Microbial synthesis of antimony sulfide to prepare catechol and hydroquinone electrochemical sensor by pyrolysis and carbonization.

The application of antimony sulfide sensors, characterized by their exceptional stability and selectivity, is of emerging interest in detection research, and the integration of graphitized carbon materials is expected to further enhance their electrochemical performance. This study represents a pioneering effort in the synthesis of carbon-doped antimony sulfide materials through the pyrolysis of the mixture of microorganisms and their synthetic antimony sulfide. The prepared materials are subsequently applied to electrochemical sensors for monitoring the highly toxic compounds catechol (CC) and hydroquinone (HQ) in the environment. Via cyclic voltammetry (CV) and impedance testing, we concluded that the pyrolytic product at 700 °C (Sb-700) demonstrated the best electrochemical properties. Differential pulse voltammetry (DPV) revealed impressive separation when utilizing Sb-700/GCE for simultaneous detection of CC and HQ, exhibiting good linearity within the concentration range of 0.1-140 µM. The achieved sensitivities of 24.62 µA µM-1 cm-2 and 22.10 µA µM-1 cm-2 surpassed those of most CC and HQ electrochemical sensors. Meanwhile, the detection limits for CC and HQ were as low as 0.18 µM and 0.16 µM (S/N = 3), respectively. Additional tests confirmed the good selectivity, reproducibility, and long-term stability of Sb-700/GCE, which was effective in detecting CC and HQ in tap water and river water, with recovery rates of 100.7%-104.5% and 96.5%-101.4%, respectively. It provides a method that combines green microbial synthesis and simple pyrolysis for the preparation of electrode materials in CC and HQ electrochemical sensors, and also offers a new perspective for the application of microbial synthesized materials.

Pincer Nickel-Catalyzed Olefination of Alcohols with Benzylphosphine Oxides.

N,N,P-Pincer nickel complexes effectively catalyze reaction of alcohols with benzylphosphine oxides to form alkenes in good yields. The protocol suits for a wide scope of substrates and generates only E-configurated alkenes. The method also shows good compatibility of functional groups. Methoxy, methylthio, trifluoromethyl, ketal, fluoro, chloro, bromo, thienyl, and furyl groups are tolerated. The mechanism studies support that the reaction proceeds through catalytic dehydrogenation of alcohols to aldehydes or ketones followed by condensation with benzyldiphenylphosphine oxides in the presence of KOtBu.

Ruthenium(II)-Catalyzed S(II)-Directed Aromatic C-H Allylation with Vinylaziridines.

The ruthenium-catalyzed reaction of aryl methyl thioethers with vinylaziridines affords ortho-position mono- or bis-allylation products depending on substituents on the phenyl rings of sulfide substrates or the ratio of reactants. The reaction also features mild reaction conditions, good product yields, wide scope of substrates, good compatibility of functional groups, and the selective formation of E-configurated C-C double bonds.

Spark plasma sintering of MgAl2O4:Mn2+ transparent ceramic phosphors with low thermal quenching, narrow-band green emission.

MgAl2O4:Mn2+ transparent ceramics were fabricated by reactive spark plasma sintering (SPS). The ceramic samples show narrow-band green emission under the 450 nm blue light excitation, which is corresponding to 4T1(4 G)-6A1(6S) transition of Mn2+ in the tetrahedral site. The emission peak of the Mg0.93Al2O4:0.07Mn2+ ceramic sample was located at 525 nm with the full-width at half-maximum (FWHM) value of 36 nm. The internal quantum yield (IQY) of Mg0.93Al2O4:0.07Mn2+ reached 63%. The emission intensity remained ∼98% at 150 °C compared to its initial value at room temperature, showing excellent thermal quenching performance. The results indicated that MgAl2O4:Mn2+ ceramic phosphor is a promising candidate for high brightness, wide gamut display backlight applications.

Copper-Catalyzed Reaction of 2,3-Allenols with Silylzinc Reagents: Access to 2-Silyl-1,3-butadienes.

Reaction of 2,3-allenols with PhMe2SiZnCl or Ph2MeSiZnCl under catalysis of IPrCuCl or SIPrCuCl was carried out, affording 2-silyl-1,3-butadienes. Secondary and tertiary 2,3-allenols could be used as coupling partners. Reaction of secondary 2,3-allenols gave (E)-2-silyl-1,3-butadienes as the only products.

Enhanced Photocatalytic Water Decontamination by Micro-Nano Bubbles: Measurements and Mechanisms.

Despite recent advancements in photocatalysis enabled by materials science innovations, the application of photocatalysts in water treatment is still hampered due to low overall efficiency. Herein, we present a TiO2 photocatalytic process with significantly enhanced efficiency by the introduction of micro-nano bubbles (MNBs). Notably, the removal rate of a model organic contaminant (methylene blue, MB) in an air MNB-assisted photocatalytic degradation (PCD) process was 41-141% higher than that obtained in conventional macrobubble (MaB)-assisted PCD under identical conditions. Experimental observations and supporting mechanistic modeling suggest that the enhanced photocatalytic degradation is attributed to the combined effects of increased dissolution of oxygen, improved colloidal stability and dispersion of the TiO2 nanocatalysts, and interfacial photoelectric effects of TiO2/MNB suspensions. The maximum dissolved oxygen (DO) concentration of the MNB suspension (i.e., 11.7 mg/L) was 32% higher than that of an MaB-aerated aqueous solution (i.e., 8.8 mg/L), thus accelerating the hole oxidation of H2O on TiO2. We further confirmed that the MNBs induced unique light-scattering effects, consequently increasing the optical path length in the TiO2/MNB suspension by 7.6%. A force balance model confirmed that a three-phase contact was formed on the surface of the bubble-TiO2 complex, which promoted high complex stability and PCD performance. Overall, this study demonstrates the enhanced photocatalytic water decontamination by MNBs and provides the underlying mechanisms for the process.

Flocculent Cu Caused by the Jahn-Teller Effect Improved the Performance of Mg-MOF-74 as an Anode Material for Lithium-Ion Batteries.

Mg-MOF-74/Cu was synthesized by a one-step method and then using the product as a lithium-ion anode material. The flocculent Cu caused by the Jahn-Teller effect conspicuously improves the electrochemical performance of Mg-MOF-74 by enhancing the conductivity of electrode materials. The as-prepared materials exhibited superior rate performance (298.3 mAh g-1 at a current density of 2000 mA g-1) and remarkable cyclability (a specific capacity of 534.5 mAh g-1 is obtained after 300 cycles at 500 mA g-1, which remains at 89.1%). In addition, an electrochemical test of coating an anode material on a stainless steel sheet has also been carried out, and the performance is comparable to that of traditional coating on copper foil (a reversible capacity of 531.7 mAh g-1 is collected, which retains 88.7% of initial capacity). The superior performance, facile one-step synthesis, and low cost of Mg-MOF-74/Cu show promise for practical applications.

Intensifying ozonation treatment of municipal secondary effluent using a combination of microbubbles and ultraviolet irradiation.

Ozonation treatment of municipal secondary effluent is complicated by the low solubility of ozone and inefficient production of hydroxyl free radicals from ozone decomposition. To resolve these problems, this study investigated methods for intensifying ozonation treatment, using a combination of microbubbles and ultraviolet (UV) irradiation (UV/MBO). The high efficiency of the method was illustrated by treating river water containing refractory components derived from secondary effluent in a wastewater treatment plant. The results showed that the ozone mass transfer coefficient in a microbubble system was an order of magnitude compared with a conventional macrobubble system at the initial stage. The amount of ·OH generated during the treatment was quantified using a fluorescent probe analysis. The amount of ·OH in the UV/MBO system was almost 2-6 times more than the amount found with conventional ozonation using macrobubbles (CO), CO with UV irradiation (UV/CO), and microbubble ozonation (MBO) units. The UV/MBO system achieved chemical oxygen demand (COD), UV254, and UV400 removal performance rates of up to 37.50%, 81.15%, and 94.74% respectively. These levels were 2-36% higher than those in other systems. The coupling UV/MBO treatment significantly reduced all five categories of substances according to EEM spectra and fluorescence regional integration. The distribution of fractions with different molecular weights (MW) was altered and the UV254 of MW (< 500 Da) increased by 15.8%. The biodegradability of the water was significantly improved, as indicated by the TOC/UV254. This is ascribed to the enhanced degradation of refractory organics in the water. The combination of the UV/microbubble technique with ozonation could provide an efficient approach for advanced wastewater treatment. Graphical abstract.