Visible-light photocatalytic activity of Fe@TiO2 core–shell composite synthesized by sol–gel method

2020 ◽  
Vol 34 (22n24) ◽  
pp. 2040127
Author(s):  
Min Yen Yeh ◽  
Tzu Yuan Yang ◽  
Tsung Chi Wu ◽  
Shiow Yueh Lee ◽  
Shun Hsyung Chang

Core–shell structure [Formula: see text] was synthesized by sol–gel method. The photocatalytic degradation of methylene blue over the [Formula: see text] reached 98% under UV light irradiation within 5 h. The band gap of the core–shell [Formula: see text] was found to have a redshift through a sintering treatment. The redshifted [Formula: see text] had a good performance of methylene-blue degradation (reaching 85%) under visible light irradiation for 5 h.

2018 ◽  
Vol 42 (13) ◽  
pp. 11109-11116 ◽  
Author(s):  
R. Salimi ◽  
A. A. Sabbagh Alvani ◽  
N. Naseri ◽  
S. F. Du ◽  
D. Poelman

A new plasmonic Ag hybridized CuWO4/WO3 heterostructured nanocomposite was successfully synthesized via a ligand-assisted sol gel method and the photocatalytic activity was evaluated by photo-degradation of methylene blue (MB) under visible light irradiation.


2018 ◽  
Vol 5 (2) ◽  
pp. 120-126 ◽  
Author(s):  
Abdurrashid Haruna ◽  
Ibrahim Abdulkadir ◽  
Suleiman Ola Idris

Perovskite-like BiFeO3 nanoparticles doped with barium and sodium ions were synthesized via the citric acid route by the sol-gel method. The as-prepared Bi0.65Na0.2Ba0.15FeO3 nanopowders were divided into three equal portions and separately annealed at various annealing temperatures of 600, 700 and 800°C. The powders were characterized using X-ray diffraction (XRD) and crystallized with a rhombohedral R3c space group. Scanning electron microscopy was used to determine the morphology of the crystal and Fourier transform infrared spectroscopy was conducted at room temperature to determine the phase purity and the B-site formation in the perovskite structure. The UV-vis diffuse reflectance spectroscopy of all the materials was investigated, showing strong photoabsorption (λ > 420 nm). The doping effect of BiFeO3 enhanced photocatalytic activity while it significantly reduced the energy bandgap to 2.05 eV (for BNBFO at 800°C) which showed strong visible light absorption. The photocatalytic activity of Bi0.65Na0.2Ba0.15FeO3 nanomaterials was tested by monitoring the degradation rate of methylene blue dye pollutant under visible light irradiation in aqueous solution. All powders showed photoactivity after 2 hours of visible light irradiation. The annealing temperature greatly affected the methylene blue degradation, showing the efficiencies of 57, 67 and 75 % for BNBFO at 600, 700 and 800°C, respectively. Kinetic studies were carried out and the rate constants of 6.70 x 10-3, 8.90 x 10-3 and 1.05 x 10-2 min-1 were obtained for powders annealed at 600, 700 and 800°C, respectively. The photocatalytic mechanism of the degradation process was proposed in this study.


2016 ◽  
Vol 45 (6) ◽  
pp. 408-418 ◽  
Author(s):  
Swee-Yong Pung ◽  
Yim-Leng Chan ◽  
Srimala Sreekantan ◽  
Fei-Yee Yeoh

Purpose The purpose of this study is to synthesize a semiconductor photocatalyst which responds to both UV light and visible light in removal of organic dyes. Design/methodology/approach ZnO nanoparticles were pre-synthesised via sol-gel method using zinc nitrate tetrahydrate and methanamine at 90°C for 20 h. Subsequently, the as-synthesised ZnO nanoparticles were filtered, washed and dried. To synthesize ZnO-MnO2 core shell nanocomposites (CSNs), 2:3 M ratio of KMnO4 and MnSO4 solution was stirred for an hour. Next, ZnO nanoparticles were added into the solution. The solution was heated at 160°C for 3 h for the formation of ZnO-MnO2 CSNs. The structural, optical and photocatalytic properties of ZnO-MnO2 CSNs were characterised by field emission scanning electron microscope, transmission electron microscopy (TEM), X-ray diffractometer and PL spectroscopy, respectively. Findings The photodegradation efficiencies of rhodamine B (RhB) dye by ZnO-MnO2 CSNs as photocatalysts are 87.1 per cent under UV irradiation and 76.6 per cent under visible light irradiation, respectively. Their corresponding rate constants are 0.016 min−1 under UV irradiation and 0.013 min−1 under visible light irradiation. It can be concluded that N-deethylation was the dominant step during the photodegradation of RhB dye as compared to cycloreversion. The ZnO-MnO2 CSNs demonstrated good photostability after three consecutive runs. Originality/value ZnO-MnO2 CSN photocatalyst which could response to UV and visible light in degradation of RhB dye was synthesised using sol-gel method. The analysis shows that N-deethylation was the key photodegradation mechanism of RhB by ZnO-MnO2 CSN.


2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Suh Cem Pang ◽  
Sze Yun Kho ◽  
Suk Fun Chin

Fe3O4/SiO2/TiO2core-shell nanoparticles were synthesized via a sol-gel method with the aid of sonication. Fe3O4nanoparticles were being encapsulated within discrete silica nanospheres, and a layer of TiO2shell was then coated directly onto each silica nanosphere. As-synthesized Fe3O4/SiO2/TiO2core-shell nanoparticles showed enhanced photocatalytic properties as evidenced by the enhanced photodegradation of methylene blue under UV light irradiation.


Author(s):  
M.Rahim Uddin ◽  
Maksudur R. Khan ◽  
M. Wasikur Rahman ◽  
Chin Kui Cheng ◽  
Abu Yousuf

The present work is a significant approach to explore the photo-conversion of carbon dioxide (CO2) into methanol on Bi2S3/Cds photocatalyst under visible light irradiation. In this perspective, Bi2S3 nanoparticles have been successfully synthesized via corresponding salt and thiourea assisted sol-gel method. An innovative hetero-system Bi2S3/CdS has been proposed to achieve methanol photo evolution and its photocatalytic activities have been investigated.


2013 ◽  
Vol 320 ◽  
pp. 220-225 ◽  
Author(s):  
Xiao Ye Fu ◽  
Xiu Hong Liang

In this paper, we prepared a series of powders (pure TiO2 and Ce-doped TiO2) by sol-gel method and characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), infrared spectrometer (IR) and UV spectrophotometer. The results indicated that the doped Ce influence the crystal structure of TiO2 and improve the temperature of crystal transformation. In the degradation of MB experiment, after 5 hours, the degradation efficiency of them (pure TiO2 , Ce-doped TiO2 and P25) under UV light is about 99.1%, while under visible light,Ce-doped TiO2 is about 60% higher than pure TiO2 and P25, up to 73%. This illustrates that the doped Ce increase the absorption to visible light and improve the photocatalytic efficiency.Key Words: TiO2, Ce-doped TiO2, photocatalyst, sol-gel method, crystal form


2021 ◽  
Vol 9 (4) ◽  
pp. 105557
Author(s):  
Fahim Amini Tapouk ◽  
Seperhr Padervand ◽  
Kamyar Yaghmaeian ◽  
Mirzaman Zamanzadeh ◽  
Somayeh Yousefi ◽  
...  

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