Latest ArticlesBorylative cyclization of E-3-arylallyl carbamoyl chlorides is achieved through copper catalyzed intramolecular carboboration with B2pin2. 2-Aryl-3-boryl-γ-lactams are formed with exclusive cis-diastereoselectivity. CuBr-Dppp combination gives the best outcomes. The substrate scope is profiled.
With regard to the reaction of higher alcohol synthesis (HAS), the optimizations of activity and selectivity towards C2+ alcohol are restricted by the improper equilibrium in two different CO activation pathways and chain growth capacity. Herein, we find that delibrately controlling the compositions of catalysts is an effective strategy to achieve the equilibrium of CO activation pathways and promote the chain growth. As a result, the optimized Cu0.25Co0.75 alloy catalyst can achieve a large proportion of higher alcohol in alcohol products (C2+OH/MeOH = 4.40), together with high CO conversion of 71.27% and space-time-yield of 147.65 g kg−1 h−1. The mechanistic studies suggest that the good performance of Cu0.25Co0.75 catalyst is attributed to the synergistic effect between alloyed Cu and Co.
2D halide perovskites have emerged as promising materials because of their stability and passivation effect in perovskite solar cells (PSCs). However, the introduction of bulky organic ammonium cations from 2D halide perovskites would decrease the device performance generally compared to the traditional 3D MAPbI3. Incorporation of ultrathin 2D halide perovskite nanosheets (NSs) with 3D MAPbI3 could address this issue. Herein, we report a rationally designed PSCs with dimensional graded 3D/2D MAPbI3/(PEA)2PbI4 heterojunction, in which 2D (PEA)2PbI4 NSs were synthesized and incorporated between 3D MAPbI3 and hole-transporting layer. Besides the significantly improved stability, a notable increasement in power conversion efficiency (PCE) of 20% was obtained for the 3D/2D perovskite solar cells due to the favourable band alignment among (PEA)2PbI4 NSs and the other components. The graded structure of MAPbI3/(PEA)2PbI4 would upshift the energy level continuously, which enhances the hole extraction efficiency thus reduces the interface charge recombination, leading to the increasements of VOC from 1.04 V to 1.07 V, JSC from 21.81 mA/cm2 to 23.15 mA/cm2 and the fill factor from 67.89% to 74.78%, and therefore an overall PCE of 18.53%.
Carbon nanotube film (CNTF) can be used for photocatalysis and water treatment due to its porous structure, good stability and excellent electrical properties. In this work, TiO2/amorphous carbon/carbon nanotube film (TCC) composite with uniform structure was prepared by a simple atomization spraying method. Rhodamine B (RhB) was used to test the photocatalytic activity of TCC. TCC composite exhibits good photocatalytic activity under ultraviolet light. In particular, the degradation efficiency of rhodamine B (RhB) by TCC sprayed with 9 layers of TiO2 (9TCC) increased by 1.45 times than of TiO2 under ultraviolet light. The enhanced photocatalytic activity of TCC is attributed to the CNTF, which can broaden the light response range of TCC and improve the migration efficiency of electrons. The existence of amorphous carbon will promote these advances. Moreover, the better hydrophilic properties would enhance the catalytic performance happened on the solid-liquid interface. Finally, the photocatalytic mechanism and degradation intermediates of the TCC composite were proposed.
In this paper, the process of ammonia borane (AB) hydrolysis generate H2 on the transition metal Fe@Co core-shell structure has been obtained. According to the different roles played by H2O molecules and the number of H2O molecules involved, there are three schemes of reaction paths. Route Ⅰ does not involve the dissociation of H2O molecules and all H atoms come from AB. Moreover, the H2O molecule has no effect on the breaking of the BH bond or the NH bond. The reaction absorbs more heat during the formation of the second and third H2 molecules. Route Ⅱ includes the dissociation of H2O molecules and the cleavage of BH or NH bonds, respectively, and the reaction shows a slight exotherm. Route Ⅲ started from the break of the BN bond and obtained 3H2 molecules through the participation of different numbers of H2O molecules. After multiple comparative analyses, the optimal hydrolysis reaction path has been obtained, and the reaction process can proceed spontaneously at room temperature.
A novel route for tandem C–C/C–N formation, annulation and aromatization of hydrazones with 1, 2-dichloroethane to synthesize 1H-pyrazoles has been developed. Furthermore, the 1, 2-dichloroethane serves as alkylation reagent in good to excellent yields. This methodology features mild reaction conditions and good functional group tolerance, providing a direct approach for the preparation of 1H-pyrazoles.
Nucleic acids with G4 elements play a role in the formation of aggregates involved in intracellular phase transitions. Our previous studies suggest that different forms of DNA could act as an accelerating template in Cu/Zn superoxide dismutase (SOD1) aggregation. Here, we examined the regulation of formation and cytotoxicity of the SOD1 aggregates by single-stranded 12-mer deoxynucleotide oligomers (dN)12 (N = A, T, G, C; ssDNAs) under acidic conditions. The ssDNAs can be divided into two groups based on their roles in SOD1 binding, exposure of hydrophobic clusters in SOD1, accelerated formation, morphology and cytotoxicity of SOD1 aggregates. G-quadruplexes convert SOD1 into fibrillar aggregates as a template, a fact which was observed for the first time in the nucleic acid regulation of protein aggregation. Moreover, the fibrillar or fibril-like SOD1 species with a G-quadruplex provided by (dG)12 were less toxic than the amorphous species with (dN)12 (N = A, T). This study not only indicates that both morphology and cytotoxicity of protein aggregates can be regulated by the protein-bound DNAs, but also help us understand roles of nucleic aid G-quadruplexes in the formation of aggregates and membraneless organelles involved in intracellular phase transitions.
Molybdenum disulfide (MoS2) has excellent trapping ability for lead ions whereas its micro-/nanoscale size has greatly impeded its practical applications in the flow-through systems. Herein, a millimeter-sized nanocomposite MoS2−001 was synthesized for Pb2+ removal by loading MoS2 nanosheets into a polystyrene cation exchanger D-001 by a facile hydrothermal method. The proposed structure and adsorption mechanism of MoS2−001 was confirmed by the scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) analysis. The nanocomposite showed outstanding adsorption capacity and rapid adsorption kinetic for Pb2+ removal, and the adsorption behavior followed the Langmuir adsorption model and pseudo-first-model kinetic model. Pb2+ uptake by MoS2−001 still maintains a high level even in the presence of extremely highly competitive ions (Ca(Ⅱ) and Mg(Ⅱ)), suggesting its high selectivity for Pb2+ adsorption. Besides, the fixed-bed column experiments further certified that MoS2−001 is of great potential for Pb2+ removal from the wastewater in practical engineering applications. Even more gratifying is that the exhausted MoS2−001 can be regenerated by NaCl-EDTANa2 solution without any significant adsorption capacity loss. Consequently, all the results indicated that MoS2−001 is a promising candidate adsorbent for lead-containing wastewater treatment.
A highly-active, metal-free, carbon-based oxygen reduction reaction (ORR) cathode, i.e., graphitized N-doped carbon felt (GNCF), was prepared, for the first time, by in-situ modifying the doping species of polyacrylonitrile (PAN)-based carbon felt (CF) via a facile annealing process in Ar atmosphere. It was applied for dramatically enhanced organics degradation and electricity generation in a photocatalytic fuel cell (PFC) system. The GNCF showed enhanced specific surface area, improved graphitization and raised ratio of graphitic N, therefore resulting in excellently improved ORR performance compared to the CF. When applying the GNCF as a cathode in a PFC system, the proposed PFC showed significant improvement in degrading various model organic conta minants and outputing electricity simultaneously when compared with the PFC with CF. For instance, the apparent rate constant and electricity output efficiency showed ~10.6 times and ~7.2 times, respectively, improvement when using rhoda mine B as model waste. Further improved performance was also achieved by aeration of air or O2 due to the further enhanced ORR. The proposed PFC was also efficient in a wide pH, and kept outstanding stability in long-term utilization.
A novel GO modified g-C3N4 nanosheets/flower-like BiOBr hybrid photocatalyst is fabricated by a facile method. The characterization results reveal that wrinkled GO is deposited between g-C3N4 nanosheets and flower-like BiOBr forming a Z-scheme heterojunction. As a mediator, plicate GO plays a positive role in prompting photogenerated electrons transferring through its sizeable 2D/2D contact surface area. The g-C3N4/GO/BiOBr hybrid displays a superior photocatalytic ability to g-C3N4 and BiOBr in photodegrading tetracycline (TC), whose removal efficiency could reach 96% within 2 h. Besides, g-C3N4/GO/BiOBr composite can reduce Cr(Ⅵ), and simultaneously treat TC and Cr(Ⅵ) combination contaminant under the visible light. The g-C3N4/GO/BiOBr ternary composite also exhibits satisfactory stability and reusability after four cycling experiments. Further, a feasible mechanism related to the photocatalytic process of g-C3N4/GO/BiOBr is put forward. This study offers a ternary hybrid photocatalyst with eco-friendliness and hopeful application in water pollution.
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