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

Catalysts ◽  
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.

scholarly journals Preparation and Photocatalytic Properties of CdS and ZnS Nanomaterials Derived from Metal Xanthate

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3313 ◽  
Author(s):  
Neli Mintcheva ◽  
Gospodinka Gicheva ◽  
Marinela Panayotova ◽  
Wilfried Wunderlich ◽  
Aleksandr A. Kuchmizhak ◽  
...  
Keyword(s):  
Visible Light ◽  
Band Gap ◽  
Energy Band ◽  
Photocatalytic Properties ◽  
Cubic Phase ◽  
Sulfur Source ◽  
Energy Band Gap ◽  
Simple Method ◽  
Vis Spectroscopy ◽  
Metal Xanthate

In this paper, we report a new, simple method for the synthesis of CdS and ZnS nanoparticles (NPs) prepared in a basic aqueous medium using metal xanthate as the sulfur source. The structure, morphology, size distribution, optical band gap, and photocatalytic properties of the newly obtained nanomaterials were investigated by UV-Vis spectroscopy, X-ray diffraction, and transmission electron microscopy. The results show that both CdS and ZnS crystallized in cubic phase and formed NPs with average sizes of 7.0 and 4.2 nm for CdS and ZnS, respectively. A blue shift of UV-Vis absorbance band and higher energy band gap values were observed for both materials in comparison with their bulk counterparts, which is in accordance with the quantum confinement effect. The as-prepared nanomaterials were tested in visible-light driven photocatalytic decomposition of methylene blue (MB). After irradiation for 180 min, the degradation rate of MB with a concentration of 8 × 10−6 mol/L mixed with a photocatalyst (CdS or ZnS, both 10 mg in 100 mL solution of MB) was found to be 72% and 61%, respectively. The CdS NPs showed better photocatalytic activity than ZnS, which could be explained by their lower energy band gap and thus the ability to absorb light more efficiently when activated by visible-light irradiation.

scholarly journals Band Gap Implications on Nano-TiO2 Surface Modification with Ascorbic Acid for Visible Light-Active Polypropylene Coated Photocatalyst

Nanomaterials ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 599 ◽  
Author(s):  
Chiara D’Amato ◽  
Rita Giovannetti ◽  
Marco Zannotti ◽  
Elena Rommozzi ◽  
Marco Minicucci ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Surface Modification ◽  
Visible Light ◽  
Band Gap ◽  
Tio2 Nanoparticles ◽  
Photoelectron Spectroscopy ◽  
Nano Tio2 ◽  
Alizarin Red ◽  
X Ray ◽  
Visible Light Active

The effect of surface modification using ascorbic acid as a surface modifier of nano-TiO2 heterogeneous photocatalyst was studied. The preparation of supported photocatalyst was made by a specific paste containing ascorbic acid modified TiO2 nanoparticles used to cover Polypropylene as a support material. The obtained heterogeneous photocatalyst was thoroughly characterized (scanning electron microscope (SEM), RAMAN, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL), and Diffuse Reflectance Spectra (DRS) and successfully applied in the visible light photodegradation of Alizarin Red S in water solutions. In particular, this new supported TiO2 photocatalyst showed a change in the adsorption mechanism of dye with respect to that of only TiO2 due to the surface properties. In addition, an improvement of photocatalytic performances in the visible light photodegration was obtained, showing a strict correlation between efficiency and energy band gap values, evidencing the favorable surface modification of TiO2 nanoparticles.

Energy Band Gap Modulation in Nd-Doped BiFeO3/SrRuO3 Heteroepitaxy for Visible Light Photoelectrochemical Activity

2018 ◽  
Vol 11 (1) ◽  
pp. 1655-1664 ◽  
Author(s):  
Kok Hong Tan ◽  
Yun-Wen Chen ◽  
Chien Nguyen Van ◽  
Hongliang Wang ◽  
Jhih-Wei Chen ◽  
...  
Keyword(s):  
Visible Light ◽  
Band Gap ◽  
Energy Band ◽  
Energy Band Gap ◽  
Photoelectrochemical Activity ◽  
Band Gap Modulation

scholarly journals STUDY OF TiO2 NANOPARTICLES’ STRUCTURE USING DENSITY FUNCTIONAL THEORY BASED TIGHT BINDING METHOD

2019 ◽  
Vol 1 (27) ◽  
pp. 79-85
Author(s):  
Hung Thanh Phan
Keyword(s):  
Density Functional Theory ◽  
Band Gap ◽  
Tio2 Nanoparticles ◽  
Energy Band ◽  
Density Functional ◽  
Anatase Phase ◽  
Tight Binding ◽  
Energy Band Gap ◽  
Functional Theory ◽  
Practical Applications

The different structure and size of TiO2 nanoparticles ranging from 0.8 nm to 2.7 nm with two different phases of anatase and rutile were studied by Density  Functional theory based Tight Binding (DFTB) method. The results showed that the stability of the rutile phase was better than that of the anatase phase. Based on calculation of the electronic properties of particles, the energy band gap of rutile particles was comparable to that of bulk structure. In contrast, the energy band gap of the anatase changed irregularly. Moreover, the formation energy that was used for forming the particles was inversely proportional to their size based on computation of energy. The results provided useful instructions for practical applications in fabrication of TiO2 nanoparticles.

N-Doped Titanium Monoxide Nanoparticles with TiO Rock-Salt Structure, Low Energy Band Gap, and Visible Light Activity

2010 ◽  
Vol 22 (12) ◽  
pp. 3704-3711 ◽  
Author(s):  
Pardis Simon ◽  
Bruno Pignon ◽  
Baoji Miao ◽  
Servane Coste-Leconte ◽  
Yann Leconte ◽  
...  
Keyword(s):  
Visible Light ◽  
Band Gap ◽  
Rock Salt ◽  
Energy Band ◽  
Low Energy ◽  
Titanium Monoxide ◽  
Energy Band Gap ◽  
Rock Salt Structure ◽  
Light Activity ◽  
Salt Structure

Cu2O–TiO2 Composite for Photocatalytic Degradation of Benzene and its derivatives Using Visible Light

2021 ◽  
Vol 17 ◽  
Author(s):  
Satya Vijaya Kumar Nune ◽  
Ravi Kumar Golimidi
Keyword(s):  
Visible Light ◽  
Photocatalytic Degradation ◽  
Band Gap ◽  
Tio2 Nanoparticles ◽  
Uv Light ◽  
High Surface ◽  
High Surface Area ◽  
Visible Region ◽  
Copper Ion ◽  
Visible Light Active

Background: Heterostructured nanocomposites have gained huge attention for their catalytic properties lately. A wide array of different visible-light-active photocatalysts (VLAPs) have been extensively studied of the past couple of years to fine tune the band gap of various stable semiconductors. Objective: The current investigation reports the sensitization of TiO2 nanoparticles with nano sized cuprous oxide, a wellstudied p-type semiconductor, which has a relatively narrow band gap ranging between 2.1 eV & 2.6 eV, to obtain a visible light active photocatalyst. Methods: visible-light-active Cu2O–TiO2 nanocomposite synthesized using solvo-thermal technique. The nanocomposite’s structure and size properties were studied using powder diffraction (XRD), electron microscopy (FESEM and HRTEM). Cu2O–TiO2 nanocomposite was tested on benzene, toluene and chlorobenzene in contaminated water, under UV and under visible light, for effective implementation in photocatalytic degradation of volatile organic contaminants. Results: The said nanocomposite was crystalline and found to be 40–50 nm in size. No apparent change in the crystal lattice of TiO2 was observed due to the introduction of copper ion, and the nanocomposite also retained high surface area of 76.28 m2 /g. The efficiency of the Cu2O-TiO2 nanoparticles degradation is studied both under UV light and under visible. Cu2O-TiO2 nanoparticles have achieved 97 – 99% degradation of benzene, 92 – 97% degradation of toluene and 95 – 98% degradation of chlorobenzene in water. Conclusion: The said Cu2O–TiO2 nanocomposite is photo-active and showed an overall 95% degradation within 2 hours of treatment under the visible region.

Visible Light Active Ce-doped TiO2 Nanoparticles for Photocatalytic Degradation of Methylene Blue

2016 ◽  
Vol 13 (1) ◽  
pp. 110-116 ◽  
Author(s):  
Rani P. Barkul ◽  
Farah-Naaz A. Shaikh ◽  
Sagar D. Delekar ◽  
Meghshyam K. Patil
Keyword(s):  
Methylene Blue ◽  
Visible Light ◽  
Photocatalytic Degradation ◽  
Tio2 Nanoparticles ◽  
Doped Tio2 ◽  
Visible Light Active

scholarly journals No Resistive Normal Electrons in Beginning Superconducting States

Mathematics ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1512
Author(s):  
Changho Seo ◽  
Seongsoo Cho ◽  
Je Huan Koo
Keyword(s):  
Band Gap ◽  
Energy Band ◽  
Energy Band Gap

We investigate why normal electrons in superconductors have no resistance. Under the same conditions, the band gap is reduced to zero as well, but normal electrons at superconducting states are condensed into this virtual energy band gap.

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