A novel organic/inorganic S-scheme heterostructure of TCPP/Bi12O17Cl2 is successfully constructed. Taking the advantages of the strengthened visible-light response, effective spatial disintegration ...and conservation of highly energetic photo-carriers, this photosystem demonstrates a significant reinforcement of the photo-activity and stability towards the removal of antibiotics.
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•An S-scheme heterojunction of organic/inorganic TCPP/Bi12O17Cl2 was designed.•Effective spatial disintegration of powerful photo-carriers and optimized solar harvesting were achieved.•Remarkably reinforced photocatalytic performance was attained.•The tetracycline degradation pathway and the bio-toxicity of intermediates were unclosed.
The exploration of environment-friendly and efficacious materials with eminent photocatalytic efficacy is critical for the elimination of pharmaceutical antibiotics. Herein, a visible-light-driven organic–inorganic S-scheme heterostructure of meso-tetra (4-carboxyphenyl) porphyrin (TCPP)/Bi12O17Cl2, aiming to wipe out the antibiotic in wastewater, is developed via a simple approach. The TCPP is anchored on the surface of Bi12O17Cl2 to create the S-scheme junction between TCPP and Bi12O17Cl2, which strengthens visible-light response and expedites the spatial disintegration and conservation of photo-carriers with high redox capacity, therefore leading to a significant reinforcement of the photo-activity and stability. The champion TCPP/Bi12O17Cl2 manifests the best photo-degradation efficiency of 79.4% with the photoreaction rate constant of 0.0125 min−1 for tetracycline elimination, being 2.6 folds that of Bi12O17Cl2. The involved crucial reactive radicals, photo-degradation pathway and mechanism, and the eco-toxicity of intermediates over TCPP/Bi12O17Cl2 were elucidated through scavenging tests, LC-MS analysis, and toxicity calculation. This research illustrates the potential practicability on the rational design of porphyrin-based S-scheme heterojunction photocatalysts for efficient antibiotic removal.
Semiclathrate hydrates are host–guest materials that can be used for CO2 capture due to their unique gas selectivity. CO2 capture from H2 + CO2 mixed gas is possible by semiclathrate hydrates formed ...by tetra-n-butylammonium (TBA) and tetra-n-butylphosphonium (TBP) salts. TBA bromide (TBAB), TBA chloride (TBAC), TBP bromide (TBPB) and TBP chloride (TBPC) are widely available ionic substances for semiclathrate hydrate formation. In order to understand their gas capture properties, phase equilibrium data of these materials are necessary. Here we report experimental three phase (gas–hydrate–aqueous phase) equilibrium data measured in (TBAB, TBAC, TBPB or TBPC) + H2 + CO2 + H2O systems. The comparison with the literature data suggested that H2 can be incorporated in the TBAB and TBAC hydrates together with CO2, but TBPB and TBPC hydrates reject H2. The hydrate phases were identified by single crystal X-ray diffraction analyses. The TBAB, TBPB and TBPC form the same or similar hydrate phases, i.e., orthorhombic and hexagonal phases. The TBAC formed the tetragonal hydrate phase. The present results suggest that different CO2 capture properties are obtained by these semiclathrate hydrates.
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Medical sealant devices for in vivo hemostasis are far from satisfactory in the aged society. A major challenge is effective integration of quick hemorrhage control of the increased anticoagulated ...patients, high safety, and facile accessibility. Here, a well‐defined ammonolysis‐based Tetra‐PEG hydrogel sealant is developed with rapid gelation speed, strong tissue adhesion, and high mechanical strength. Introduction of cyclized succinyl ester groups into a hydrogel matrix endows the sealant with fast degradable and controllably dissolvable properties. The hydrogel possesses outstanding hemostatic capabilities even under the anticoagulated conditions while displaying excellent biocompatibility and feasibility. These results reveal that the optimized hydrogel may be a facile, effective, and safe sealant for hemorrhage control in vivo.
A PEG sealant with fast and controllable degradation properties is constructed for in vivo visceral organ hemostasis, which possesses high hemostatic efficacy even under anticoagulated situations and which, even more remarkably, does not hinder the tissue healing and cause side effects.
Primordial germ cells (PGCs) constitute an important cell lineage that directly impacts genetic dissemination and species conservation through the creation of cryobanks. In order to advance the field ...of animal genetic cryopreservation, this work aimed to recover intact PGCs cryopreserved in embryonic tissues during the segmentation phase for subsequent in vitro maintenance, using the yellow-tailed tetra (Astyanax altiparanae) as a model organism. For this, a total of 202 embryos were distributed in two experiments. In the first experiment, embryos in the segmentation phase were dissociated, and isolated PGCs were maintained in vitro. They were visualized using gfp-Pm-ddx4 3′UTR labeling. The second experiment aimed to vitrify PGCs using 3 cryoprotective agents or CPAs (dimethyl sulfoxide, ethylene glycol, and 1,2 propanediol) at 3 molarities (2, 3, and 4 M). The toxicity, somatic cell viability, and recovery of intact PGCs were evaluated. After cryopreservation and thawing, 2 M ethylene glycol produced intact PGCs and somatic cells (44 ± 11.52 % and 42.35 ± 0.33 %, respectively) post-thaw. The recovery of PGCs from frozen embryonic tissues was not possible without the use of CPAs. Thus, the vitrification of PGCs from an important developmental model and Neotropical species such as A. altiparanae was achieved, and the process of isolating and maintaining PGCs in a culture medium was successful. Therefore, to ensure the maintenance of genetic diversity, PGCs obtained during embryonic development in the segmentation phase between 25 and 28 somites were stored through vitrification for future applications in the reconstitution of species through germinal chimerism.
Tetra-tert-butyl-3-chloro-1-hydroxydistannoxane has been found to selectively cleave with high efficiency primary acetates on complex oligosaccharides containing esterified l-iduronic acid and ...bearing an anomeric acetate. This tin based catalyst was found much more effective than magnesium methoxide to carry out selective deacetylation.
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•Efficient selective deacetylation using organotin catalyst.
Top views and side views of the buckled tetra-SiC models before (a) and after (b) optimizing. The blue atoms are C, and the orange atoms are Si.
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Formation and atomic structure of ...two-dimensional (2D) tetra-SiC (containing entirely tetragons) are studied by molecular dynamics (MD) simulations. Models contain 6400 atoms (3200 Si atoms and 3200 C ones) interacted via so-called Vashishta’s interatomic potentials. We compress initially perfect planar SiC with honeycomb structure (hexa-SiC) at three different temperatures (below and above melting point) step by step and we find hexa-tetra 2D SiC phase transition. Tetra-SiC sample obtained at temperature significantly below melting point exhibits the best quality which contains the lowest concentration of defects (non-tetragons). This tetra-SiC is stable over a wide range of density and temperature. On the other hand, we cool the obtained tetra-SiC to room temperature and it is also stable at room temperature. Evolution of various structural and thermodynamic quantities upon compression is studied and we find that it exhibits a first-order-like phase transition behavior. Detailed analysis of structure of the obtained tetra-SiC is shown via coordination number and bond-angle distributions, ring statistics, 2D visualization of atomic configurations etc. Moreover, important quantities of mechanical behaviors such as Young modulus and Poisson’s ratio of the sample are found and discussed. DFT calculations show that flat tetra-SiC is stable with a band gap of around 0.97 eV. Our prediction of the existence of this new allotrope of 2D SiC can serve as a guide for further investigation in this direction including fabrication of material in practice.
Further improving mechanical performances of the tetra‐PEG hydrogel and simultaneously endowing it with functionalities remains a challenge. Herein, rGO is introduced into the tetra‐PEG network to ...construct a tetra‐PEG/rGO nanocomposite (NC) hydrogel with improved mechanical performances and functionalities. The hydrogel is prepared by in situ simultaneous polymerization of clickable tetra‐PEG macromonomers (TAPEG and TPPEG) and reduction of GO in one pot. The amount of rGO introduced into the hydrogel network is determined and can be controlled through tuning the feed ratio of the GO to the macromonomers. The tetra‐PEG/rGO NC hydrogel displays drastically improved mechanical performances including tensile properties, compressive properties, and fatigue resistance compared to the pristine clickable tetra‐PEG hydrogel. SEM, FT‐IR, and loading–unloading experiments indicate that interactions between rGO sheets and tetra‐PEG segments contribute to the mechanical improvement. Furthermore, the tetra‐PEG/rGO NC hydrogel exhibits selective dye adsorption ability and near‐infrared light responsiveness. The tetra‐PEG/rGO NC hydrogel with excellent mechanical performances and functionalities is highly promising in many areas such as dye absorption, remote light‐controlled devices, and tissue engineering.
In this work, a novel tetra‐PEG/rGO nanocomposite hydrogel is prepared through simultaneously gelating and reducing GO suspensions containing clickable tetra‐PEG macromonomers in one pot. Herein, the introduction of rGO into the tetra‐PEG network endows the tetra‐PEG/rGO nanocomposite hydrogel with improved mechanical performances and functionalities (selective dye adsorption ability and near‐infrared light responsiveness).
Formation of confined tetra-silicene (t-silicene) from the melt is studied by molecular dynamics (MD) simulation. Models containing 6066 atoms interacted via Stillinger-Weber potential are obtained ...by cooling from 5000 K to 300 K. We find that t-silicene is formed with the broad buckling distribution ranged from 0.60 Å to 1.49 Å differed from unique buckling of 1.49 Å predicted by DFT calculations. Depending on the cooling rate used in simulations one can obtain crystalline or amorphous samples. Crystallization and glass transition temperatures are defined, namely, TX≈1950 K and Tg≈1350 K. These temperatures are higher than those found for hexa-silicene. Structural characteristics of models are studied in details via radial distribution functions (RDFs), coordination number, bond-angle, interatomic distance and buckling distributions plus ring statistics. In addition, 2D visualization of atomic configurations plus diffraction pattern of the models at 300 K is done in order to see in more details structure of the models. Main types of structural defects are defined and their role in chemico-physical performance of t-silicene is discussed. Although main structural units are tetragons, both amorphous and crystalline t-silicenes contain many rings differed from tetragons. According to our calculations, the Poisson ratio for the obtained t-silicene is positive. In order to clarify interatomic potential effects on the formation of t-silicene, the same simulation procedure is done with the reactive force field and intensive comparison is given.
Oxygen and nitrogen-rich functional groups which are generally present in carbon materials may significantly affect their catalytic properties. The development of O, N-rich functional carbon ...materials with a simplified and low-budget strategy is of great importance for practical application. Herein, we describe a facile and straightforward method to prepare high contents of nitrogen and oxygen-rich carbon derived from ethylenediamine tetra-acetic acid tetra-sodium salt (Na4EDTA) by one-step carbonization in muffle furnace without inert gas protection. Compared with the carbon (EC-N700) synthesized in an argon atmosphere, the carbon (EC-A700) synthesized in an air-rich condition was more conducive to the formation of edge defects and topological defects and possessed higher contents of N and O elements. Consequently, the O, N-rich carbon EC-A700 was used as an efficient support of palladium nanoparticles toward catalytic formic acid dehydrogenation and nitroarene reduction. The catalyst Pd/EC-A700 achieved outstanding activity for formic acid dehydrogenation with a turnover frequency (TOF) up to 7039 h−1 at 60 °C. At the same time, the obtained catalyst Pd/EC-A700 also demonstrated exceptional catalytic performance in the 4-nitrophenol (4-NP) reduction with corresponding rate constant k of 0.72 min−1 under mild reaction conditions, which proved that the prepared catalyst Pd/EC-A700 has potentially applied in catalytic hydrogenation. This low-cost and simple approach breaks the tradition in mind that pyrolysis should always operate under inert conditions and provides a straightforward route to construct O, N-rich carbon as appealing materials for a wide variety of applications.
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•Break the tradition in mind and synthesize the O, N-rich carbon matrix.•One-step carbonation in aerobic conditions without any complicated treatments.•Abundant nitrogen/oxygen species benefited small size and dispersion of Pd NPs.•Good performance for formic acid dehydrogenation and 4-nitrophenol reduction.
● Structural and thermodynamical properties of semi-clathrate hydrate are summarized. ● Properties of quaternary salts and gas mixture hydrate are summarized. ● Challenges persist in the application ...of semi-clathrate hydrates for carbon capture and separation.
CO 2 is considered as the main contributor to global warming, and hydrate enclathration is an efficient way for carbon capture and separation (CCS). Semi-clathrate hydrate (SCH) is a type of clathrate hydrate capable of encaging CO 2 molecules under mild temperature and pressure conditions. SCH has numerous unique advantages, including high thermal stability, selective absorption of gas molecules with proper size and recyclable, making it a promising candidate for CCS. While SCH based CCS technology is in the developing stage and great efforts have to be conducted to improve the performance that is determined by their thermodynamical and structural properties. This review summarizes and compares the thermodynamic and structural properties of SCH and quaternary salt hydrates with gas mixtures to be captured and separated. Based on the description of the physical properties of SCH and hydrate of quaternary salts with gas mixture, the CO 2 capture and separation from fuel gas, flue gas and biogas with SCH are reviewed. The review focuses on the use of tetra- n-butyl ammonium halide and tetra- n-butyl phosphonium halide, which are the current application hotspots. This review aims to provide guidance for the future applications of SCH.
