scholarly journals Easy Synthesis Method of MoS2/TiO2 Nanostructure with Great Performance of Catalytic Activity Under Visible Light

In this study, TiO2 nanoparticles modified with MoS2 were synthesized using the low temperature hydrolysis method. Samples of pure TiO2 and samples of MoS2 /TiO2 were prepared using different amounts of MoS2 (1.0% and 10.0% by weight). The samples were annealed at 500°C and 700°C and characterised by ICP-AES, XRD, Raman, FT-IR, TG, XPS and DR-UV-Vis spectroscopy. The results suggest that the MoS2 added during synthesis is a satisfactory source of Mo to produce doping of the TiO2 structure. In addition, the transformation of anatase phase to rutile is delayed when the concentration of Mo incorporated into the structure increases. Finally, the effectiveness of the synthesized MoS2 /TiO2 samplesused as photocatalyst for the photodegradation of methylene blue dye under visible light irradiation was investigated. TiO2 doped with MoS2 was shown to improve the degradation of methylene blue under visible light. There was found to be an optimal temperature and level of doping to achieve improved photocatalytic activity, in our case 10.0% MoS2 /TiO2 at 700°C.

2018 ◽  
Author(s):  
azadeh ebrahimian pirbazari ◽  
Pejman Monazzam ◽  
Behnam Fakhari Kisomi

In this work, TiO2 nanoparticles containing different amounts of cobalt were synthesized by sol-gel method using titanium (IV) isopropoxide and cobalt chloride as titanium and cobalt precursors, respectively. X-ray diffraction (XRD) results showed prepared samples include 100% anatase phase. The presence of cobalt in TiO2 nanoparticle network was established by XRD, scanning electron microscopy equipped with energy dispersive X-ray microanalysis (SEM-EDX), Fourier transform infrared (FT-IR) and N2 physisorption techniques. The increase of cobalt doping enhanced redshif in the diffuse reflectance spectra. The photocatalytic activity of the prepared samples was tested for degradation of methylene blue (MB) as a model of dye. Although the photocatalytic activity of pure TiO2 was found to be higher than that of Co/TiO2 samples under UV irradiation, the presence of 0.24% cobalt dopant in TiO2 nanoparticles resulted in a photocatalyst with the highest activity under visible light


2018 ◽  
Vol 2017 (1) ◽  
pp. 184-193 ◽  
Author(s):  
Desireé M. de los Santos ◽  
Sara Chahid ◽  
Rodrigo Alcántara ◽  
Javier Navas ◽  
Teresa Aguilar ◽  
...  

Abstract Photodegradation processes are of great interest in a range of applications, one of which is the photodecomposition of pollutants. For this reason, analysing nanoparticles that improve the efficiency of these processes under solar radiation are very necessary. Thus, in this study, TiO2 was doped with Mo and Cu using low-temperature hydrolysis as the method of synthesis. Pure TiO2 and x%MoS2/Cu/TiO2 nanoparticles were prepared, where x is the theoretical quantity of MoS2 added (0.0%, 1.0%, 5.5%, 10.0%), setting the nominal quantity of Cu at 0.5 wt.%. The samples obtained were characterized by X-ray diffraction, Raman spectroscopy, X-ray electron spectroscopy and UV-Vis spectroscopy in diffuse reflectance mode. The results suggest that the TiO2 structure was doped with the Mo6+ and Cu2+ ions in the position of the Ti4+. The x%MoS2/Cu/TiO2 samples presented lower band gap energy values and greater optical absorption in the visible region than the pure TiO2 sample. Lastly, the photocatalytic activity of the samples was assessed by means of the photodegradation of methylene blue under visible light. The results show that when the quantity of Mo in the co-doped samples increased (x%MoS2/Cu/TiO2) there were significant increases of up to 93% in the photocatalytic activity.


2017 ◽  
Vol 757 ◽  
pp. 88-92
Author(s):  
Cheewita Suwanchawalit ◽  
Kamonchanok Roongraung ◽  
Supat Buddee ◽  
Sumpun Wongnawa ◽  
Avinash Patil

Silver-modified bismuth vanadate (Ag-BiVO4) photocatalysts were easily prepared via the co-precipitation method. The effects of silver contents on the chemical properties of BiVO4 were evaluated. The prepared Ag-BiVO4 samples were characterized by several techniques such as X-ray diffractometry (XRD), scanning electron microscopy (SEM), and diffused reflectance UV-Vis spectroscopy (DRS). The mixed phase of monoclinic scheetlite structure and characteristic peaks of silver particles were found. Silver contents strongly affect the morphology of the prepared Ag-BiVO4 samples. DRS spectra revealed that the synthesized Ag-BiVO4 samples exhibited strong absorption in the visible region. The absorption in the visible zone is responsible for the high photocatalytic activity of Ag-BiVO4 under visible light irradiation. The photocatalytic degradation of methylene blue under visible light irradiation was studied using the BiVO4 as photocatalysts. The photocatalytic results reveal that the prepared Ag-BiVO4 samples could degrade the methylene blue dye.


2020 ◽  
Vol 16 ◽  
Author(s):  
Radhakrishna S. Sutar ◽  
Rani P. Barkul ◽  
Meghshyam K. Patil

Background: Different photocatalysts such as TiO2, ZnO, WO3 have been used for degradation of organic pollutants. However, these materials having some limitations, which has been affected the catalytic efficiency in the various transformations. The composites of these materials with other oxide can produce better results by tuning structural as well as optoelectrical properties. The composite of TiO2 with ZrO2 has attracted attention due to their use in different areas as ZrO2 and TiO2 have similar physicochemical features. Methods: This research contain the preparation of ZrO2-TiO2 nanocomposites by hydrothermal method and analysis of photocatalytic activity for degradation of methylene blue and mixture of dyes under visible light irradiation. Results: Physicochemical characterization of ZrO2-TiO2 nanocomposites has been studied by using different techniques. Prepared catalysts has shown anatase phase of TiO2 and tetragonal phase of ZrO2. XRD, FESEM and HRTEM have supported the nanocrystalline nature of the composites. The photocatalytic activity of composites and bare TiO2 samples were demonstrated for the degradation of methylene blue dye. Enhanced activity has been shown by composite having Ti:Zr 3:1 molar proportion i.e., Ti3Zr. Effect of concentration of methylene blue, pH of solution, catalyst loading has been studied by using Ti3Zr. Also, degradation of mixture of three dyes namely methylene blue, rhodamine B and methyl orange has been studied. Conclusion: In summary, prepared zro2-tio2 composites found to be nanocrystalline and visible light active. these catalysts has shown activity for photocatalytic degradation of methylene blue and mixture of dyes.


2020 ◽  
Vol 5 (1) ◽  
pp. 36-46 ◽  
Author(s):  
Shubha Pranesh ◽  
Jayalakshmi Nagaraju

Background: The cost of effluent treatment is not affordable by small scale industries especially in developing countries. Hence the effluent is discharged without treatment into water bodies. The dyes do not degrade easily and possess a major concern to be addressed. The aquatic life is highly affected and also leads to bio magnification of the chemicals through the food chain. Objective: To synthesize a ternary hybrid structure for enhanced photocatalytic activity under visible light. It is intended to reduce toxicity caused by dyeing units. Methods: Synthesized nanomaterials are characterized and used as photocatlyst for the degradation of methylene blue. In degradation experiment known weight of catalyst was added to known volume of an aqueous solution of dye at various concentrations. The solutions are aerated in dark for about 30 min. At the time of irradiation of light, known aliquot of the aqueous mixture was collected at an interval of constant time each from the reaction solution. The catalyst in the mixture was separated by centrifuging the mixture and absorbance was measured. The % of degradation of the dye can be determined knowing initial and final dye concentration. Result: Heterostructures are characterized with analytical tools such as X-ray diffraction, Fourier transform infrared spectroscopy. Band gap of photocatlyst is calculated by application of UV-Vis spectroscopy. Morphology is seen using scanning electron microscopy and transmission electron microscopy. Distribution of constituent structures is observed with energy-dispersive X-ray (EDX) spectroscopy. The structures are used for photocatalytic degradation of methylene blue dye solution under UV and visible light irradiation. Heterostructures showed best performance under visible light. Conclusion: The ternary hybrid nanostructure ZnO-MnO2-Gd2O3 was effectively prepared by a simple solution combustion method. The ternary compound shows wide range of absorption by expanding absorption band both in UV and visible regions. Structures showed better catalytic property under visible light.


Coatings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1150
Author(s):  
Jothi Ramalingam Rajabathar ◽  
Hamad A. Al-Lohedan ◽  
Selvaraj Arokiyaraj ◽  
Zuheir A. Issa ◽  
Chandra Sekhar Dash ◽  
...  

The pure phase of rutile titanium dioxide or titania (R-TiO2) was prepared by means of a strong acidic sol–gel process followed by treatment using a hydrothermal method. The as-prepared titania nanoparticles existed purely in the rutile phase instead of the mixed anatase phase of the respective titania (R-TiO2). The optimized reaction condition and precursor usage were the critical parameters for the formation of the particle size and uniform crystallinity of the rutile phase of TiO2 nanoparticle fabrication. XRD (X-ray diffraction), and Raman spectroscopic techniques were utilized to confirm the formation of the pure rutile phase of titania. SEM (scanning electron microscope) and TEM (Transmission electron microscope) images showed the cauliflower-like morphology of the as-prepared R-TiO2; reduced particle sizes of below 5 nm were observed and confirmed through high resolution images. The catalytic activity of the as-prepared R-TiO2 was tested under visible light irradiation for methylene blue dye degradation reactions. Dye degradation occurred very effectively, even at higher concentrations of methylene blue (MB), at reduced time intervals from 5 to 3 h of reaction time. The as-prepared rutile phase of pure titania nanoparticles was applied in a catalysis application for the purpose of inducing various types of organic dye degradation or catalytic transformation in the presence of visible light.


2012 ◽  
Vol 584 ◽  
pp. 396-400 ◽  
Author(s):  
Aravind Naga Revuru ◽  
Nagarajan Padmavathy ◽  
Angappan Sheela ◽  
Swamiappan Sasikumar

The major cause of surface and ground water contamination is due to effluent from dyeing industries. The discharged effluent chemicals inhibit light penetration into water bodies and some are considered to be carcinogenic. In this study, the photocatalytic decomposition of the synthetic dye, methylene blue was investigated in the presence of activated TiO2. The TiO2 sample was characterized by using XRD to analyze the presence of anatase and rutile phases. The dye degradation was monitored as a change in absorbance by UV-Visible spectrophotometer. The contributing factors towards dye degradation include both the dye concentration as well as the quantity of TiO2 used. Different quantities of TiO2 in anatase phase was taken and activated under UV radiation for 15 min. and subsequently coated on to TLC plates using 5% polyvinyl alcohol as a binding agent. This photocatalytic plate was kept in the methylene blue dye solution and exposed to sunlight. The results shows that 57% of the 30ppm methylene blue dye gets degraded within 75min., when exposed to UV activated TiO2 in presence of natural sunlight.


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