Simultaneous improvement of photocatalytic and superhydrophilicity properties of nano TiO2 thin films

ZrO2/ZnO/TiO2 Nanocomposite Coatings on Stainless Steel for Improved Corrosion Resistance, Biocompatibility, and Antimicrobial Activity

The ultrathin nanocomposite coatings made of zirconium oxide (ZrO₂), zinc oxide (ZnO), and titanium oxide (TiO₂) on stainless steel (SS) were prepared by the radio frequency sputtering method, and the effects of the nanocomposite coating on corrosion protection and antibacterial activities of nanocomposite coated SS were investigated. Scanning electron microscopy was conducted to observe surface morphology of nanocomposite coatings with distinct distribution of grains with the formation on SS substrate. From the electrochemical impedance spectroscopy results, ZrO₂/ZnO/TiO₂ nanocomposite coating showed excellent corrosion protection performance at 37 °C during immersion in simulated body fluid and saliva solution for 12 and 4 weeks, respectively. The impedance of ZrO₂/ZnO/TiO₂ (40/10/50) nanocomposite coated SS exhibited values about 5 orders of magnitude higher than that of uncoated SS with polarization at the low-frequency region. Cell viability of ZrO₂/ZnO/TiO₂ nanocomposite coated SS was examined under mouse fibroblasts culture (L929), and it was observed that the nanocomposite coating improves proliferation through effective cellular attachment compared to uncoated SS. From the antimicrobial activity results, ZrO₂/ZnO/TiO₂ nanocomposite-coated SS showed killing efficiency of 81.2% and 72.4% against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus, respectively.

Removal of Organic Dyes from Water and Wastewater Using Magnetic Ferrite-Based Titanium Oxide and Zinc Oxide Nanocomposites: A Review

Heterogeneous photocatalysis using titanium dioxide (TiO2) and zinc oxide (ZnO) has been widely studied in various applications, including organic pollutant remediation in aqueous systems. The popularity of these materials is based on their high photocatalytic activity, strong photosensitivity, and relatively low cost. However, their commercial application has been limited by their wide bandgaps, inability to absorb visible light, fast electron/hole recombination, and limited recyclability since the nanomaterial is difficult to recover. Researchers have developed several strategies to overcome these limitations. Chief amongst these is the coupling of different semi-conductor materials to produce heterojunction nanocomposite materials, which are both visible-light-active and easily recoverable. This review focuses on the advances made in the development of magnetic ferrite-based titanium oxide and zinc oxide nanocomposites. The physical and magnetic properties of the most widely used ferrite compounds are discussed. The spinel structured material had superior catalytic and magnetic performance when coupled to TiO2 and ZnO. An assessment of the range of synthesis methods is also presented. A comprehensive review of the photocatalytic degradation of various priority organic pollutants using the ferrite-based nanocomposites revealed that degradation efficiency and magnetic recovery potential are dependent on factors such as the chemical composition of the heterojunction material, synthesis method, irradiation source, and structure of pollutant. It should be noted that very few studies have gone beyond the degradation efficiency studies. Very little information is available on the extent of mineralization and the subsequent formation of intermediate compounds when these composite catalysts are used. Additionally, potential degradation mechanisms have not been adequately reported.

Photodegradation of Reactive Red 141 and Reactive Yellow 105 Dyes Using Prepared TiO2 Nanoparticles

The photodegradation of Reactive Red 141 (RR-141) and Reactive Yellow 105 (RY-105) dyes using TiO2 nanoparticles was investigated under UV light irradiation. TiO2 was prepared by sol-gel process and characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) with Energy Dispersive X-ray analysis (EDAX) and FTIR. The effects of operational parameters such as illumination time, catalyst dose, initial concentration and pH of dye solutions on photodegradation by TiO2 have been analyzed. The degradation of the selected dyes followed pseudo-first order reaction according to the Langmuir-Hinshelwood kinetic model.