Dye-sensitized solar cells (DSCs) are promising next-generation alternatives to conventional silicon-based photovoltaic devices owing to their low manufacture cost. In this presentation, we will discuss the strategy for improving η of DSCs.

Highly Efficient Dye-Sensitized Solar Cells

Recently, an increase in the production of intelligent nanomaterials has been reported for the application of solid surface coating. These nanomaterials provide a wide number of functionalities suc...

https://journals.sagepub.com/doi/pdf/10.1177/1847980420909188

Preparation of modified paints with nano-structured additives and its potential applications:

A novel nanohybrid composite of TiO2, SiO2, γ-Fe2O3, and reduced graphene oxide (TiO2@Si:Fe:rGO) is fabricated by the sol-gel method. The properties of the coated film were examined by structural and self-cleaning analyses using simulated discoloration/soiling and roofing tests. The fabricated transparent TiO2@Si:Fe:rGO composite showed excellent photoactivity and wettability, behaving well in self-cleaning applications. The addition of SiO2 improved the crystalline structure and surface hydroxylation of TiO2 nanoparticles. γ-Fe2O3 decreased the recombination rate of e-/h+ pairs, and significantly improved photocatalytic activity under visible light. Moreover, rGO sheets as excellent electron acceptors and transporters also reduced recombination, as well as affected wettability, achieving superhydrophilicity under irradiation. The coated substrate showed excellent resistance to simulated acid rain and significantly preserved the substrate from soiling in roofing tests.

Heterostructured TiO2/SiO2/γ-Fe2O3/rGO Coating with Highly Efficient Visible-Light-Induced Self-Cleaning Properties for Metallic Artifacts.

An argon plasma jet was sustained in open air and characterized for its chemical composition. The optically characterized plasma jet was used to treat industrial wastewater containing mixed textile dyes and heavy metals. Since plasma jet produces UV-radiations, the photocatalytic TiO2 was used to enhance plasma treatment efficiency especially for degradation of dyes. Mixed anatase and rutile phases of TiO2 (5.2–8.5 nm) were produced through surfactant assisted sol–gel approach. The emission spectrum confirmed the presence of excited argon, OH, excited nitrogen, excited oxygen, ozone and nitric oxide in the plasma jet. The spectral lines of excited Ar, NO, O3, OH−, N2, $${\mathrm{N}}_{2}^{+}$$
 , O, $${\mathrm{O}}_{2}^{+}$$
 and O+ species were observed at wavelength of 695–740 nm, 254.3 nm, 307.9 nm, 302–310 nm, 330–380 nm, 390–415 nm, 715.6 nm, 500–600 nm and 400–500 nm. These reactive species decompose the organic pollutants and separate the heavy metals from the water samples. The conductivity of plasma exposed water samples increased while pH and hardness decreased. The atomic absorption spectrophotometry analysis confirmed the presence of heavy metals in the samples, which were effectively removed through plasma treatment. Finally, the effect of plasma treatment on Staphylococcus aureus strains was more pronounced than Escherichia coli strains.

/pdf/optical-characterization-of-non-thermal-plasma-jet-energy-47chgmntyf.pdf

Optical characterization of non-thermal plasma jet energy carriers for effective catalytic processing of industrial wastewaters

The influence of the crystalline phase and agglomeration degree of TiO2 nanoparticles embedded in an amorphous SiO2 matrix on the photocatalytic hydroxyl radical formation and bacterial inactivation was established in TiO2/SiO2 composite coatings, fabricated using a low-temperature, simple, and inexpensive technique. The photocatalytic hydroxyl radical formation was studied on TiO2/SiO2 coatings in presence of hole, electron, superoxide radical, and hydrogen peroxide scavengers, which can be present in bulk solution during wastewater disinfection. From the variation of rate constants for hydroxyl radical formation in the presence of each scavenger, we have established a relationship between hydroxyl radicals’ formation and a charge carrier transfer mechanism between defect levels in SiO2 and TiO2 embedded nanoparticles by a simple spectroscopic method. This way, a final correlation between hydroxyl radical generation, crystalline phase, agglomeration degree, and bacteria inactivation has been obtained, thus complementing the lack of mechanisms behind the photocatalytic activity in TiO2/SiO2 composites.

Influence of selected reactive oxygen species on the photocatalytic activity of TiO2/SiO2 composite coatings processed at low temperature

TiO2 sol was produced by the sol-gel method through the hydrolysis and the aging of tetrabutyl titanate and the TiO2 film was obtained by dipping and uniform lifting of the acid-treated and ultrasound-treated clean glass slides into the TiO2 sol followed by aging, drying, and calcination. The effect of the hydrolysis control agents to the formed sol was researched and the crystalline state, the morphology, and the photocatalytic properties of the products after calcination were characterized. The structural morphology, the contact angles before and after illumination, and the self-cleaning properties of the TiO2 film were characterized as well. The results showed that by using acetylacetone as the hydrolysis control agent, the formed TiO2 sol had relatively high stability. The product after the calcination of the TiO2 sol was of single anatase type with crystalline size of 18–20 nm and it could degrade nearly 100% of methylene blue after 90 min illumination. The formed TiO2 film is compact, continuous, smooth, and had the properties of super-hydrophilicity (after 30 min illumination due to its contact angle decreasing from 21° to nearly 0°) and anti-fogging capability, which indicated its excellent self-cleaning property.

The Preparation of TiO2 Film by the Sol-Gel Method and Evaluation of Its Self-Cleaning Property

In order to improve the dispersion of nano-TiO2 particles and enhance its self-cleaning properties, including photocatalytic degradation of pollutants and surface hydrophilicity, we prepared nano-TiO2-coated SiO2 microsphere composite self-cleaning materials (SiO2–TiO2) by co-grinding SiO2 microspheres and TiO2 soliquid and calcining the ground product. The structure, morphology, and self-cleaning properties of the SiO2–TiO2 were characterized. The characterization results showed that the degradation efficiency of methyl orange by SiO2–TiO2 was 97%, which was significantly higher than that obtained by pure nano-TiO2. The minimum water contact angle of SiO2–TiO2 was 8°, indicating strong hydrophilicity and the good self-cleaning effect. The as-prepared SiO2–TiO2 was characterized by the nano-TiO2 particles uniformly coated on the SiO2 microspheres and distributed in the gap among the microspheres. The nano-TiO2 particles were in an anatase phase with the particle size of 15–20 nm. The nano-TiO2 particles were combined with SiO2 microspheres via the dehydroxylation of hydroxyl groups on their surfaces.

https://www.mdpi.com/2079-4991/7/11/367/pdf

Tongrong Deng

Papers

The Preparation of TiO2 Film by the Sol-Gel Method and Evaluation of Its Self-Cleaning Property

Preparation of Nano-TiO2-Coated SiO2 Microsphere Composite Material and Evaluation of Its Self-Cleaning Property

Effect of calcination temperature on the structure and properties of SiO2 microspheres/nano-TiO2 composites