The Influence of Cr Doped TiO2 on the Optical Property and Photocatalytic Activity under Sunlight Irradiation

Pure TiO2 and Cr doped TiO2 (0.1-1.0wt% Cr) nanoparticles were synthesized via sol gel method. This study focuses on narrowing the TiO2 band gap energies in order to enhance the photocatalytic efficiency under visible light. The synthesized samples were characterized by X-Ray diffraction method (XRD), field emmision (FESEM) and also UV-Vis diffuse reflectance spectroscopy (DRS).The photocatalytic activity under sunlight irradiation was demonstrated by photocatalytic decomposition of methylene blue in water using UV/Vis spectrophotometer. The XRD analysis of pure TiO2 and doped TiO2 calcined at 500oC showed a mixture of anatase and rutile phases with decreasing crystallites size from 13.3nm to 11.6nm as the concentration of Cr was increased. The anatase-rutile phase transformation increased from 28.8% to 57.4%. An indication shows that at 0.75wt%, Cr the anatase and rutile phases have equal composition percentage. This study demonstrated that band gap energy of TiO2 was reduced with Cr doping which could enhance the photocatalytic efficiency. Sample containing 1.0wt% exhibit the lowest optical band gap energy at 2.86 eV. The optimum chromium doping concentration was found to be at 0.1 wt% Cr corresponding to band gap energy of 2.87 eV and degradation rate of 84%.

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Sol-Gel Synthesis of Na2Ta4O11 Nanocrystals Showing High Efficient Photocatalytic Performance

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1058.35 ◽

2014 ◽

Vol 1058 ◽

pp. 35-39 ◽

Cited By ~ 1

Author(s):

Yi Guo Su ◽

Xu Yang ◽

Ting Ting Wang ◽

Bao Ling Zhu ◽

Xiao Jing Wang

Keyword(s):

Photocatalytic Activity ◽

Band Gap ◽

Photocatalytic Performance ◽

Diffuse Reflectance Spectroscopy ◽

Sol Gel ◽

Band Gap Energy ◽

Active Species ◽

Gap Energy ◽

High Efficient ◽

Sol Gel Synthesis

Semiconductors showing high efficient photocatalytic activity have attracted great interest, because they provide a potential solution to many environmental pollution problems that humankind is currently facing. This work reports on the sol-gel synthesis of Na2Ta4O11 nanocrystals and its photocatalytic performance toward Red G. The samples were carefully characterized by X-ray diffraction, transmission electron microscopy, UV-vis diffuse reflectance spectroscopy, and the Barrett–Emmett–Teller technique. By modulating the synthetic condition, the sol-gel reaction yielded pure Na2Ta4O11 nanocrystals with diameter of ~32 nm from the peak broadening of (006) plane using Scherrer formula. It is found that the as-prepared Na2Ta4O11 nanocrystals showed a band gap energy of 3.63 eV, which is much smaller than that of Na2Ta4O11 prepared by flux approach. The relative narrowed band gap energy of Na2Ta4O11 nanocrystals may predict superior photocatalytic activity. By careful photocatalytic test, it is found that Na2Ta4O11 nanocrystals showed excellent photocatalytic activity toward Red G. The photocatalytic degradation efficiency was estimated to be 94.0% within a time intervals of 40 minutes. Controlled experiment by adding active species scavengers gave evidence that the degradation of Red G is dominated by the oxidation reaction of the generated O2-∙ active species taking place on the surface of the photocatalyst.

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Optimized Synthesis Temperature and Time to Obtain Crystalline Carbon Nitride with Enhanced Photocatalytic Activity for Phenol Degradation

Indonesian Journal of Chemistry ◽

10.22146/ijc.52345 ◽

2020 ◽

Vol 20 (6) ◽

pp. 1392

Author(s):

Leny Yuliati ◽

Mohd Hayrie Mohd Hatta ◽

Siew Ling Lee ◽

Hendrik Oktendy Lintang

Keyword(s):

Photocatalytic Activity ◽

Specific Surface ◽

Band Gap ◽

Surface Area ◽

Carbon Nitride ◽

Phenol Degradation ◽

Synthesis Temperature ◽

Band Gap Energy ◽

Synthesis Time ◽

Gap Energy

In this work, the crystalline carbon nitride photocatalysts were synthesized by an ionothermal technique with varied synthesis temperature of 500, 550, and 600 °C, and synthesis time of 2, 4, and 6 h. Fourier transform infrared spectra showed the successful formation of the prepared carbon nitrides from their characteristic vibration peaks. X-ray diffraction patterns suggested that the same phase of poly(triazine imide) and heptazine could be observed, but with different crystallinity. The optical properties showed that different temperatures and synthesis time resulted in the different band gap energy (2.72–3.02 eV) as well as the specific surface area (24–73 m2 g–1). The transmission electron microscopy image revealed that the crystalline carbon nitride has a near-hexagonal prismatic crystallite size of about 50 nm. Analysis by high-performance liquid chromatography showed that the best photocatalytic activity for phenol degradation under solar light simulator was obtained on the crystalline carbon nitride prepared at the 550 °C for 4 h, which would be due to the high crystallinity, suitable low band gap energy (2.82 eV), and large specific surface area (73 m2 g–1). Controlling both the temperature and synthesis time is shown to be important to obtain the best physicochemical properties leading to high activity.

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Increasing Rutile Phase Amount in Chromium-Doped Titania by Simple Stirring Approach for Photodegradation of Methylene Blue under Visible Light

Australian Journal of Chemistry ◽

10.1071/ch14565 ◽

2015 ◽

Vol 68 (7) ◽

pp. 1129 ◽

Cited By ~ 6

Author(s):

Pei Wen Koh ◽

Leny Yuliati ◽

Hendrik O. Lintang ◽

Siew Ling Lee

Keyword(s):

Methylene Blue ◽

Visible Light ◽

Band Gap ◽

Rutile Phase ◽

Band Gap Energy ◽

Synthesis Process ◽

Doped Tio2 ◽

Gap Energy ◽

Stirring Time ◽

Doped Titania

The amount of rutile phase in chromium-doped titania photocatalyst was controlled by varying stirring time (0.5–2.0 h) at room temperature during a sol–gel synthesis process. The percentage of rutile phase increased from 15.1 % to 28.6 % when stirring time was prolonged from 0.5 to 1.5 h. Further increases in the stirring time had negligible effect on the rutile phase amount. As evidenced by analyses using diffuse reflectance ultraviolet–visible spectroscopy and X-ray photoelectron spectroscopy, a sufficient stirring time was important for more substitution of Cr3+ for Ti4+ in the lattice, resulting in anatase-to-rutile phase transformation. The formation of more rutile phase in Cr-doped TiO2 not only reduced the band gap energy, but also induced surface defects that retarded electron–hole recombination. It has been demonstrated that the Cr-doped TiO2 prepared with a stirring time of 1.5 h possessed the lowest band gap energy of 1.89 eV, and hence it achieved the highest photodegradation of methylene blue under visible light irradiation.

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Study on Band Gap Energy of F Doped TiO2 Nanotubes

Materials Science Forum ◽

10.4028/www.scientific.net/msf.889.234 ◽

2017 ◽

Vol 889 ◽

pp. 234-238

Author(s):

Mohd Hasmizam Razali ◽

Nur Arifah Ismail ◽

Mahani Yusoff

Keyword(s):

Band Gap ◽

Diffuse Reflectance Spectroscopy ◽

Small Diameter ◽

Ultra Violet ◽

Band Gap Energy ◽

X Ray Diffraction ◽

X Ray ◽

Gap Energy ◽

Transmission Electron ◽

Xrd Patterns

Pure and F doped TiO2 nanotubes was synthesized using simple hydrothermal method. The hydrothermal was conducted using teflon-liner autoclave and maintained at 150oC for 24 hours. The characterization of synthesised product was carried out using x-ray diffraction (XRD), transmission electron microscope (TEM), energy dispersive of x-ray spectroscopy (EDX) and ultra violet – visible light diffuse reflectance spectroscopy (UV-Vis DRS) for band gap measurements. XRD patterns indicated that anatase TiO2 phase was remained after F doping suggested that fluorine was highly dispersed into TiO2 by substituted with O in the TiO2 lattice to formed TiO2-xFx solid solution. Morphology investigation using TEM found out small diameter of nanotubes structure within 8 – 10 nm of pure and F doped TiO2 nanotubes. The band gap energy (Eg) of both nanotubes samples were almost similar proposing that F doping does not modify the band gap energy.

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Synthesis and Characterization Titanium Dioxide (TiO2) Doped Vanadium(V) Using Solid State Method

ALCHEMY ◽

10.18860/al.v4i1.3143 ◽

2015 ◽

Vol 4 (1) ◽

Author(s):

Khusnan Mustofa ◽

Nur Aini ◽

Susi Nurul Khalifah

Keyword(s):

Titanium Dioxide ◽

Solid State ◽

Band Gap ◽

Diffuse Reflectance Spectroscopy ◽

Synthesis Method ◽

Band Gap Energy ◽

Solid State Method ◽

Gap Energy ◽

Wavelength Absorption ◽

State Method

TiO2 Anatase activities should be increased from the UV to the visible light photocatalytic activity of TiO2 to increase anatas. One efforts to optimize TiO2 anatase activity is doping by using dopant vanadium(V). Synthesis method which is used in this research is a solid reaction method. The steps being taken in this methods include grinding and heating at high temperatures. Dopant concentrations of vanadium(V) which are used in the research was 0.3%, 0.5% and 0.7%. and the characterization used is X-ray diffraction and UV-Vis Diffuse Reflectance Spectroscopy. The result shows that there are a changing of particle size, band gap energy, and absorption of TiO2 anatas wavelength because of dopan vanadium(V) addition. While TiO2’s structure does not change. The crystal sizes of each TiO2 without doping, V-TiO2 0,3%, 0,5% and 0,7% are 53.21 nm, 47.67 nm, 79.65 nm dan 68.99 nm. Band gap energy of each TiO2 without doping, V-TiO2 0,3%, 0,5% dan 0,7% are 3.309 eV, 3.279 eV, 3.270 eV and 3.259 eV. While wavelength absorption of each TiO2 without doping, V-TiO2 0,3%, 0,5% and 0,7% are 374.9 nm, 378.4 nm, 379.5 nm and 380.8 nm. Keywords: Synthesis, titanium dioxide, vanadium(V), solid state method

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Automated method for the determination of the band gap energy of pure and mixed powder samples using diffuse reflectance spectroscopy

Heliyon ◽

10.1016/j.heliyon.2019.e01505 ◽

2019 ◽

Vol 5 (4) ◽

pp. e01505 ◽

Cited By ~ 26

Author(s):

A. Escobedo-Morales ◽

I.I. Ruiz-López ◽

M.deL. Ruiz-Peralta ◽

L. Tepech-Carrillo ◽

M. Sánchez-Cantú ◽

...

Keyword(s):

Band Gap ◽

Diffuse Reflectance ◽

Diffuse Reflectance Spectroscopy ◽

Reflectance Spectroscopy ◽

Band Gap Energy ◽

Mixed Powder ◽

Gap Energy ◽

Automated Method ◽

Powder Samples

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Dielectric, optical and enhanced photocatalytic properties of CuCrO2 nanoparticles

RSC Advances ◽

10.1039/c6ra26888a ◽

2017 ◽

Vol 7 (44) ◽

pp. 27549-27557 ◽

Cited By ~ 33

Author(s):

Tokeer Ahmad ◽

Ruby Phul ◽

Parvez Alam ◽

Irfan H. Lone ◽

Mohd. Shahazad ◽

...

Keyword(s):

Methylene Blue ◽

Band Gap ◽

Surface Area ◽

Band Gap Energy ◽

Catalytic Degradation ◽

Photocatalytic Properties ◽

Sunlight Irradiation ◽

Gap Energy ◽

Precursor Route ◽

Citrate Precursor

Delafossite CuCrO2 nanoparticles with band gap energy of 3.09 eV and surface area of 235 m2 g−1 were prepared by citrate precursor route showed enhanced catalytic degradation of methylene blue in H2O under the sunlight irradiation.

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Structured ZnO films: Effect of copper nitrate addition to precursor solution on topography, band gap energy and photocatalytic activity

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/175/1/012042 ◽

2017 ◽

Vol 175 ◽

pp. 012042 ◽

Cited By ~ 1

Author(s):

S Heinonen ◽

J-P Nikkanen ◽

A Kaleva ◽

L Hyvärinen ◽

E Levänen

Keyword(s):

Photocatalytic Activity ◽

Band Gap ◽

Precursor Solution ◽

Copper Nitrate ◽

Band Gap Energy ◽

Zno Films ◽

Gap Energy ◽

Nitrate Addition ◽

Effect Of Copper

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Photocatalytic Hydrogen Production from Water on Ga, Sn-Doped ZnS under Visible Light Irradiation

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.925.200 ◽

2014 ◽

Vol 925 ◽

pp. 200-204

Author(s):

Leny Yuliati ◽

Melody Kimi ◽

Mustaffa Shamsuddin

Keyword(s):

Photocatalytic Activity ◽

Hydrogen Production ◽

Visible Light ◽

Band Gap ◽

Visible Light Irradiation ◽

Absorption Edge ◽

Band Gap Energy ◽

Light Irradiation ◽

Photocatalytic Hydrogen Production ◽

Gap Energy

Zinc sulfide (ZnS) has been reported to act as a photocatalyts to reduce water to hydrogen. However, ZnS could not work under visible light irradiation due to its large band gap energy. In order to improve the performance of ZnS, Ga and Sn were doped to ZnS. The series of Ga (0.1),Sn (x)-ZnS with various amounts of Sn (x) was prepared by hydrothermal method. XRD patterns suggested that the addition of Ga might reduce the crystallinity of ZnS, suggesting that Ga might inhibit the crystal growth or agglomeration of ZnS. On the other hand addition of Sn did not much affect the structure of the Ga (0.1)-ZnS. The DR UU-visible spectra confirmed the red shift of the absorption edge with the addition of Ga due to the reduced band gap energy, while the addition of Sn did not much shift the absorption edge of the Ga (0.1)-ZnS to longer wavelength. FESEM images showed that all the prepared samples have sphere-shaped particles and no remarkable change was observed with the addition of Ga or Sn. The photocatalytic hydrogen production from water was carried out at room temperature in the presence of sacrificial agent under visible light irradiation. While ZnS did not show activity under visible light, all the prepared Ga (0.1)-ZnS and Ga (0.1),Sn (x)-ZnS samples exhibited photocatalytic activity for hydrogen production. The highest hydrogen production was achieved on Ga (0.1),Sn (0.01)-ZnS, which activity was ca. three times higher than that of the single doped Ga (0.1)-ZnS. This study clearly showed that Sn acted as a good co-dopant to increase the photocatalytic activity of Ga (0.1)-ZnS for hydrogen production from water under visible light irradiation.

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