Suitability of Iron (Fe)-Doped Tungsten Oxide (WO3) Nanomaterials for Photocatalytic and Antibacterial Applications

Author(s):  
G. Thirumoorthi ◽  
B. Gnanavel ◽  
M. Kalaivani ◽  
Abirami Ragunathan ◽  
Hariharan Venkatesan

Pure and “Fe ([Formula: see text][Formula: see text]wt.%)-doped” WO[Formula: see text] nanoparticles were prepared by facile microwave irradiation method and that was investigated for strong photo catalytic and antibacterial activity applications for the first time. The primary aim of this work is to reveal the great importance of oxygen vacancies ([Formula: see text] due to dopant (Fe[Formula: see text] for photo catalytic and antibacterial activity applications. This work also discusses the contribution of oxygen vacancies and their dependence on surface area and phase formation which are of great research interest for water purification and biological sciences. Herein, pure and “Fe ([Formula: see text][Formula: see text]wt.%)-doped” WO[Formula: see text] nanoparticles were successfully synthesized by facile microwave irradiation (MWI) method (2.45 GHz/240W/10min) in ambient atmosphere. The phase formation and the crystalline nature of the prepared products were evaluated using powder X-ray diffraction (XRD). It confirmed the phase formation of orthorhombic and monoclinic phase formations for the pure (WO[Formula: see text]H2O) and annealed samples (W[Formula: see text]O[Formula: see text] and WO[Formula: see text], respectively. Optical behavior of the samples from UV-Vis diffuse reflectance analysis revealed that W[Formula: see text]O[Formula: see text] has remarkable bandgap values (1.96[Formula: see text]eV) that clearly emphasizes the transfer of oxygen ions which helps in the movement of oxygen vacancies inside the crystalline domain. The morphological nature of the prepared products was observed by FE-SEM analysis and the average dimension was found to be 0.2–3.2[Formula: see text][Formula: see text]m and 2–4[Formula: see text][Formula: see text]m for the pure and annealed products, respectively. The specific surface area from BET analysis explored that W[Formula: see text]O[Formula: see text] having 55.16[Formula: see text]m2g[Formula: see text] was found to be higher than that of commercially available WO3. The photocatalytic behavior of the prepared compounds morphologies was investigated via Rhodamine B (RhB) degradation under visible light irradiation. These results showed “Fe-doped” annealed WO3 nanoparticles have degradation efficiency of 86.9% along with high stable nature. On the other hand, to identify the suitability of the prepared products for antibacterial activity, the microbial strains of Gram-positive Bacillus sp. and Gram-negative strains of Pseudomonas sp. and Salmonella sp. were used for the antimicrobial assay[Formula: see text] The results indicated that W[Formula: see text]O[Formula: see text] showed enhanced antibacterial nature when compared to that of Stoichiometry tungsten oxide (WO[Formula: see text] nanomaterials. From these observations, this work emphasizes the importance of oxygen vacancies for antibacterial activity applications.

2021 ◽  
Vol 36 (1) ◽  
pp. 9-15
Author(s):  
I.N Gana ◽  
V.U Ohageria ◽  
U.G Akpan ◽  
I.J Ani

The use of chemicals for the synthesis of photocatalyts poses threat to the environment. In this study, an active photocatalyst, Dalbejiya Dongoyaro (Azadirachta indica)-based zinc oxide (ZnO) was biosynthesized from zinc acetate dihydrate using sol gel and precipitation methods. The synthesized samples were characterized using Fourier Transfer InfraRed (FTIR), X-Ray Diffractometry (XRD), Brunauer Emmet Teller (BET), Energy Dispersive X-ray Spectroscopy (EDS) and Scanning Electron Microscopy (SEM) characterization techniques. The XRD and SEM analysis of the green synthesized and non-green synthesized ZnO demonstrated the formation of hexagonal wurtzite crystalline structure and agglomerated morphology. EDX analysis demonstrated the existence of Zn and O as the major constituents of the as-synthesized nanoparticles with traces of carbon which could be attributed to the carbon tape of the sample holder. The BET analysis displayed that the surface area of the ZnO nanoparticles increased from 23.75 to 97.08 cm3/g after the green synthesis. Based on the surface area values, it can be derived that neem leaf extract enhanced the surface area of the green synthesized sample. Green synthesis is a promising route for the synthesis of photocatalyst nanoparticle which is environmentally friendly and sustainable method. Keywords: Zinc oxide, Neem leaf extract, Photocatalyt, Degradation, Bio-synthesis


Clay Minerals ◽  
2012 ◽  
Vol 47 (2) ◽  
pp. 231-242 ◽  
Author(s):  
S. Ramesh ◽  
Y. S. Bhat ◽  
B. S. Jai Prakash

AbstractWe report a montmorillonite material with enhanced surface area but with very little alteration in cation exchange capacity (CEC) upon dealumination with para toluene sulphonic acid (p-TSA). The new material shows higher catalytic activity in comparison with mineral-acid-treated clay. Montmorillonite clay was treated with p-TSA for 10 minutes under microwave irradiation. The resulting clay was characterized by CEC, X-ray diffraction (XRD), BET analysis, Fourier transform infrared spectroscopy (FT-IR), temperature programmed desorption (TPD) of ammonia and cyclic voltametry (CV) techniques. XRD patterns show an unchanged structure of pristine matrix after the acid action. BET analysis revealed an increase in the surface area and pore volume on p-TSA treatment, indicating formation of voids in the octahedral layer which suggests dealumination. Nitrogen adsorption-desorption curves showed the creation of new micro porous regions, possibly in the octahedral sheets. In contrast to mineral acid treatment, p-TSA treated clay samples showed similar CEC which shows the absence of dissolution of isomorphously substituted Mg and Fe ions present in the octahedral layer. CV studies confirm the formation of an Al-p-TSA complex, suggesting dissolution of aluminium octahedral sheets. The complex subsequently hydrolyses, replacing interlayer cations with Al3+ ions. Similar treatment with mineral acid resulted in clay with enhanced surface area but with reduced CEC, evidently due to the removal of isomorphously substituted Fe and Mg. Further, the p-TSA treated clays showed relatively higher esterification activity under solvent-free microwave irradiation. The p-TSA treated clay retained its activity even after three subsequent runs and thus can be exploited for practical applications.


2020 ◽  
Vol 27 (1) ◽  
pp. 424-432
Author(s):  
Hongkai Zhao ◽  
Kehan Zhang ◽  
Shoupeng Rui ◽  
Peipei Zhao

AbstractIn the present contribution, an environmental-friendly and cost-effective adsorbent was reported for soil treatment and desertification control. A novel foam gel material was synthesized here by the physical foaming in the absence of catalyst. By adopting modified microcrystalline cellulose and chitosan as raw materials and sodium dodecyl sulfonate (SDS) as foaming agent, a microcrystalline cellulose/chitosan blend foam gel was synthesized. It is expected to replace polymers derived from petroleum for agricultural applications. In addition, a systematical study was conducted on the adsorbability, water holding capacity and re-expansion performance of foam gel in deionized water and brine under different SDS concentrations (2%–5%) as well as adsorption time. To be specific, the adsorption capacity of foam gel was up to 105g/g in distilled water and 54g/g in brine, indicating a high water absorption performance. As revealed from the results of Fourier transform infrared spectroscopy (FTIR) analysis, both the amino group of chitosan and the aldehyde group modified by cellulose were involved. According to the results of Scanning electron microscope (SEM) analysis, the foam gel was found to exhibit an interconnected pore network with uniform pore space. As suggested by Bet analysis, the macroporous structure was formed in the sample, and the pore size ranged from 0 to 170nm. The mentioned findings demonstrated that the foam gel material of this study refers to a potential environmental absorbent to improve soil and desert environments. It can act as a powerful alternative to conventional petroleum derived polymers.


2010 ◽  
Vol 177 ◽  
pp. 447-450 ◽  
Author(s):  
Xin Zhang ◽  
Yi Wen Hu ◽  
Yin Wu ◽  
Wen Jie Si

The purpose of this study was to evaluate the crystal phase formation behavior and its influence on the mechanical properties of LiO2-SiO2-P2O5 glass-ceramics system. High temperature XRD was used to analyze the crystal phase formation in situ. The crystalline phases in the material both before and after heat-treatment were also analyzed. The flexural strength was measured by three-point bending test according to ISO 6872:2008(E). The SEM analysis showed that the high strength of the glass-ceramics is attributed to the continuous interlocking microstructure with fine lithium disilicate crystallines.


2011 ◽  
Vol 117-119 ◽  
pp. 786-789 ◽  
Author(s):  
Wen Churng Lin ◽  
Wein Duo Yang ◽  
Zen Ja Chung ◽  
Hui Ju Chueng

Titanate nanotubes were synthesized at various hydrothermal temperatures and reaction times by the hydrothermal process and used as photocatalyst. BET analysis was conducted in order to find out the surface area of these as-prepared samples and it was found that the surface area increases with rise in temperature till 130 oC. Synthesized as-prepared titanate nanotubes were applied on methylene blue degradation from aqueous media by UV irradiation. It was observed that dye removes ~99% from the aqueous media at a titanate nanotubes dose of 2 g/L.


2017 ◽  
Vol 4 (11) ◽  
pp. 1783-1790 ◽  
Author(s):  
Kai-Li Yan ◽  
Jing-Qi Chi ◽  
Zi-Zhang Liu ◽  
Bin Dong ◽  
Shan-Shan Lu ◽  
...  

Ag-doped mesoporous NiCoO nanorods as efficient and stable electrocatalysts for oxygen evolution reaction have been synthesized with desirable conductivity, high surface area and rich oxygen vacancies.


2021 ◽  
Author(s):  
Prakash Parajuli ◽  
Sanjit Acharya ◽  
Julia Shamshina ◽  
Noureddine Abidi

Abstract In this study, alkali and alkaline earth metal chlorides with different cationic radii (LiCl, NaCl, and KCl, MgCl2, and CaCl2) were used to gain insight into the behavior of cellulose solutions in the presence of salts. The specific focus of the study was evaluation of the effect of salts’ addition on the sol-gel transition of the cellulose solutions and on their ability to form monoliths, as well as evaluation of the morphology (e.g., specific surface area, pore characteristics, and microstructure) of aerocelluloses prepared from these solutions. The effect of the salt addition on the sol-gel transition of cellulose solutions was studied using rheology, and morphology of resultant aerogels was evaluated by Scanning Electron Microscopy (SEM) and Brunauer-Emmett-Teller (BET) analysis, while the salt influence on the aerocelluloses’ crystalline structure and thermal stability was evaluated using powder X-Ray Diffraction (pXRD) and Thermogravimetric Analysis (TGA), respectively. The study revealed that the effect of salts’ addition was dependent on the component ions and their concentration. The addition of salts in the amount below certain concentration limit significantly improved the ability of the cellulose solutions to form monoliths and reduced the sol-gel transition time. Salts of lower cationic radii had a greater effect on gelation. However, excessive amount of salts resulted in the formation of fragile monoliths or no formation of gels at all. Analysis of surface morphology demonstrated that the addition of salts resulted in a significant increase in porosity and specific surface area, with salts of lower cationic radii leading to aerogels with much larger (~1.5 and 1.6-fold for LiCl and MgCl2, respectively) specific surface area compared to aerocelluloses prepared with no added salt. Thus, by adding the appropriate salt into the cellulose solution prior to gelation, the properties of aerocelluloses that control material’s performance (specific surface area, density, and porosity) could be tailored for a specific application.


Author(s):  
Andaru Dena Prasiwi ◽  
Wega Trisunaryanti ◽  
Triyono Triyono ◽  
Iip Izul Falah ◽  
Darma Santi ◽  
...  

Synthesis of mesoporous carbon from Merbau wood (Intsia spp.) waste by microwave method as nickel catalyst support for α-cellulose hydrocracking had been carried out. The Merbau wood sawdust was carbonized at 800 °C to produce C800 and the C800 was treated by microwave irradiation (399 W) for 5 min to produce C800MW. The Merbau wood flakes, which were only treated by microwave irradiation (399 Watts) for 30 min produced CMW. Wet impregnation technique was carried out to disperse the Ni metal (1.0, 1.5, and 2.0 wt.%) onto the best mesoporous carbon. The mesoporous carbons were analyzed by Fourier Transform Infra-Red Spectroscopy (FTIR), Surface Area Analyzer (SAA) and Scanning Electron Microscopy (SEM). The hydrocracking of pyrolyzed α-cellulose was carried out at 400 °C. The liquid product was analyzed by Gas Chromatograph-Mass Spectrometer (GC-MS). The results showed that the C800MW was the best performance carbon and it had a specific surface area, total pore volume, average pore diameter and acidity of 364.12 m2/g, 0.28 cm3/g, 3.03 nm, and 2.18 mmol/g, respectively. The Ni1.5/C800MW catalyst produced the highest conversion of liquid product (58.76 wt.%) than the Ni1/C800MW (57.51 wt.%) and Ni2/C800MW (34.18 wt.%).


Author(s):  
Selma M.H. AL-Jawad ◽  
Zahraa S. Shakir ◽  
Duha S. Ahmed

ZnO/MWCNTs hybrid and doped with different concentration of Nickel element prepared by using Sol-gel been technique reported. All samples were prepared and characterized by X-Ray Diffraction Analysis (XRD), Energy Dispersive X-ray Spectroscopy (EDS), Fourier-Transform Infrared Spectroscopy (FTIR), Field-Emission Scanning Electron Microscopy (FE-SEM), and UV-Vis spectroscopy have been identified the structural, optical and morphological properties. X-ray diffraction showed the polycrystalline nature with hexagonal wutzite structure of hybrid and doped with Nickel. The crystalline size of the hybrid nanostructure was increasing from 23.73 nm to 34.59 nm. Besides, the UV-Vis spectroscopy showed a significant decrease in the band gap values from 2.97 eV to 2.01 eV. Whereas the FE-SEM analysis confirm the formation spherical shapes of ZnO NPs deposited on cylindrical tubes representing the MWCNTs. The antibacterial activity reveals that the inhibition zone of Ni doped-ZnO/MWCNTs hybrid was 28.5 mm, 26.5 mm toward E. coli and S. aureus bacteria, respectively.


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