New Insights into the Mechanism of Visible Light Photocatalysis

ABSTRACT: In recent years, the area of developing visible-lightactive photocatalysts based on titanium dioxide has been enormously investigated due to its wide range of applications in energy and environment related fields. Various strategies have been designed to efficiently utilize the solar radiation and to enhance the efficiency of photocatalytic processes. Building on the fundamental strategies to improve the visible light activity of TiO2-based photocatalysts, this Perspective aims to give an insight into many contemporary developments in the field of visible-light-active photocatalysis. Various examples of advanced TiO2 composites have been discussed in relation to their visible light induced photoconversion efficiency, dynamics of electron− hole separation, and decomposition of organic and inorganic pollutants, which suggest the critical need for further development of these types of materials for energy conversion and environmental remediation purposes

Biological effect of silver-modified nanostructured titanium dioxide in cancer

Background/Aim: Nanomedicine is a promising scientific field that exploits the unique properties of innovative nanomaterials, providing alternative solutions in diagnostics, prevention and therapeutics. Titanium dioxide nanoparticles (TiO2NPs) have a great spectrum of photocatalytic antibacterial and anticancer applications. The chemical modification of TiO2optimizes its bioactive performance. The aim of this study was the development of silver modified NPs (Ag/TiO2NPs) with anticancer potential. Materials and Methods: Ag/TiO2NPs were prepared through the sol-gel method, were fully characterized and were tested on cultured breast cancer epithelial cells (MCF-7 and MDAMB-231). The MTT colorimetric assay was used to estimate cellular viability. Western blot analysis of protein expression along with a DNA-laddering assay were employed for apoptosis detection. Results and Conclusion: We show that photo-activated Ag/TiO2NPs exhibited significant cytotoxicity on the highly malignant MDA-MB-231 cancer cells, inducing apoptosis, while MCF-7 cells that are characterized by low invasive properties were unaffected under the same conditions. © 2021 International Institute of Anticancer Research. All rights reserved

Carrier transport in dye-sensitized solar cells using single crystalline TiO<inf>2</inf> nanorods grown by a microwave-assisted hydrothermal reaction

Single crystalline rutile nanorod was grown directly on top of fluorine-doped tin oxide (FTO) substrate via a microwave assisted hydrothermal reaction which dramatically increased a growth rate over a conventional hydrothermal method. In addition, the introduction of thin TiO2 seed layer to FTO substrates promotes heterogeneous nucleation and increases the density. Dye-sensitized solar cells (DSSCs) were fabricated using the rutile nanorods that were differently treated with TiCl4 solution and the carrier transport mechanism in the nanorod-based DSSCs was systematically examined. When the nanorods were treated with TiCl4, more dye was adsorbed on the TiO2 films and the energy conversion efficiency increased to 3.7% for a 2.5 μm thick TiO2 film. Stepped light induced-transient measurement of photocurrent and voltage measurements showed that the role of the nanorods in DSSCs is to increase an electron diffusion coefficient in TiO2 mesoporous films. In contrast to the diffusion coefficient, the lifetime of electron is not dependent on the presence of the nanorods. To explain the experimental observations, we propose a surface diffusion model for electrons that are injected into the rutile nanorods from dye molecules. This surface diffusion may originate from the high crystallinity of nanorods and the homogeneous contact between nanorod and coated nanoparticle layer. © 2011 American Chemical Society