Facile synthesis and characterization of Ag(NP)/TiO2 nanocomposite: Photocatalytic efficiency of catalyst for oxidative removal of Alizarin Yellow

Novel cubical Ag(NP) decorated titanium dioxide supported bentonite thin film in the efficient removal of bisphenol A using visible light

The persistent endocrine-disrupting chemical bisphenol A is posing serious health concerns; hence, it is known to be an emerging and potential water contaminant. The present investigation aims to synthesize novel cubical Ag(NP) decorated titanium dioxide-supported bentonite (Ag/TiO₂@Clay) nanocomposite using a novel synthetic process. The nanocomposite materials were characterized by several analytical methods viz., transmission electron microscopy (TEM), X-ray diffraction (XRD) analyses, energy-dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) and diffuse reflectance spectroscopy (DRS). Further, the photocatalytic removal of bisphenol A was conducted utilizing the thin film catalyst under the LED (light emitting diode; visible light) and UV-A (ultra violet-A) light sources. The parametric studies solution pH (6.0-12.0), pollutant concentrations (1.0-20.0 mg/L), and the interaction of several scavengers and co-existing ions are studied extensively to demonstrate the insights of the removal mechanism. The mineralization of bisphenol A and repeated use of the thin film catalyst showed the potential usage of photocatalysts in the devised large-scale operations. Similarly, the natural matrix treatment was performed to evaluate the suitability of the process for real implications.

Novel nanocomposite thin film in the efficient removal of antibiotics using visible light: Insights of photocatalytic reactions and stability of thin film in real water implications

Novel clay (bentonite) supported Ag⁰ nanoparticles (NPs) doped TiO₂ nanocomposite (Clay/TiO₂/Ag⁰(NPs)) thin film was obtained by using template synthesis method. The nanocomposite material is decorated with cubical Ag⁰(NPs) and utilised successfully in the photocatalytic degradation of tetracycline (TC) and sulfamethazine (SMZ) from aqueous solutions utilizing visible light and UV-A radiations. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), X-ray photoelectron spectroscopy (XPS) analyses were used to characterise the nanocomposite materials. Diffusion reflectance spectroscopy (DRS) was utilised to determine the bandgap energies of the materials and also to confirm that Ag⁰(NPs) was successfully doped with TiO₂. The nanocomposite material showed highly efficient photocatalytic activity for the breaking down of TC/SMZ under visible light irradiation by the enhanced electron-hole separation and adsorption of antibiotics at the vicinity of the catalyst. The oxidative degradation of TC/SMZ were shown to be highly dependent on the pH, initial concentration of TC/SMZ, and various co-existing ions. Reusability test of Clay/Ag⁰(NPs)/TiO₂ nanocomposite revealed that the activity did not decline with repeated use. Treatment of TC and SMZ in real water system further enhanced the application potential of the novel catalysts for the treatment of full-scale wastewater polluted with these antibiotics.

Enhanced visible light photocatalytic performance of a novel FeIn2S4 microsphere/BiOBr nanoplate heterojunction with a Z-scheme configuration

The rational design of heterojunction photocatalysts is an effective way to improve semiconductor photocatalytic activity. The simple solvothermal method was used to successfully prepare visible light-driven FeIn₂S₄ microsphere/BiOBr nanoplate binary heterojunction photocatalysts with varying FeIn₂S₄ contents. The crystal structure, morphology, surface composition, specific surface area, charge separation, and optical properties of the as-prepared photocatalysts were investigated using a variety of analytical methods. In the photocatalytic degradation of rhodamine B, the FeIn₂S₄/BiOBr photocatalysts obtained a degradation efficiency of 96% within 60 min, which was approximately 5.33 and 2.59 times higher than pure FeIn₂S₄ and BiOBr, respectively. Radical trapping experiments and ESR measurements revealed the main active species (·OH, ·O₂^-, and h⁺) produced during photocatalytic degradation. The increased photocatalytic activity was due to the formation of Z-scheme heterojunctions between FeIn₂S₄ and BiOBr, which contributed to the improved effective charge separation of photogenerated charge carriers, augmented specific surface area, and enhanced redox capacity. It is expected that our current study will provide a hopeful way for future environmental remediation research.

A Review on Metal Ions Modified TiO2 for Photocatalytic Degradation of Organic Pollutants

TiO2 is a semiconductor material with high chemical stability and low toxicity. It is widely used in the fields of catalysis, sensing, hydrogen production, optics and optoelectronics. However, TiO2 photocatalyst is sensitive to ultraviolet (UV) light; this is why its photocatalytic activity and quantum efficiency are reduced. To enhance the photocatalytic efficiency in the visible light range as well as to increase the number of the active sites on the crystal surface or inhibit the recombination rate of photogenerated electron–hole pairs electrons, various metal ions were used to modify TiO2. This review paper comprehensively summarizes the latest progress on the modification of TiO2 photocatalyst by a variety of metal ions. Lastly, the future prospects of the modification of TiO2 as a photocatalyst are proposed.