scholarly journals Comparative study on photocatalytic activity of transition metals (Ag and Ni)-doped ZnO nanomaterials synthesized via sol–gel method

2020 ◽  
Vol 7 (2) ◽  
pp. 191590 ◽  
Author(s):  
A. K. Azfar ◽  
M. F. Kasim ◽  
I. M. Lokman ◽  
H. A. Rafaie ◽  
M. S. Mastuli
Keyword(s):  
Photocatalytic Activity ◽  
Active Sites ◽  
Sol Gel ◽  
Textural Properties ◽  
High Photocatalytic Activity ◽  
Factors Affecting ◽  
Gel Method ◽  
Sol Gel Method ◽  
Zno Nanomaterials ◽  
Almost All

Ag and Ni/ZnO photocatalyst nanostructures were successfully synthesized by a sol–gel method. In this work, the photocatalyst sample was systematically studied based on several factors affecting the performance of photocatalyst, which are size, morphology, band gap, textural properties and the number of active sites presence on the surface of the nanocatalyst. X-ray diffraction revealed that Ag/ZnO nanomaterials experienced multiple phases, meanwhile for Ni/ZnO the phase of nanomaterials were pure and single phase for stoichiometry less than 5%. Field emission scanning electron microscope (FESEM) showed almost all of the synthesized nanomaterials possessed a mixture of nanorods and spherical-like shape morphology. The Ag/ZnO showed high photocatalytic activity, producing at least 14th trials of nanocatalyst reusability on degradation of methyl orange under UV irradiation. Interestingly, this phenomenon was not observed in larger surface area of Ni/ZnO nanomaterials which supposedly favour photocatalytic activity, but instead producing poor photocatalytic performance. The main reasons were studied and exposed by temperature-programmed desorption of carbon dioxide (TPD–CO 2 ) which showed that incorporation of Ag into ZnO lattice has enhanced the number of active sites on the surface of the nanocatalyst. Whereas incorporation of Ni in ZnO has lowered the number of active sites with respect to undoped ZnO. Active sites measurement is effective and significant, providing opportunities in developing an intensive study as an additional factor.

Factors affecting photocatalytic activity of visible light-responsive titanium dioxide doped with chromium ions

2018 ◽  
Vol 8 (18) ◽  
pp. 4726-4733 ◽  
Author(s):  
Naoto Nishiyama ◽  
Keisuke Kozasa ◽  
Toshihiro Okajima ◽  
Mamoru Fujitsuka ◽  
Tetsuro Majima ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Sol Gel ◽  
Factors Affecting ◽  
Gel Method ◽  
Sol Gel Method ◽  
Chromium Ions

Titanium dioxide doped with Cr ions (Cr–TiO2) was synthesized by a sol–gel method, with only water as the solvent, and dialysis.

Fast Sol–Gel Method to Prepare Mesoporous TiO2 with High Photocatalytic Activity

NANO ◽  
2015 ◽  
Vol 10 (01) ◽  
pp. 1550001 ◽  
Author(s):  
Kui Zhang ◽  
Xiangdong Wang ◽  
Xiaoling Guo ◽  
Jie Dai ◽  
Jingyu Xiang
Keyword(s):  
Photocatalytic Activity ◽  
Uv Light ◽  
High Surface ◽  
Sol Gel ◽  
Methyl Orange Solution ◽  
Mesoporous Structure ◽  
High Photocatalytic Activity ◽  
Gel Method ◽  
Sol Gel Method ◽  
Surface Areas

Mesoporous TiO 2 nanoparticles were synthesized via a fast and classical sol–gel method, respectively. Polyacrylamide was used as the template in the fast sol–gel route; the polymerization crosslink by hydrogen bonds between the template and hydrolysates of Ti alkoxides shortens the reaction time from several days to several hours. The X-ray diffraction results testified that only anatase was obtained in the samples, and the crystallite sizes of the samples prepared by fast and classical sol–gel method were 13.6 nm and 20 nm, respectively. Transmission electron microscopy and N 2 adsorption–desorption reveal that the nanocrystals have typical mesoporous structure and high surface areas. The pore sizes and surface areas of the samples prepared by fast and classical sol–gel method are 17.3 nm and 28.2 nm, 154.7 m2/g and 102.6 m2/g, respectively. The photocatalytic degradation of methyl orange solution under UV light irradiation suggests that the mesoporous TiO 2 photocatalyst prepared by the fast sol–gel method exhibits higher photocatalytic activity than the mesoporous TiO 2 prepared via classical sol–gel method.

Green Synthesis of Cobalt Oxide Nanoparticles by a Starch-Assisted Method

2019 ◽  
Vol 9 (3) ◽  
pp. 362-370 ◽  
Author(s):  
D. Vaya ◽  
Meena ◽  
B.K. Das
Keyword(s):  
Photocatalytic Activity ◽  
Cobalt Oxide ◽  
Sol Gel ◽  
Complex Nature ◽  
Oxide Nanoparticles ◽  
Capping Agent ◽  
Chemical Route ◽  
Gel Method ◽  
Sol Gel Method ◽  
Cobalt Oxide Nanoparticles

Background: The properties of the material are altered when material size shifted towards nano-regime. This feature could be used for wastewater treatment process using model pollutant such as dyes. Recently, nanoparticles are synthesized by a green chemical route using different capping agents. This is the reason we adopt starch as green capping agent along with sol-gel method. Objective: To synthesize cobalt oxide nanoparticles by green chemical route and utilized it in degradation of dyes. Methods: Synthesis of cobalt oxide nanoparticles by sol-gel method using starch as a capping agent. The characteristics of surface modifications were investigated by UV-VIS, TEM, SEM, XRD and FTIR techniques. Results: Cobalt oxide nanoparticles synthesized and inhibited photocatalytic activity. Conclusion: Deactivation of photocatalytic activity due to complex nature of starch. This property can be used elsewhere as in light shielding applications to coat and protect surfaces in order to keep them cool and safe from damage as in the painting of vehicles, roofs, buildings, water tanks, etc.

scholarly journals Bismuth Oxide Prepared by Sol-Gel Method: Variation of Physicochemical Characteristics and Photocatalytic Activity Due to Difference in Calcination Temperature

2020 ◽  
Vol 21 (1) ◽  
pp. 108
Author(s):  
Yayuk Astuti ◽  
Brigita Maria Listyani ◽  
Linda Suyati ◽  
Adi Darmawan
Keyword(s):  
Photocatalytic Activity ◽  
Band Gap ◽  
Calcination Temperature ◽  
Bismuth Oxide ◽  
Sol Gel ◽  
Physicochemical Characteristics ◽  
Band Gap Energy ◽  
Gel Method ◽  
Sol Gel Method ◽  
Body Center Cubic

Research on synthesis of bismuth oxide (Bi2O3) using sol-gel method with varying calcination temperatures at 500, 600, and 700 °C has been done. This study aims to determine the effect of calcination temperature on the characteristics of the obtained products which encompasses crystal structure, surface morphology, band-gap energy, and photocatalytic activity for the decolorization of methyl orange dyes through its kinetic study. Bismuth oxide prepared by sol-gel method was undertaken by dissolving Bi(NO3)3·5H2O and citric acid in HNO3. The mixture was stirred then heated at 100 °C. The gel formed was dried in the oven and then calcined at 500, 600, and 700 °C for 5 h. The obtained products were a pale yellow powder, indicating the formation of bismuth oxide. This is confirmed by the existence of Bi–O and Bi–O–Bi functional groups through FTIR analysis. All three products possess the same mixed crystal structures of α-Bi2O3 (monoclinic) and γ-Bi2O3 (body center cubic), but their morphologies and band gap values are different. The higher the calcination temperature, the larger the particle size and the smaller the band gap value. The accumulative differences in characteristics appoint SG700 to have the highest photocatalytic activity compared to SG600 and SG500 as indicated by its percent degradation value and decolorization rate constant.

Structural, Textural and Thermal Characterization of Nano-Mg/Al Hydrotalcite before and after Cr (VI) Removal

2013 ◽  
Vol 755 ◽  
pp. 53-60
Author(s):  
Esthela Ramos Ramírez ◽  
Norma Leticia Gutiérrez Ortega ◽  
Cesar Augusto Contreras Soto ◽  
Gustavo Rangel Porras
Keyword(s):  
Crystalline Structure ◽  
Sol Gel ◽  
Textural Properties ◽  
Kinetic Studies ◽  
Thermal Characterization ◽  
Gel Method ◽  
Sol Gel Method ◽  
Before And After ◽  
Short Time

In this work there was studied the structural, textural and effect that has treat thermal on the removal of Cr (VI) of nanoMg/Al hydrotalcite (NHT) synthesized by the sol-gel method with a ratio of Mg/Al=3. These present the characterization of the nanoMg/Al hydrotalcite before and after Cr (VI) removal, as well as the kinetic studies and of balance. In agreement with the results, when the NHT are thermal treated to 350 °C the hydrotalcite crystalline structure remains but the textural properties are improved and structural. The NHT synthesized by the sol-gel method present a good capacity of removal with values of 91 mg of Cr (VI) removed / g of NHT. The above mentioned capacity of removal gets improved after thermal treating the material, reaching values of removal of 124 mg of Cr (VI) removed / g of NHT. The NHT with the Cr (VI) absorbed show decrease of the crystalline structure, as well as a saturation of the pores that annuls the porosity due to the fact that the Cr (VI) lodges both at the pores and at the intersheets. The time that him takes the HLM to remove the Cr (VI) of the watery solution is alone of 2 minutes, with which it is possible to conclude that the NHT have an excellent aptitude to remove Cr (VI) of watery solutions in an interval of very short time.

scholarly journals Novel N-doped ZrO2 with enhanced visible-light photocatalytic activity for hydrogen production and degradation of organic dyes

RSC Advances ◽  
2018 ◽  
Vol 8 (13) ◽  
pp. 6752-6758 ◽  
Author(s):  
Yuanyang Wang ◽  
Yinghua Zhang ◽  
Haiqiang Lu ◽  
Yanxin Chen ◽  
Zhenmin Liu ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Hydrogen Production ◽  
Visible Light ◽  
Nitrogen Source ◽  
Organic Dyes ◽  
Low Cost ◽  
Sol Gel ◽  
Gel Method ◽  
Sol Gel Method ◽  
Visible Light Photocatalytic

Two new types of N-doped ZrO2 photocatalysts ZON and AZON have been synthesized using ethylenediamine as the nitrogen source by a facile and low-cost sol–gel method.

scholarly journals Visible-enhanced photocatalytic performance of CuWO4/WO3 hetero-structures: incorporation of plasmonic Ag nanostructures

2018 ◽  
Vol 42 (13) ◽  
pp. 11109-11116 ◽  
Author(s):  
R. Salimi ◽  
A. A. Sabbagh Alvani ◽  
N. Naseri ◽  
S. F. Du ◽  
D. Poelman
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Photocatalytic Performance ◽  
Sol Gel ◽  
Light Irradiation ◽  
Photo Degradation ◽  
Gel Method ◽  
Sol Gel Method

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.

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