurred through oxidative addition, transmetalation, and reductive elimination to provide the final coupling product.

Electrochemical reduction of CO2 to valuable fuels is appealing for CO2 fixation and energy storage. However, the development of electrocatalysts with high activity and selectivity in a wide potential window is challenging. Herein, atomically thin bismuthene (Bi-ene) is pioneeringly obtained by an in situ electrochemical transformation from ultrathin bismuth-based metal-organic layers. The few-layer Bi-ene, which possesses a great mass of exposed active sites with high intrinsic activity, has a high selectivity (ca. 100 %), large partial current density, and quite good stability in a potential window exceeding 0.35 V toward formate production. It even deliver current densities that exceed 300.0 mA cm-2 without compromising selectivity in a flow-cell reactor. Using in situ ATR-IR spectra and DFT analysis, a reaction mechanism involving HCO3- for formate generation was unveiled, which brings new fundamental understanding of CO2 reduction.

Self-supporting ultrathin FeNi-layered double hydroxide nanosheet arrays with atomically dispersed Cr atoms were firstly fabricated from stainless steel mesh by a facile ligand-assisted capping growth approach. Their unique nanostructure and a strong synergetic effect between the atomically dispersed Cr dopants and the active sites afford an exceptional OER activity.

Herein, we report the stepwise assembly and reversible transformation of atomically precise ligated titanium coated bismuth-oxide core nanostructures. The soluble and stable Bi

An electrocatalytic carbon dioxide reduction reaction (CO

In our previous studies, fluorine-substituted carbazoles were synthesized, and these compounds showed promising potential against Gram-positive bacterial stains, including Methicillin-resistant Staphylococcus aureus. However, only three compounds with two F substituents on the 2,4-positions of carbazole showed antibacterial potency against both Gram-positive and Gram-negative bacterial strains. A series of new compounds with two F substituents on the 2,4-positions of carbazole, besides three known ones, were synthesized. The structures were confirmed by infrared spectroscopy, 1H & 13C nuclear magnetic resonance spectroscopy, and high-resolution mass spectrometry. Eight compounds showed antibacterial activity. 2,4,6-Trifluoro-9H-carbazole (2), with simple structure, showed potential antibacterial activity against the multidrug resistant NDM-1-producing strains which are not inhibited by commonly used antibiotics. Its water-soluble salt was synthesized but showed less activity.

A protocol for C(sp)–C(sp2) bond formation via the Sonogashira coupling reaction involving C–N bond cleavage with aryltrimethylammonium triflate as an electrophilic coupling partner is described in...

Electrosynthesis of formic acid/formate is a promising alternative protocol to industrial processes. Herein, a pioneering pair-electrosynthesis tactic is reported for exclusively producing formate via coupling selectively electrocatalytic methanol oxidation reaction (MOR) and CO2 reduction reaction (CO2 RR), in which the electrode derived from Ni-based metal-organic framework (Ni-MOF) nanosheet arrays (Ni-NF-Af), as well as the Bi-MOF-derived ultrathin bismuthenes (Bi-enes), both obtained through an in situ electrochemical conversion process, are used as efficient anodic and cathodic electrocatalysts, respectively, achieving concurrent yielding of the same high-value product at both electrodes with greatly reduced energy input. The as-prepared Ni-NF-Af only needs quite low potentials to reach large current densities (e.g., 100 mA cm-2 @1.345 V) with ≈100% selectivity for anodic methanol-to-formate conversion. Meanwhile, for CO2 RR in the cathode, the as-prepared Bi-enes can simultaneously exhibit near-unity selectivity, large current densities, and good stability in a wide potential window toward formate production. Consequently, the coupled MOR//CO2 RR system based on the distinctive MOF-derived catalysts displays excellent performance for pair-electrosynthesis of formate, delivering high current densities and nearly 100% selectivity for formate production in both the anode and the cathode. This work provides a novel way to design advanced MOF-derived electrocatalysts and innovative electrolytic systems for electrochemical production of value-added feedstocks.

The discharge capacity of the range hood for cooking-related pollution under current exhaust airflow rate (EAR) standard of 300–500 m 3 /h is limited when cooking temperature near the smoke point of edible oil. This study endeavored to determine appropriate EAR for cooking temperature varies from 200 to 300 °C, which comprised smoke points of different edible oils, considering whether the kitchen was ventilated with the adjacent room or not, and the cooking position of the left/right stove. Particles generated from a simplified cooking process of oil heating test, tracer gas experiment, and flow visualization experiment were conducted. CFD simulation with capture efficiency as an evaluation index was performed. Evidence is presented that when the cooking temperature is 200 °C, the pollutant control effect does not change much when the EAR is above 700 m 3/h, while an EAR of 800 m3 /h may be necessary at 300 °C. For open-door and closed-door cooking, a minimal difference exists in demand for a suitable EAR in this local ventilation system . However, the hood continues to exhaust air during post-cooking period, thereby showing that a higher EAR is necessary to control the pollutants in open-door cooking. The primary and secondary cross draft airflows caused by different air supply positions are observed, which play a vital role in selecting suitable left/right cooking position. The location of the left stove is conducive to the elimination of cooking-related pollutants due to primary cross draft, while it is the right stove due to secondary cross draft.

Electrochemical reduction of CO

Range hood is a common ventilation appliance applied in a kitchen for maintaining healthy environment. This paper numerically studied the effect of air curtain on capture performance of a range hood, which was equipped in a residential kitchen chamber of 3.5 m * 2.7 m * 2.4 m. Two key parameters of air curtain, air-supply velocity and angle were investigated for improving the capture performance with CFD methods. Only when both the air-supply velocity and angle were well defined simultaneously, could the range hood have a good capture performance. When air-supply angle is 4°, air-supply velocity is recommended at 2.0–2.5 m/s. When air-supply velocity is 4.5 m/s, air-supply angle is recommended at 10°–14°. In the above situation, the range hood has better capture performance. The findings showed that the air curtain with reasonable air-supply velocity and angle could effectively improve the capture performance of range hood and protect the cook.

A series of new chiral-bridged N-heterocyclic carbene ligands with different substituents and their corresponding palladium complexes have been synthesised. The effect of the substituents on the catalytic activity of these Pd complexes was investigated in the Suzuki reaction of p-bromotoluene with phenylboronic acid, and the results showed that the complexes with aryl substituents performed better than those with alkyl substituents. The complex with the most sterically hindered substituent (diisopropyl on a phenyl group) performed best, and it was also an efficient catalyst for the reaction of various arylboronic acids with aryl halides having different electronic and steric properties. In addition, it was employed as a catalyst in the asymmetric Suzuki reaction, but only moderate yields of 1,1-binaphthalenes with less than 20% enantiomeric excess were obtained.

This study proposed a novel integrated design combing an air cleaner with the conventional exhaust hood for the improvement of indoor air quality in the residential kitchen. Airflow interaction between the exhaust confluence of the range hood and the strong momentum induced by air cleaner was investigated for this kind of compact configuration. The potential of energy saving by using the air cleaner was discussed. Firstly, numerical simulation was employed to obtain well-organized recirculation purification parameters under different air outlet widths and angles and experiments were conducted to verify the control effect of pollutant concentration in the kitchen space with the good design. Results show that the oblique upward air supply of the air cleaner was found significantly better to clean the kitchen space than horizontal and oblique downward supply. The relative purification effect of the integrated air cleaner is less affected by the exhaust flowrate of the hood. The PM 2.5 concentration reduction rate by the air cleaner at the breathing zone is near 60%, while the TVOC concentration reduction approximately 30%. Secondly, concentration decay rate at post-cooking period with/without the integrated air cleaner was measured and compared. It was found that the concentration decay rate achieved by the integrated air cleaner with 100 m3/h and oblique upward air supply is close to the decay rate of exhaust hood with 200 m3/h. It means that the integrated design proposed in this study is effective in reducing human exposure to cooking-related pollutants and has a significant energy-saving potential.

The function of air curtain range hood in improving human exposure was investigated by conducting experiment and CFD simulation. The intake fraction was estimated to reflect the effect of the air curtain. Factors affecting human exposure, including the exhaust rate, heat source intensity, air supply angle, air supply velocity, and slot width of the air curtain, were incorporated according to an orthogonal design. To comprehend the roles that the air curtain performed, the characteristics of flow and concentration field were captured through visualization experiment and CFD method. Furthermore, the effect of using an air curtain to resist the impact of human walking on human exposure was examined. The exhaust rate, heat source intensity, and air supply angle were significant factors that affect human exposure with a significance level of 0.01. Compared with the traditional range counterpart, air curtain range hood could decrease the intake fraction by factor of 1.5–5. Air curtain could reduce turbulent intensity around the range hood and improve local airflow organization. Meanwhile, air curtain would considerably protect walking humans from exposure to pollutants. The outcome of this study could help us understand the effect of air curtain range hood with a comprehensive perspective.