Ternary heterogeneous Z-scheme photocatalyst TiO2/CuInS2/OCN incorporated with carbon quantum dots (CQDs) for enhanced photocatalytic degradation efficiency of reactive yellow 145 dye in water

Photocatalysis oxidative desulfurization of dibenzothiophene in extremely deep liquid fuels on the Z-scheme catalyst ZnO-CuInS2-ZnS intelligently integrated with carbon quantum dots: performance, mechanism, and stability

In this study, we improved the electrochemical and photocatalytic properties of the ZnO-CuInS2-ZnS (ZCZ) material by integrating with carbon quantum dots (CQD) with particle sizes from 2 to 5 nm. The integration of ZnO-CuInS2-ZnS with carbon quantum dots (ZnO-CuInS2-ZnS/CQD:ZCZ-CQD) enhanced the visible light absorption, significantly reduced the electron-hole recombination rate, and facilitated the electron transfer and separation processes as confirmed by UV-visible diffuse reflectance spectroscopy (UV-vis DRS), photoluminescence (PL), and electrochemical impedance spectroscopy (EIS). The successful integration of ZCZ with carbon quantum dots was confirmed using X-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS) and transmission electron microscopy (TEM) methods. The ZCZ/CQD photocatalyst removed up to 98.32% of DBT after 120 minutes of reaction, maintained over 90% durability after 10 cycles, and retained its structure without any changes. The ZCZ photocatalyst integrated with CQD enhances faster dibenzothiophene (DBT) removal by 4.46, 3.24, 2.53, and 1.72 times compared to ZnO, CuInS2, ZnS, and ZnO-CuInS2-ZnS, respectively. Factors influencing the oxidation process of DBT including the mass of the photocatalyst, initial DBT concentration, stability, and reaction kinetics were studied. Through active species trapping experiments, this study demonstrated that the formation of ˙O2 - and ˙OH radicals determines the reaction rate. The mechanism of photocatalysis on ZCZ-CQD materials and the intermediate products formed in the process of photocatalytic oxidative desulfurization of dibenzothiophene is proposed based on electrochemical measurements and GC-MS results.

Fabrication and characterization of a chitosan/cyclodextrin/TiO2-NPs composite for preservation of avocados

In this study, a TiO2 material with nanoparticle size of about 10-20 nm, surface area of 109 m2 g-1 was synthesized using the microwave-assisted hydrothermal method. The chitosan/TiO2 film combined with cyclodextrin (chitosan-cyclodextrin/TiO2, CS-CD/TiO2NPs) helps significantly improve the mechanical properties and enhance the antibacterial activity of the polymer film. Furthermore, the content of TiO2 nanoparticles in CS-CD/TiO2NPs also affects the tensile strength, antibacterial activity, ripening rate, ethylene production rate, and water vapor permeability during food preservation of the CS-CD film that has been studied. The CS-CD/TiO2NPs film is effective against Gram-negative bacteria (Escherichia coli) and Gram-positive bacteria (Staphylococcus aereus) reaching over 99.5% after 15 min of contact. The preservation ability of avocados coated with CS-CD/TiO2NPs was evaluated through some physiological parameters of the avocados, such as sensory evaluation, weight loss, and hardness. The results show that the use of CS-CD/TiO2NPs films extends the preservation time of avocados up to 7 days under conditions of 30 °C and 80% relative humidity.

Enhanced Degradation of Levofloxacin through Visible-Light-Driven Peroxymonosulfate Activation over CuInS2/g-C3N4 Heterojunctions

In this work, the heterojunctions of CuInS2 embedded in the g-C3N4 materials (xCuInS2/g-C3N4, abbreviated as xCIS/GCN) was successfully prepared for peroxymonosulfate (PMS) activation under visible light. The catalysts are characterized by different techniques, such as XRD, FTIR, SEM, TEM, and UV-vis. The unique heterojunction composites can suppress the recombination of photogenerated pairs. The catalytic results showed that the 3CIS/GCN exhibited excellent catalytic levofloxacin (LVF) degradation efficiency, while more than 98.9% of LVF was removed in 60 min over a wide pH range. SO4•-, O2•-, OH•, and 1O2 were verified as the main reactive species for LVF degradation via the quenching experiments and electron paramagnetic resonance technology (EPR). The synergetic effect of xCIS/GCN, PMS, and visible light irradiation was discussed. The possible LVF degradation pathway was proposed through byproducts analysis (LC-MS). Moreover, the 3CIS/GCN/vis-PMS system has very low metal leaching. Owing to xCIS/GCN having good properties for PMS activation, it has potential applications for LVF or other hazardous pollutants degradation.