Effect of annealing on the structure, morphology and photocatalytic activity of surface-fluorinated TiO2 with dominant {001} facets

Photovoltaic Performance of Spherical TiO2 Nanoparticles Derived from Titanium Hydroxide Ti(OH)4: Role of Annealing Varying Temperature

High-quality titanium dioxide (TiO2 or titania) nanoparticles (TiO2NPs) with tailored morphologies are desirable for efficient photovoltaic applications. In this view, some thin films containing spherical TiO2NPs were prepared on indium tin oxide (ITO) and silicon (Si) substrates from titanium hydroxide Ti(OH)4 using the unified sol-gel, spray and spin coating method followed by thermal annealing at different temperatures (in the range of 200–650 °C). Samples were characterized using various analytical tools to determine the influence of annealing temperatures on their structures, morphologies, and optical and photovoltaic characteristics. A field-emission scanning electron microscope (FESEM) and energy-filtered transmission electron microscopy (EFTEM) images of the annealed films displayed the existence of spherical TiO2NPs of average size in the range of 3.2 to 33.94 nm. XRD analysis of the films showed their amorphous nature with anatase and rutile phase. Optical UV-Vis spectral analysis of the annealed films exhibited a decrease in the bandgap energy from 3.84 to 3.24 eV with the corresponding increase of annealing temperature from 200 to 650 °C. The optimum films obtained at 500 and 600 °C were utilized as electron transport layers to fabricate the metal-insulator-semiconductor solar cells. The cells’ power conversion efficiency assembled with the spherical TiO2NPs-enclosed thin films annealed at 500 and 600 °C were 1.02 and 0.28%, respectively. Furthermore, it was shown that the overall properties and photovoltaic performance of the TiO2NPs-based thin films could be improved via thermal annealing.

The bifunctional Lewis acid site improved reactive oxygen species production: a detailed study of surface acid site modulation of TiO2 using ethanol and Br−

Modulation of surface acid sites (SAS) can effectively enhance the efficiency of reactive oxygen species (ROS) production.

Preparation of Ag/TiO2 nanocomposites with controlled crystallization and properties as a multifunctional material for SERS and photocatalytic applications

Ag/TiO₂ nanocomposites with controlled crystallization and properties were prepared by a simple solvothermal method. By using the same raw materials with different ratio and reaction conditions, the morphologies and crystallization of nanocomposites can be tuned. The components of the products were analyzed by TEM and XRD methods respectively. The as-prepared Ag/TiO₂ nanocomposites were used as surface-enhanced Raman spectroscopy (SERS) substrate to be evolved for detection of environmental organic dyes pollutants (CV and RhB) with excellent recyclability. Furthermore, it also showed enhanced catalytic performance of nitrophenol compounds (4-NP). After that, the Ag/TiO₂ nanocomposites were also used as an active substrate and a superior catalyst for reduction of 4-NTP monitored by Raman spectroscopy.