Latest ArticlesHydrogen evolution reaction (HER) and oxygen reduction reaction (ORR) have been considered as two critical processes in the field of electrocatalytic water-splitting for hydrogen production and fuel cells. However, the sluggish reaction kinetics of HER and ORR required efficient electrocatalyst such as Pt to promote such process. Transition metal phosphides (TMPs) exhibit great potential to replace noble metal electrocatalysts to accelerate HER and ORR due to their high activity and easy availability. Herein, a highly-efficient bifunctional CoP electrocatalyst for HER and ORR, featuring a unique core-shell structure decorated on nitrogen-doped carbon matrix was designed and constructed via etching a cobalt-based zeolitic imidazolate framework (ZIF-67) with phytic acid (PA) followed by pyrolysis treatment (PA-ZIF-67–900). Experimental results revealed that the pure-phase single-crystalline CoP exhibited outstanding electrocatalytic performance in HER and ORR, superior to Co(PO3)2 in PA-ZIF-67–700, hybrid phase of Co(PO3)2 and CoP in PA-ZIF-67–800 and Co2P-doped CoP in PA-ZIF-67–1000. To reach the current density of 10 mA/cm2 the as-synthesized CoP required an overpotential of 120 mV for HER in 1 mol/L KOH and half-wave potential of 0.85 V in O2-saturated 0.1 mol/L KOH. This work present new clue for construction of efficient and bifunctional electrocatalyst in the field of energy conversion and storage
Nuclear RNA export into the cytoplasm is one of the key steps in protein expression to realize biological functions. Despite the broad availability of nucleic acid dyes, tracking and quantifying the highly dynamic process of RNA export in live cells is challenging. When dye-labeled RNA enters the cytoplasm, the dye molecules are released upon degradation of the RNA, allowing them to re-enter the cell nucleus. As a result, the ratio between the dye exported with RNA into the cytoplasm and the portion staying inside the nucleus cannot be determined. To address this common limitation, we report the design of a smart probe that can only check into the nucleus once. When adding to cells, this probe rapidly binds with nuclear RNAs in live cells and reacts with intrinsic H2S. This reaction not only activates the fluorescence for RNA tracking but also changes the structure of probe and consequently its intracellular localization. After disassociating from exported RNAs in cytoplasm, the probe preferentially enters lysosomes rather than cell nucleus, enabling real-time quantitative measurement of nuclear RNA exports. Using this probe, we successfully evaluated the effects of hormones and cancer drugs on nuclear RNA export in live cells. Interestingly, we found that hormones inhibiting RNA exports can partially offset the effect of chemotherapy.
Peroxymonosulfate (PMS) activation in heterogeneous processes is a promising water treatment technology. Nevertheless, the high energy consumption and low efficiency during the reaction are ineluctable, due to electron cycling rate limitation. Herein, a new strategy is proposed based on a quantum dots (QDs)/PMS system. Co-ZnS QDs are synthesized by a water phase coprecipitation method. The inequivalent lattice-doping of Co for Zn leads to the generation of surface sulfur vacancies (SVs), which modulates the surface of the catalyst to form an electronic nonequilibrium surface. Astonishingly, the plasticizer micropollutants can be completely degraded within only tens of seconds in the Co-ZnS QDs/PMS system due to this type of surface modulation. The interfacial reaction mechanism is revealed that pollutants tend to be adsorbed on the cobalt metal sites as the electron donors, where the internal electrons of pollutants are captured by the metal species and transferred to the surface SVs. Meanwhile, PMS adsorbed on the SVs is reduced to radicals by capturing electrons, achieving effective electron recovery. Dissolved oxygen (DO) molecules are also easily attracted to catalyst defects and are reduced to O2•−, further promoting the degradation of pollutants.
Radical-mediated reactions have many advantages in the construction of complex molecular scaffolds by forging chemical bonds of high challenge. Diazenes, including 1, 1-diazenes and 1, 2-diazenes, can generate biradical species via nitrogen extrusion under thermal or photochemical conditions. The superior reactivity of the generated biradical enables various types of synthetic transformations with excellent chemoselectivity and has been applied to the complex natural products synthesis. In this mini-review, the modes of reaction are summarized and discussed, namely ring contraction via nitrogen deletion, homo or heterodimerization, trimethylenemethane (TMM)-diyl cycloaddition. Applications of these classes of reactions in complex natural product synthesis are illustrated. Last but not least, the current state, future directions, and opportunities for dinitrogen extrusion reaction from diazenes are highlighted and discussed.
The construction of rich phase interfaces to increase active reaction area in hybrid materials is an excellent strategy to improve electrochemical performance. Under this guideline, MIL-101@OX-metal organic framework (MOF) is constructed by the "MOF on MOF" method, then converts to MIL-101@NiFe-layered double hydroxides (LDH) by in situ transformation in alkaline solution. MIL-101@NiFe-LDH shows excellent electrochemical water oxidation performance. It needs only an overpotential of 215 mV to drive 10 mA/cm2 of oxygen evolution reaction (OER), which is less than that of NiFe-LDH, MIL-101. In addition, MIL-101@NiFe-LDH has the smallest Tafel slope (55.1 mV/dec) compared with NiFe-LDH (61.1 mV/dec), MIL-101 (150.8 mV/dec). The excellent water oxidation activity is due to the high phase interfaces derived from high specific surface area of MOF. This work offers an alternative method for making MOF/LDH heterostructures with an optimized phase interfaces and provides new insights for OER.
Two novel uranium-containing selenotungstates Na3[H19(UO2)2(μ2-O)(Se2W14O52)2]·41H2O (U2) and (NH4)10[H4(SeO)2(UO2)2(H2O)2(H2Se2W14O52)(Se2W14O52)]·66H2O (Se2U2) based on the {Se2W14O52} unit were successfully prepared and fully characterized. To our knowledge, the uranium is firstly introduced into the selenotungstates. Moreover, it is notable that U2 exhibits excellent Lewis acid-base catalytic activities in the condensation cyclization of sulfonyl hydrazides with diketones to synthesize polysubstituted pyrazoles. All the desired products were obtained in moderate to good yields (up to 99%).
Designing visible light photocatalysts with a metal oxide semiconductor as the starting material could expand a new horizon for the conversion and storage of solar energy. Here, the benchmark photocatalyst TiO2 was used to pursue this goal by anchoring aromatic acids. Extending the aromatic acid was strategically deployed to design TiO2 complexes with violet light-induced selective aerobic oxidation of sulfide as the probe reaction. With benzoic acid (BA) as the initial molecule, horizontally extending one or two benzene rings furnishes 2-naphthoic acid (2-NA) and 2-anthracene acid (2-AA). Moreover, triethylamine (TEA), an electron transfer mediator, was introduced to maintain the integrity of the anchored aromatic acids. Notably, there was a direct correlation between the π-conjugation of aromatic acid ligand and the selective aerobic oxidation of sulfides. Among the three aromatic acids, 2-AA delivered the best result over TiO2 due to the most extensive π-conjugated system. Ultimately, violet light-induced selective aerobic oxidation of sulfides into corresponding sulfoxides was conveniently realized by cooperative photocatalysis of 2-AA-TiO2 with 10 mol% of TEA. This work affords an extending strategy for designing the next-generation ligands for semiconductors to expand visible light-induced selective reactions.
A kind of CdS/Cd-BiOCl immobilized films photocatalyst was prepared. The optical and physicochemical properties of the CdS/Cd-BiOCl photocatalysts were analysed, and the detailed characterization revealed CdS/Cd-BiOCl films photocatalyst with good charge carrier separation effect. The reusabilities and photocatalytic properties of the samples were studied. The 15%CdS/Cd-BiOCl photocatalyst exhibited superior performance in photocatalytic degradation of tetracycline (TC) and favorable stability under visible light irradiation. As for the photodegradation rate of TC, 15%CdS/Cd-BiOCl exhibited an excellent photodegradation activity, which is 4.06 and 9.53 times higher than that of CdS/Cd and BiOCl, respectively. The results showed that dominant active species are •O2− and •OH radicals during photodegradation. The charge transfer in Z-scheme CdS/Cd-BiOCl films photocatalyst could synchronously generate conduct band (CB) electrons in BiOCl and valence band (VB) holes in CdS, and metal Cd served as electron mediator. This work can be a reference for the design of film photocatalysts and new insight for photodegradating towards contaminants.
Genomic deoxyribonucleic acid (DNA) is selected as the ideal carrier for preserving and transmitting the genetic information over the course of evolution. However, the genomic DNA is constantly exposed to various endogenous and environmental threats, causing a diversity of damaged bases, lesions, mismatches and base-pair modifications in the genome, eventually leading to genomic instability and cancers. Base excision repair (BER) is the most important repair mechanism, repairing a variety of DNA damages arising from oxidation, alkylation, methylation, deamination, and hydrolysis reactions. DNA glycosylases are responsible for initiating the first step of the BER pathway through cleaving the N-glycosidic bond between the damaged base and the DNA backbone. However, abnormal DNA glycosylases are associated with a variety of diseases such as cancer, cardiovascular disease, neurological disease and inflammation, suggesting the important role of DNA glycosylases in cancer diagnosis and treatment. Therefore, it is highly desirable to monitor the activity of DNA glycosylases, gaining a deep understanding of the restoration process of damaged DNA and clinical diagnosis. Recently, a series of novel DNA glycosylases detection methods with excellent performance have been developed. In this minireview, we summarize the recent advances in DNA glycosylase assays including amplification-free assay and amplification-assisted assay. Firstly, a brief introduction of amplification-free assay for DNA glycosylase is given. Then, amplification-assisted assays for DNA glycosylases are discussed in detail. Ultimately, the conclusion and prospects of the directions of DNA glycosylase assays are provided.
Here, silica microspheres were decorated with two-dimensional metal–organic frameworks (2D MOFs) nanosheets and ionic liquids, and evaluated as the mixed-mode stationary phase for chromatographic separation. The ionic liquids were used to assist the synthesis of 2D MOFs nanosheets, and also acted as adhesives among the nanosheets and silica. In contrast with the 2D MOFs-based column without ionic liquids and commercial columns, the prepared column exhibited enhanced chromatographic separation performance for partially hydrophilic compounds such as alkaloids, sulfonamides and antibiotics, etc. In addition to excellent chromatographic repeatability and stability, it has also been verified that the composites could be easily and repeatedly prepared. The relative standard deviation of the retention time of the same type of analyte between the three batches of materials was ranging from 0.21% to 1.7%. In short, these results indicated that the synthesized composites were promising separation material for liquid chromatography, which made it possible to broaden the application of 2D MOFs in the field of chromatography.