Improved sunlight-driven photocatalytic abatement of tetracycline and photoelectrocatalytic water oxidation by tin oxide quantum dots anchored on nickel ferrite nanoplates

Comprehensive analysis of NiFe2O4/MWCNTs nanocomposite to degrade a healthcare waste - tetracycline

Tetracycline (TC), a commonly used antibiotic for studying bacterial illnesses in living organisms, poses a significant risk to the aquatic environment. Despite various conventional methods having been attempted to remove TC antibiotics from water solutions, they have not proven effective. Consequently, the focus of the research is on the photocatalytic degradation of TC. According to the research, MWCNTs were successfully incorporated into NiFe2O4 nanoparticles, which reduced the pace at which charge carriers recombined after joining with MWCNTs. Subsequently, the catalyst's efficacy was assessed in a batch reactor by analyzing the weight percentage change of the nanocomposite, the initial concentration of TC antibiotics, the effects of pH and contact time. The identical operational parameters were employed to investigate the degradation of TC using NiFe2O4 and MWCNTs as individual pure materials. The findings indicated that the photocatalytic process using NiFe2O4/MWCNTs achieved a degradation efficiency of 95.8% for TC at a pH value of 9. This result was obtained after a reaction time of 120 minutes, the concentration of TC solution was 10 mg L-1, with a nanocomposite dose of 0.6 g L-1 of TN 04 and 120 W m-2. The pseudo-first-order approach was used to estimate the rate at which TC degrades. After four consecutive uses, it was observed that the photocatalysts maintained their original properties, with only a slight decrease of approximately 2.4% in the removal efficiency. The study demonstrated that the NiFe2O4/MWCNTs nanocomposite exhibited considerable efficiency in degrading TC. Due to its simple manufacture and useful recovery, it has the potential to function well as a catalyst for the removal and degradation of pharmaceutical organic contaminants.

Two-Dimensional Sb Modified TiO2 Nanorod Arrays as Photoanodes for Efficient Solar Water Splitting

As one of the widely studied semiconductor materials, titanium dioxide (TiO₂) exhibits high photoelectrochemical (PEC) water-splitting performance as well as high chemical and photo stability. However, limited by a wide band gap and fast electron-hole recombination rate, the low solar-to-hydrogen conversion efficiency remains a bottleneck for the practical application of TiO₂-based photoelectrodes. To improve the charge separation and water oxidation efficiency of TiO₂ photoanodes, antimonene, a two-dimensional (2D) material obtained by liquid-phase exfoliation, was assembled onto TiO₂ nanorod arrays (TNRAs) by a simple drop-coating assembly process. PEC measurements showed that the resulting 2D Sb/TiO₂ photoelectrode displayed an enhanced photocurrent density of about 1.32 mA cm^-2 in 1.0 M KOH at 0.3 V vs. Hg/HgO, which is ~1.65 times higher than that of the pristine TNRAs. Through UV-Vis absorption and electrochemical impedance spectroscopy measurements, it was possible to ascribe the enhanced PEC performances of the 2D Sb/TiO₂ photoanode to increased absorption intensity in the visible light region, and improved interfacial charge-transfer kinetics in the 2D Sb/TiO₂ heterojunction, which promotes electron-hole separation, transfer, and collection.

Palladium-Supported Polydopamine-Coated NiFe2O4@TiO2: A Sole Photocatalyst for Suzuki and Sonogashira Coupling Reactions under Sunlight Irradiation

The effective utilization of solar energy in synthetic organic chemistry has gained extensive attention owing to its enormous energy and environmentally benign nature. In this context, we designed and synthesized a magnetically retrievable, sole palladium (Pd)-supported polydopamine-coated core@shell (NiFe₂O₄@TiO₂) heterogeneous nanophotocatalyst for Suzuki and Sonogashira coupling reactions under sunlight irradiation. The synthesized catalyst was characterized by powder X-ray diffraction (PXRD), Fourier-transform infrared, UV-vis, scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and vibrating sample magnetometer analysis. The photocatalytic activity of the synthesized nanocatalyst under sunlight irradiation was assessed for both Suzuki and Sonogashira coupling reactions, where it worked excellently well with a high yield of the product up to 98 and 96%, respectively. Its efficacy was also investigated in the conversion of substituted substrates in both the coupling reactions into desired biaryls and diarylacetylenes. Unique features of the synthesized catalyst are (i) its effective performance for both the aforesaid coupling reactions under ambient reaction conditions for a short reaction time in polar protic solvents (ethanolic water/EtOH) with good yield without any byproduct, (ii) magnetic retrieval of the catalyst from the reaction mixture employing an external magnet is an added advantage, and (iii) the retrieved catalyst could potentially be reutilized for up to five consecutive runs without appreciable diminution of catalytic efficacy, and its stability was confirmed by inductively coupled plasma optical emission spectroscopy analysis and XRD.

Visible-light-driven indium vanadium oxide nanosheets supported bismuth tungsten oxide nanoflakes heterostructure as an efficient photocatalyst for the tetracycline degradation

The development of excellent photocatalysts is of great significance for the efficient photocatalytic degradation process, however, the low carrier separation efficiency and poor light absorption ability typically limit the performance of photocatalysts. Herein, a visible light responsive heterostructure composed with indium vanadium oxide nanosheets supported bismuth tungsten oxide nanoflakes (InVO₄/Bi₂WO₆) was synthetized through in-situ hydrothermal method. Further, the photocatalytic activity was performed for tetracycline (TC) under visible light illumination. The InVO₄/Bi₂WO₆ heterostructure builds a strong interface between InVO₄ and Bi₂WO₆ to hinder reunion of photoinduced charge carriers, and provides the sensitive agents for the removal of TC. In particular, the InVO₄/Bi₂WO₆ photocatalyst prepared by taking 5.0 mg of Bi₂WO₆ shows the highest degradation of TC about 97.42% in 72 min. The quenching experiments identified that hydroxyl radicals, and holes dominated in the photocatalytic process. Furthermore, the optimized nanocomposite is stable even after four cycles, which exposes the excellent photostability and reusability of the photocatalyst. In addition, a plausible degradation pathway and mechanism of TC over InVO₄/Bi₂WO₆ nanocomposite is also projected.