Latest ArticlesThe dysbiosis of oral microbiota contributes to diseases such as periodontitis and certain cancers by triggering the host inflammatory response. Developing methods for the immediate and sensitive identification of oral microorganism is crucial for the rapid diagnosis and early interventions of associated diseases. Traditional methods for microbial detection primarily include the plate culturing, polymerase chain reaction and enzyme-linked immunosorbent assay, which are either time-consuming or laborious. Herein, we reported a persistent luminescence-encoded multiple-channel optical sensing array and achieved the rapid and accurate identification of oral-derived microorganisms. Our results demonstrate that electrostatic attractions and hydrophobic-hydrophobic interactions dominate the binding of the persistent luminescent nanoprobes to oral microorganisms and the microbial identification process can be finished within 30 min. Specifically, a total of 7 oral-derived microorganisms demonstrate their own response patterns and were differentiated by linear discriminant analysis (LDA) with the accuracy up to 100% both in the solution and artificial saliva samples. Moreover, the persistent luminescence encoded array sensor could also discern the microorganism mixtures with the accuracy up to 100%. The proposed persistent luminescence encoding sensor arrays in this work might offer new ideas for rapid and accurate oral-derived microorganism detection, and provide new ways for disease diagnosis associated with microbial metabolism.
The contamination of water resources by phenolic compounds (PCs) presents a significant environmental hazard, necessitating the development of novel materials and methodologies for effective mitigation. In this study, a metallic copper-doped zeolitic imidazolate framework was pyrolyzed and designated as Cu-NC-20 for the activation of peroxymonosulfate (PMS) to degrade phenol (PE). Cu-NC-20 could effectively address the issue of metal agglomeration while simultaneously diminishing copper dissolution during the activation of PMS reactions. The Cu-NC-20 catalyst exhibited a rapid degradation rate for PE across a broad pH range (3–9) and demonstrated high tolerance towards coexisting ions. According to scavenger experiments and electron paramagnetic resonance analysis, singlet oxygen (1O2) and high-valent copper-oxo (Cu(Ⅲ)) were the predominant reactive oxygen species, indicating that the system was nonradical-dominated during the degradation process. The quantitative structure-activity relationship (QSAR) between the oxidation rate constants of various substituted phenols and Hammett constants was established. It indicated that the Cu-NC-20/PMS system had the optimal oxidation rate constant with σ− correlation and exhibited a typical electrophilic reaction pattern. This study provides a comprehensive understanding of the heterogeneous activation process for the selective removal of phenolic compounds.
Membrane electrode assembly (MEA) is widely considered to be the most promising type of electrolyzer for the practical application of electrochemical CO2 reduction reaction (CO2RR). In MEAs, a square-shaped cross-section in the flow channel is normally adopted, the configuration optimization of which could potentially enhance the performance of the electrolyzer. This paper describes the numerical simulation study on the impact of the flow-channel cross-section shapes in the MEA electrolyzer for CO2RR. The results show that wide flow channels with low heights are beneficial to the CO2RR by providing a uniform flow field of CO2, especially at high current densities. Moreover, the larger the electrolyzer, the more significant the effect is. This study provides a theoretical basis for the design of high-performance MEA electrolyzers for CO2RR.
Diradicaloid polycyclic hydrocarbons (PHs) own unique open-shell electronic structures and exhibit potential utility in the fields of organic electronics and spintronics. Herein, we disclose precise fusion of B/O-heterocycles onto PHs for control over their electronic structures and diradical properties. We designed and synthesized four B/O-containing diradicaloid isomers that feature the fluoreno[3,2-b]fluorene and fluoreno[2,1-a]fluorene π-skeletons, respectively. The precise B/O-heterocycle fusion modes along with the changed conjugation patterns lead to their modulated electronic structures and properties, such as diradical and aromatic structures, energy levels and band gaps, as well as magnetic, electrochemical and photophysical properties. Notably, the mode A may decrease the open-shell extent, whereas the mode B can enhance the diradical nature, leading to their well-tuned diradical characters in the range of 0.46‒0.70. Moreover, the mode A stabilizes the LUMOs and the mode B obviously increases the HOMO levels, which are remarkably contributed by the B and O atoms, respectively, further giving rise to the decreased band gaps and redshifted absorptions. This study clearly illustrates the electronic effects of B/O-heterocycle fusion on PHs and gains insight into B/O-type organic diradicaloids. These findings will provide an important guideline for the design of more fascinating heteroatom-containing diradicaloids.
The synthesis of polyurethanes (PUs) from the reaction of low molecular weight poly(ethylene carbonate) diol (PECD) is rarely investigated. This work reports a novel PU with excellent mechanical properties from the solution polymerization of 4,4′-diphenylmethane diisocyanate (MDI) with PECD that was derived from the copolymerization of carbon dioxide (CO2) and ethylene oxide (EO). The tensile strength, the elongation at break and 300% constant tensile strength of the PECD-PU were up to 66 ± 2 MPa, 880% ± 50% and 13 MPa, respectively, higher than the control PUs from the reaction of MDI with commercial polyethers or polyesters. The PECD-PU with high CO2 carbonate content exhibited good solvent resistance and chemical stability. Of importance, the mechanical properties and chemical resistance of PECD-PU were significantly enhanced with the increasing content of CO2, i.e., the carbonate unit in PECD. This work provides comprehensive properties of PECD-derived PUs, indicating that PECD is a competitive precursor for the preparation of PU and has broad application prospects.
Rational design of viable routes to obtain efficient and stable oxygen evolution reaction (OER) electrocatalysts remains challenging, especially under industrial conditions. Here, we provide a solvent-steam assisted corrosion engineering strategy to directly fabricate high-entropy NiFe-LDH with spatially resolved structural order. Ammonium fluoride in methanol steam enables the formation of nanosheets while Fe3+ effectively enhances their adhesion to the semi-sacrificial nickel-iron foam (NFF), thereby conjuring up a NiFe-LDH@NFF catalyst that exhibits remarkable adaptability to robust electrochemical activation yet with excellent stability. Comprehensive measurements reveal the in-situ formation of high-valance metal oxyhydroxide and the enhancement of adsorption-desorption process. Under the industrial condition (6 mol/L KOH, 60 ℃), the NiFe-LDH@NFF exhibits excellent activity of 50 mA/cm2 at 1.55 V and high durability of over 120 h at 200 mA/cm2. We anticipate that the steam assisted strategy could promote the development of efficient non-precious electrocatalysts for hydrogen energy.
Photocatalytic CO2 reduction reaction (CO2RR) is one of the promising strategies for sustainably producing solar fuels. The precise identification of catalytic sites and the enhancement of photocatalytic CO2 conversion is imperative yet quite challenging. This critical review summarizes recent advances in porous photo-responsive polymers, including covalent organic frameworks (COFs), covalent triazine frameworks (CTFs), and conjugated microporous polymers (CMPs), those can be rationally designed from the molecular level for visible-light-driven photocatalytic CO2 reduction. Additionally, special emphasis is placed on how the well-defined active sites on these polymers can influence their properties and photocatalytic performance. The precise regulation and control of microenvironments and electronic properties of metal active centers are crucial for boosting catalytic efficiency and selectivity, as well as for the design of better photocatalysts for CO2 reduction.
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