Fabrication and Evaluation of Visible Light Active TiO2 Photocatalyst by Molten Salt Method

Sputter-deposited TiO2 films with high visible-light photocatalytic activity were successfully realized by a hybrid TiO2/Pt/WO3 film structure with Pt nanoparticles uniformly distributed at the interface of the TiO2 and WO3 films.

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Synthesis of Oxygen Deficient TiO2 for Improved Photocatalytic Efficiency in Solar Radiation

Catalysts ◽

10.3390/catal11080904 ◽

2021 ◽

Vol 11 (8) ◽

pp. 904

Author(s):

Kassim Olasunkanmi Badmus ◽

Francois Wewers ◽

Mohammed Al-Abri ◽

Mohd Shahbaaz ◽

Leslie F. Petrik

Keyword(s):

Solar Radiation ◽

Visible Light ◽

Band Gap ◽

Tio2 Nanoparticles ◽

Energy Band ◽

High Energy ◽

Orange Ii ◽

Tio2 Photocatalyst ◽

Energy Band Gap ◽

Visible Light Active

The photocatalytic activities of TiO2 have been limited mainly to absorbing in the ultraviolet spectrum which accounts for only 5% of solar radiation. High energy band gap and electron recombination in TiO2 nanoparticles are responsible for its limitations as a photocatalyst. An oxygen deficient surface can be artificially created on the titanium oxide by zero valent nano iron through the donation of its excess electrons. A visible light active TiO2 nanoparticle was synthesized in the current investigation through simple chemical reduction using sodium boro-hydride. The physical and textural properties of the synthesized oxygen deficient TiO2 photocatalyst was measured using scanning/ transmission electron microscopy while FTIR, XRD and nitrogen sorption methods (BET) were employed for its further characterizations. Photochemical decoloration of orange II sodium dye solution in the presence of the synthesized TiO2 was measured using an UV spectrophotometer. The resulting oxygen deficient TiO2 has a lower energy band-gap, smaller pore sizes, and enhanced photo-catalytic properties. The decoloration (88%) of orange (II) sodium salt solution (pH 2) under simulated solar light was possible at 20 min. This study highlights the effect of surface oxygen defects, crystal size and energy band-gap on the photo-catalytical property of TiO2 nanoparticles as impacted by nano zero valent iron. It opens a new window in the exploitation of instability in the dopant ions for creation of a visible light active TiO2 photocatalyst.

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Effect of Molten Salts on Synthesis and Upconversion Luminescence of Ytterbium and Thulium-Doped Alkaline Yttrium Fluorides

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.766.34 ◽

2018 ◽

Vol 766 ◽

pp. 34-39 ◽

Cited By ~ 2

Author(s):

Thanataon Pornpatdetaudom ◽

Karn Serivalsatit

Keyword(s):

Visible Light ◽

Molten Salt ◽

Ultraviolet Light ◽

Laser Diode ◽

Molten Salts ◽

Upconversion Luminescence ◽

The Other ◽

Ultraviolet Region ◽

Molten Salt Method ◽

Lower Intensity

Upconversion luminescence materials have recently received attentions because of theirs light conversion ability from infrared into visible and ultraviolet light. In this work, alkaline yttrium fluoride doped by ytterbium and thulium (AYF4: 20%Yb3+, 0.5%Tm3+) were synthesized by molten salt method at 400 °C for 2 hours with different eutectic molten salts, i.e. NaNO3-KNO3, NaNO3-LiNO3, KNO3-LiNO3, and NaNO3-KNO3-LiNO3. Pure hexagonal NaYF4 microrods were successfully synthesized using eutectic NaNO3-KNO3 molten salt. Under 980 nm laser diode excitation, upconversion luminescence in both visible and ultraviolet region was clearly observed. On the other hand, for the use of other eutectic molten salts containing LiNO3, the mixed phases of tetragonal LiYF4 and orthorhombic Y6O5F8 were obtained. These powders emitted only visible light with 10 times lower intensity than the hexagonal NaYF4 microrods synthesized using NaNO3-KNO3.

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