scholarly journals Structure and photocatalytic activity of Ti1−X MX O2 (M = Zr, Co and Mo) synthesized by pulverized solid state technique

2010 ◽  
Vol 8 (2) ◽  
pp. 453-460 ◽  
Author(s):  
S. Santhosh ◽  
S. Swetha ◽  
Geetha Balakrishna
Keyword(s):  
Photocatalytic Activity ◽  
Light Exposure ◽  
Degradation Process ◽  
Xrd Analysis ◽  
Band Gap Energy ◽  
Alizarin Red ◽  
Doped Tio2 ◽  
Edx Analysis ◽  
Diffraction Patterns ◽  
Metal Doped

AbstractA set of transition metal doped nanosized TiO2 particles with anatase structure were synthesized by the pulverization method and their ability to photocatalytically degrade the dye Alizarin Red S was investigated. Characterization of the Zr-, Co- and Mo-doped photocatalysts was conducted with the aid of XRD, SEM, EDX, TEM, BET and spectral analysis. X-ray diffraction patterns did not reflect the appearance of any peaks due to dopants, however dopants were observed in SEM-EDX analysis. Particle sizes were in the range of 25 nm as per TEM and XRD analysis. Upon doping, a prominent decrease in surface area was observed. The percentage composition of each of the dopants was confirmed by EDX analysis. Doped samples depicted many mid-bands in the Kubelka Munk plots due to d-d transition of dopants. Experiments were conducted to compare the photocatalytic activity under identical UV and solar light exposure. Zr-doped TiO2 at the molecular scale exhibited better photocatalytic activity in degradation of Alizarin, with a lower band-gap energy that can respond to visible light. However, Co- and Mo-doped TiO2 appeared to suppress the photoactivity. A rise in the number of mid-bands causing effective separation or recombination of charge carriers strongly influences the rate of the degradation process.

Cr Doped TiO2 Supported on TUD-1 Photocatalyst for Dye Photodegradation

2014 ◽  
Vol 69 (5) ◽  
Author(s):  
Ooi Yee Khai ◽  
Leny Yuliati ◽  
Siew Ling Lee
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Xrd Analysis ◽  
Bandgap Energy ◽  
Doped Tio2 ◽  
Visible Light Driven ◽  
Synthesized Materials

New visible light driven photocatalysts of 1 mol% Cr doped TiO2 supported on TUD-1 have been successfully synthesized. The Cr-TiO2/xTUD-1 (x = 10, 20, 30, 40 and 50) photocatalysts were prepared via surfactant-free sol-gel method followed by wet impregnation procedures. XRD analysis revealed that both TiO2 and Cr were incorporated in the highly porous siliceous matrix. FTIR analysis showed the existence of Si-O-Ti in all the materials. As observed, tetrahedral-coordinated Ti species were dominant in Cr-TiO2/10TUD-1, Cr-TiO2/20TUD-1 and Cr-TiO2/30TUD-1. Meanwhile, octahedral- coordinated Ti species were the dominant species in Cr-TiO2/40TUD-1 and Cr-TiO2/50TUD-1. It has been demonstrated that the amount of TUD-1 as photocatalyst support affected the wavelength response and the bandgap energy of the resulting materials. All the materials have bandgap energy of ~2.9 eV. The photocatalytic performance of the synthesized materials was tested out in dye photodegradation under visible light irradiation at 298 K for 5 hours. Results showed that all Cr-TiO2/TUD-1 materials had higher photocatalytic activity than that of Cr-TiO2. This could be explained by the high surface area and porosity provided by TUD-1 in enhancing the adsorption and diffusivities of the dye molecules, hence leading to the promising photocatalytic activity. Among the materials prepared, Cr-TiO2/30TUD-1 appeared as the most superior photocatalyst which gave the highest dye photodegradation.

Novel TiO2 nanocatalysts for wastewater purification: tapping energy from the sun

2006 ◽  
Vol 54 (8) ◽  
pp. 47-54 ◽  
Author(s):  
Y. Liu ◽  
J. Li ◽  
X. Qiu ◽  
C. Burda
Keyword(s):  
Light Exposure ◽  
Nitrogen Concentration ◽  
Visible Region ◽  
Band Gap Energy ◽  
Acid Orange 7 ◽  
Wastewater Purification ◽  
Doped Tio2 ◽  
Photocatalytic Activities ◽  
Catalytically Active ◽  
Degussa P25

Water treatment using TiO2 semiconductor as a durable heterogeneous photocatalyst has been the focus of environmentalists in recent years. Currently, we developed an inexpensive and highly efficient approach for synthesizing nitrogen-doped TiO2 with lower band-gap energy that can respond to visible light. Doping on the molecular scale led to an enhanced nitrogen concentration of up to 21.8%. Reflectance measurements showed the synthesized N-doped TiO2 nanoparticles are catalytically active with the absorbance that extends into the visible region up to 600 nm. The water purification potential of this new class of compound was evaluated by studying the photodegradation of Acid Orange 7 (AO7) and E. coli. Experiments were conducted to compare the photocatalytic activities of N-doped TiO2 nanocatalysts and commercially available Degussa P25 power under identical solar light exposure. N-doped TiO2 demonstrated superior photocatalytic activities in both chemical compound degradation and bactericidal reactions. The result of this study shows the potential of applying new generations of catalyst for wastewater purification and disinfection.

Investigation of photocatalytic activity of metal-doped TiO2 nanoparticles prepared by Pechini method

2012 ◽  
Vol 64 (3) ◽  
pp. 734-742 ◽  
Author(s):  
Adriane V. Rosario ◽  
Wania A. Christinelli ◽  
Roberta N. Barreto ◽  
Ernesto C. Pereira
Keyword(s):  
Photocatalytic Activity ◽  
Tio2 Nanoparticles ◽  
Pechini Method ◽  
Doped Tio2 ◽  
Metal Doped

Characterization and Photocatalytic Properties of Transition Metal Doped TiO2 and Nanocomposite TiO2 Powders Synthesized by Mechanical Alloying

2007 ◽  
Vol 119 ◽  
pp. 195-198
Author(s):  
Dong Hyun Kim ◽  
Ha Sung Park ◽  
Jae Han Jho ◽  
Wheung Whoe Kim ◽  
Sun Jae Kim ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Photocatalytic Activity ◽  
Transition Metal ◽  
Mechanical Alloying ◽  
Rutile Phase ◽  
Alloyed Powder ◽  
Doped Tio2 ◽  
Average Grain Size ◽  
Xrd Patterns ◽  
Metal Doped

Transition metal doped TiO2 (Ni, Fe, Cu) and nanocomposite TiO2 powders with rutile phase were synthesized by mechanical alloying and heat treatment, and were characterized by XRD, TEM, UV-DRS, and PL (Photoluminescence). Photocatalytic activity was also investigated with the degradation rate of 4-chlorophenol and measured by total organic carbon analyzer. TEMEDP and XRD patterns showed that the transition metal doped powders (only alloyed powder) were in the form of rutile phase with the particle size of 20-30 nm. The average grain size of transition metal doped powders was in the range of less than 10 nm. However, after heat treatment, the alloyed powder formed composite of the titanate and rutile phase. The UV-DRS and PL investigation showed that Ni doped 8 wt% nanocomposite TiO2 had the higher wavelength range (600-660 nm) (2.0-1.9 eV) than that of the commercial P-25 powder(380-400 nm) by Degussa Co. indicating that the Ni 8 wt% doped nanocomposite TiO2 shifted the absorption into the visible light region and thus, enhanced the photocatalytic activity. Further, these results agreed well with TOC investigation. Formation of titanate in transition metal doped TiO2 due to heat treatment was found to control the grain growth of nano-sized TiO2 and to enhance its thermal stability at high temperature.

scholarly journals Effects of photocatalytic activity of metal and non-metal doped Tio2 for Hydrogen production enhancement - A Review

2018 ◽  
Vol 1027 ◽  
pp. 012006 ◽  
Author(s):  
Siti Nur Aqilah Sulaiman ◽  
Mohamad Zaky Noh ◽  
Nurul Nadia Adnan ◽  
Noriah Bidin ◽  
Siti Noraiza Ab Razak
Keyword(s):  
Photocatalytic Activity ◽  
Hydrogen Production ◽  
Doped Tio2 ◽  
Metal Doped

scholarly journals Stable CuCrO2 nanoparticles - ZnO fibres p-n heterostructure system for effective photocatalytic activity

2019 ◽  
Vol 13 (2) ◽  
pp. 189-201 ◽  
Author(s):  
Elif Baylan ◽  
Hasan Akyildiz ◽  
Ozlem Yildirim
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Uv Light ◽  
Light Exposure ◽  
Band Gap Energy ◽  
Blue Dye ◽  
Nanoparticle Dispersion ◽  
K Value ◽  
Composite Photocatalyst ◽  
Visible Light Active

Heterostructured photocatalysts were fabricated by coupling electrospun n-type ZnO fibres and hydrothermally derived p-type CuCrO2 nanoparticles. The effect of the amount of CuCrO2 nanoparticles on the photocatalytic activity of the heterostructured photocatalyst was systematically investigated. The formation of the heterojunctions between the two semiconductors was revealed via detailed XRD, XPS, TEM and optical property measurements. The experimental results indicated that the optimal CuCrO2 amount in the composite photocatalyst was 1.0wt.% due to the optimum doping and surface coverage, higher absorption onset edge, larger absorption intensity and optimum band gap energy. This composite photocatalyst, fabricated by drop casting of CuCrO2 nanoparticle dispersion on ZnO fibres, displayed 30% higher rate constant (k) value compared to the pure ZnO fibres in the degradation of methylene blue dye molecules and reached 93.4% decomposition in 1 h under UV-visible light exposure. The obtained results are highly encouraging in comparison to only UV/light active p-n heterostructured photocatalysts previously reported in literature. Therefore, we believe that the proposed approach here opened the way for simple synthesis of highly-efficient visible light active heterostructured semiconductor photocatalyst systems.

scholarly journals CdS Loaded Activated Carbon: An Efficient, Solar Light Driven Photocatalyst for RhB Dye Degradation

2019 ◽  
Vol 35 (3) ◽  
pp. 1037-1044
Author(s):  
Sagar Kande ◽  
Udhav Ghoshir ◽  
Jayshree Khedkar ◽  
Anil Gambhire
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Activated Carbon ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance Spectroscopy ◽  
Dye Degradation ◽  
Xrd Analysis ◽  
Band Gap Energy ◽  
X Ray ◽  
Adsorption Desorption

A series of novel photocatalyst with CdS loaded on activated carbon (xAC/CdS) were successfully synthesized by a simple hydrothermal method. The activated carbon content was varied between 0-7 wt. %. The prepared photocatalysts were characterized by X-ray diffraction, scanning electron microscopy with EDX, transmission electron microscopy, X-ray photoelectron spectroscopy, UV-Vis diffuse reflectance spectroscopy, N2 adsorption-desorption analysis and photoluminescence spectroscopy. The photocatalytic activity of as-synthesized photocatalysts was studied for RhB dye degradation under natural sunlight irradiation. XRD analysis assigned both cubic and hexagonal morphology for xAC/CdS photocatalysts. The UV-vis DRS studies showed that loading of CdS on activated carbon enhances its visible light absorption with decrease in band gap energy. The lowest photoinduced e/h pair recombination rate in 3wt% AC/CdS results in optimum photocatalytic activity as revealed by photoluminescence study. The enhancement in dye degradation ability (̴ 11 times) of prepared photocatalysts can be attributed to synergistic effect of CdS and activated carbon.

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

2016 ◽  
Vol 13 (1) ◽  
pp. 99
Author(s):  
Siti Zulaikha Suhaili ◽  
Muhamad Kamil Yaakob ◽  
Siti Irma Yuana Saaid ◽  
Umi Sarah Jais
Keyword(s):  
Photocatalytic Activity ◽  
Band Gap ◽  
Diffuse Reflectance Spectroscopy ◽  
Diffraction Method ◽  
Band Gap Energy ◽  
Pure Tio2 ◽  
Photocatalytic Efficiency ◽  
Sunlight Irradiation ◽  
Doped Tio2 ◽  
Gap Energy

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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