Latest ArticlesGaining an understanding of the growth mechanism from single atoms to clusters and bulk materials continues to present a challenge. Thus, it is important to explore the evolving trends of clusters in the structure and properties during the size evolution. In this work, we report the synthesis and characterization of two medium-sized chain-like polyarsenic anions. [As21]3– represents a trimeric example of polyarsenic anion assembled through oxidative coupling of As73– anions. The anion As184– included in [As18Mo2(CO)8]4– is regarded as formed by two realgar-type As8 subunits connected by a dinuclear As-As dumbbell. The As18 cluster was previously predicted by theory, and this is the first time successfully synthesized using wet chemistry method. Besides, small-sized polyarsenides As22– and As102– were found in compound [K(18-crown-6)]3[As10]0.5[As4{Mo(CO)3}2]0.5·2en. Among these, the former exhibits coordination with metal atoms. Single-crystal X-ray diffraction combined with quantum chemical calculations revealed the formation of double bonded As22– stabilized by metal carbonyl groups. This work demonstrates a novel synthetic approach for the preparation of new polyarsenides and highlights their intriguing bonding characteristics, laying the foundation for the synthesis of such compounds and paving the way for their potential applications.
To surmount the obstacles of traditional Fenton method and synchronously utilize Cu2+ and polyphenol in water, an improved Fenton-like reaction applying calcium peroxide (CaO2) as H2O2 source and regulating by the complex of Cu2+-tartaric acid (TA, a representative of polyphenol) was constructed. A typical antibiotic, metronidazole (MTZ) could be effectively eliminated by the Cu2+/TA/CaO2 system, and the optimized parameters were as follows: 0.1 mmol/L Cu2+, 2 mmol/L TA, 2 mmol/L CaO2, and initial pH 5. UV spectrum confirmed the formation of Cu2+-TA complex, which promoted the Cu2+/Cu+ circulation through decreasing the Cu2+/Cu+ couple redox potential, which further enhanced the H2O2 decomposition and the formation of reactive species. Hydroxyl radical was dominant for MTZ degradation, followed by oxygen and superoxide radical. The degradation intermediates of MTZ were detected and their evolution way was speculated. Furthermore, the ternary process showed a wide pH tolerance (3–8) for removing MTZ and broad applicability for eliminating other dyes and antibiotics. This work provided a reference for Cu-based Fenton-like strategy for organic wastewater settlement.
The efficient and environmentally friendly recycling technology of waste residue that including abundant heavy metal produced during the recovery of lithium batteries has become a research hotspot. Herein, a novelty process of acid leaching-selective electrodeposition-deep impurity removal-regeneration was proposed to recovery of the CuS slag, which has been efficient transferred to high purity cathode copper and commercially available ternary precursors. Copper cathode with a purity of 99.67% was prepared under electrochemical reaction conditions at −0.55 V for 2 h. A novel impurity remover-Mn powder, which was used to remove the residual impurities and as a feedstock for the ternary precursor. Finally, NCM523 was regenerated by co-precipitation. The process is superior to the traditional process in economy, energy consumption, CO2 emissions, product purity and process duration. This study provides a new approach for solid waste recovery and precious metal enrichment.
Zero thermal expansion materials are important for the practical applications due to their shape stability as changing temperature. The reported concept of average atomic volume is an available method to hunt new zero thermal expansion materials. Here, according to this concept, a tetragonal tungstate Cs2W3O10 with zero expansion has been found. There is no structure phase transition as increasing temperature from 150 K to 573 K. The coefficient of thermal expansion of axes and volume are αa = 0.0074 × 10−6 K−1, αc = 1.63 × 10−6 K−1, and αV = 1.60 × 10−6 K−1, respectively, in the temperature range of 150 ~ 573 K. The temperature- and pressure-dependent Raman spectra reveal that the vibrations of WO6 octahedra libration modes with positive total anharmonicity and W-O-W bending mode with negative Grüneisen parameter are possibly the origin of zero thermal expansion in Cs2W3O10.
Chemical sensor arrays can obtain more comprehensive analyte information through high-dimensional data. It is of great significance in the analysis of multi-component complex samples. This review summarizes the development and status of chemical sensor arrays. We focused on the design of chemical sensor arrays based on various sensing materials. In addition, several pattern recognition methods in chemometrics are introduced. And applications of chemical sensor arrays in food monitoring, medical diagnosis, and environmental monitoring are illustrated. Based on the analysis of the limitations of current sensor array technology, the direction of the array is also predicted. This review aims to help the broad readership understand the research state of chemical sensor arrays and their development prospects.
Insufficient intratumoral retention of nanomedicines remains the major challenge for broad implementation in clinical sets. Herein, we proposed a legumain-triggered aggregable gold nanoparticle (GNP) delivery platform (GNPs-A&C). GNPs-A&C could form intratumoral or intracellular aggregates in response to the overexpressed legumain. The aggregates with size increase not only could reduce back-flow from interstitial space to peripheral bloodstream but also could restrict the cellular exocytosis, leading to enhanced intratumoral retention. In vitro studies demonstrated that GNPs-A&C possessed an excellent legumain responsiveness and the increased size was closely relevant with legumain expression. In vivo studies demonstrated GNPs-A&C possessed slower clearance rate and much higher intratumoral retention within legumain-overexpressed tumor compared to non-aggregable NPs, regardless of intravenous or intratumoral injection. More importantly, this delivery platform significantly improved the chemotherapeutic effect of doxorubicin (DOX) towards subcutaneous xenograft C6 tumor. The effectiveness of this stimulus-responsive aggregable delivery system provides a thinking for designing more intelligent size-tunable nanomedicine that can substantially improve intratumoral retention.
Electrochemical CO reduction (ECOR) as a potential strategy for producing valuable chemicals and fuels has captured substantial attention. However, the currently available electrocatalysts suffer from poor selectivity and low Faradaic efficiency, limiting their industrial application. Herein, we systematically investigate the potential of homonuclear bimetallic electrocatalysts, TM2@C9N4 (TM = Fe, Co, Ni, and Cu), for the ECOR through extensive density functional theory calculations. Our findings suggest that all four proposed monolayers exhibit exceptional stability, making them highly suitable for experimental synthesis and practical applications. Interestingly, these transition-metal dual atoms anchored on C9N4 monolayers show great potential in facilitating the production of high-value C2 products, such as C2H5OH and C2H4, due to the significantly low limiting potentials (-0.06~-0.46 V) and small kinetic energy barriers (0.54–1.08 eV) for the CO coupling process. Moreover, with the exception of Ni2@C9N4, these bimetallic catalysts demonstrate the impressive suppression of the competitive hydrogen evolution reaction (HER), leading to a high selectivity for C2 products in ECOR. Our predictions would accelerate the development of high-performance C9N4-based dual-atom catalysts for the ECOR.
Aqueous perfluorooctanoic acid (PFOA) elimination has raised significant concerns due to its persistence and bioaccumulation. Although β-PbO2 plate anodes have shown efficient mineralization of PFOA, it remains unclear whether PFOA can be effectively degraded using β-PbO2 reactive electrochemical membrane (REM). Herein, we assessed the performance of Ti/SnO2-Sb/La-PbO2 REM for PFOA removal and proposed a possible degradation mechanism. At a current density of 10 mA/cm2 and a membrane flux of 8500 (liters per square meter per hour, LMH), the degradation efficiency of 10 mg/L PFOA was merely 8.8%, whereas the degradation efficiency of 0.1 mg/L PFOA increased to 96.6%. Although the porous structure of the β-PbO2 REM provided numerous electroactive sites for PFOA, the generated oxygen bubbles in the pores could block the pore channels and adsorb PFOA molecules. These hindered the protonation process and significantly impeded the degradation of high-concentration PFOA. Quenching experiments indicated that •OH played dominant role in PFOA degradation. The electrical energy per order to remove 0.1 mg/L PFOA was merely 0.74 Wh/L, which was almost an order of magnitude lower than that of other anode materials. This study presents fresh opportunities for the electrochemical degradation of low-concentration PFOA using β-PbO2 REM.
Developing efficient and long wavelength sensitive unimolecular photoinitiators (PIs) is still facing a great challenge. In this work, a series of thioxanthone-based N-hydroxyphthalimide esters (TX-NHPIEs) were synthesized by installing NHPIEs along the TX backbone and characterized. The investigated TX-NHPIEs have a 60 nm redshift and demonstrate sterling initiating efficiency for free radical photopolymerization (FRP) under LED@450 nm light irradiation compared with the commercialized isopropylthioxanthone (ITX). Real-time 1Hnuclear magnetic resonance (1H NMR), electron spin resonance (ESR), decarboxylation and gas chromatograph-mass spectrometer (GC–MS) experiments and density functional theory (DFT) reveal that TX-NHPIEs can generate one alkyl radical and one N-centered iminyl radical, which can initiate FRP directly and indirectly, respectively. In other words, TX-NHPIEs absorb one photon and can generate two active radicals, which break through the limitations of common PIs. TX-NHPIE-Cpe demonstrates the highest initiating efficiency, and its application in coatings and 3D printing was also studied, indicating TX-NHPIEs have broad potential applications in photopolymerization processes.
COVID-19 is a major event with worldwide influences. Since the beginning of the epidemic, pharmaceutical chemists have paid attention to the therapeutic effect of a variety of small molecule medicines on COVID-19 infection. A series of organic molecules are designed and found to be effective in the treatment of COVID-19 infection. In fact, no matter how effective they are, with the development of the COVID-19 epidemic, various small molecule medicines are gradually recognized by people. This is equivalent to a good science popularization of pharmaceutical chemistry. This review aims to introduce the molecules for COVID-19 treatment on the basis of their chemical structures, synthetic methods as well as their effects.
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