scholarly journals Selective growth of Ti3+/TiO2/CNT and Ti3+/TiO2/C nanocomposite for enhanced visible-light utilization to degrade organic pollutants by lowering TiO2-bandgap

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jeasmin Akter ◽  
Md. Abu Hanif ◽  
Md. Akherul Islam ◽  
Kamal Prasad Sapkota ◽  
Jae Ryang Hahn
Keyword(s):  
Visible Light ◽  
Structural Integrity ◽  
Carbon Layer ◽  
Wide Bandgap ◽  
Blue Dye ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
Excellent Photocatalytic Activity ◽  
Convenient Route ◽  
Walled Carbon Nanotubes

AbstractA convenient route was developed for the selective preparation of two stable nanocomposites, Ti3+/TiO2/CNT (labeled as TTOC-1 and TTOC-3) and Ti3+/TiO2/carbon layer (labeled as TTOC-2), from the same precursor by varying the amount of single-walled carbon nanotubes used in the synthesis. TiO2 is an effective photocatalyst; however, its wide bandgap limits its usefulness to the UV region. As a solution to this problem, our prepared nanocomposites exhibit a small bandgap and wide visible-light (VL) absorption because of the introduction of carbonaceous species and Ti3+ vacancies. The photocatalytic efficiency of the nanocomposites was examined via the degradation of methylene blue dye under VL. Excellent photocatalytic activity of 83%, 98%, and 93% was observed for TTOC-1, TTOC-2, and TTOC-3 nanocomposites within 25 min. In addition, the photocatalytic degradation efficiency of TTOC-2 toward methyl orange, phenol, rhodamine B, and congo red was 28%, 69%, 71%, and 91%, respectively, under similar experimental conditions after 25 min. Higher reusability and structural integrity of the as-synthesized photocatalyst were confirmed within five consecutive runs by photocatalytic test and X-ray diffraction analysis, respectively. The resulting nanocomposites provide new insights into the development of VL-active and stable photocatalysts with high efficiencies.

scholarly journals Selective growth of Ti3+/TiO2/CNT and Ti3+/TiO2/C nanocomposite photocatalysts for enhanced visible-light utilization to degrade organic pollutants by lowering the bandgap of TiO2

2021 ◽  
Author(s):  
Jeasmin Akter ◽  
Md. Abu Hanif ◽  
Md. Akherul Islam ◽  
Kamal Sapkota ◽  
Jae Hahn
Keyword(s):  
Visible Light ◽  
Structural Integrity ◽  
Carbon Layer ◽  
Wide Bandgap ◽  
Blue Dye ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
Excellent Photocatalytic Activity ◽  
Convenient Route ◽  
Walled Carbon Nanotubes

Abstract A convenient route was developed for the selective preparation of two stable nanocomposites, Ti3+/TiO2/CNT (labeled as TTOC-1 and TTOC-3) and Ti3+/TiO2/carbon layer (labeled as TTOC-2), from the same precursor by varying the amount of single-walled carbon nanotubes used in the synthesis. TiO2 is an effective photocatalyst; however, its wide bandgap limits its usefulness to the UV region. As a solution to this problem, our prepared nanocomposites exhibit a small bandgap and wide visible-light (VL) absorption because of the introduction of carbonaceous species and Ti3+ vacancies. The photocatalytic efficiency of the nanocomposites was examined via the degradation of methylene blue dye under VL. Excellent photocatalytic activity of 83%, 98%, and 93% was observed for TTOC-1, TTOC-2, and TTOC-3 nanocomposites within 25 min. In addition, the photocatalytic degradation efficiency of TTOC-2 toward rhodamine B was 71% and for methyl orange (MO) dye was 28% under similar experimental conditions, after 25 min. Higher reusability and structural integrity of the as-synthesized photocatalyst were confirmed within five consecutive runs by photocatalytic test and X-ray diffraction analysis, respectively. The resulting nanocomposites provide new insights into the development of VL-active and stable photocatalysts with high efficiencies.

scholarly journals Effect of Oxalic Acid Leaching on Photocatalytic Activity of Natural Sphalerite

2020 ◽  
Author(s):  
Chukwunonso Onyenanu ◽  
Lovet Emembolu
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Irradiation Time ◽  
Acid Leaching ◽  
Blue Dye ◽  
Light Illumination ◽  
X Ray Diffraction ◽  
X Ray ◽  
Visible Light Illumination

Abstract Photocatalytic activity of the natural semiconducting sphalerite mineral from Abuni, Nasarawa State, Nigeria was studied for the degradation of methylene blue (MB). Natural Sphalerite as a visible – light responsive photocatalyst was characterized by X ray diffraction (XRD), X ray fluorescence (XRF) and surface area analysis. To further enhance the photocatalytic activity of natural Sphalerite, the chemical composition of the sphalerite was varied via leaching with oxalic acids. The photocatalytic activity of the Natural sphalerite, leached sphalerite and as well as the calcined leachates was tested for MB degradation under visible light illumination. The result shows a very high percentage of MB degradation by natural sphalerite after 60mintues of light irradiation time. A composite of ZnO -α –Fe2O3 -ϒ-Fe2O3 with traces amount of MoO and MnO2 was synthesized by calcination of the obtained leachates at 1000°C for 4hours. The photocatalytic degradation of methylene blue dye follows pseudo first order kinetics.

scholarly journals Curd Mediated Facile Synthesis of ZnO/Ag/NiO Heterostructures and Visible Light Assisted Photodegradation of Methylene Blue

2020 ◽  
Vol 32 (12) ◽  
pp. 3203-3208
Author(s):  
J.P. Shubha ◽  
B.S. Prathibha ◽  
N. Jayalakshmi
Keyword(s):  
Electron Microscopy ◽  
Methylene Blue ◽  
Visible Light ◽  
Analytical Techniques ◽  
Zinc Nitrate ◽  
Blue Dye ◽  
Methylene Blue Dye ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Light Concentration

Green fuel perished curd was used to synthesize ZnO/Ag/NiO ternary heterostructure with zinc nitrate, nickel carbonate and silver nitrate as oxidizers. The obtained nanostructure was characterized by various analytical techniques such as powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (FESEM), transmission electron microscopy (TEM). The particles and flakes composition of ZnO/Ag/NiO nanomaterials was confirmed. Photocatalytic activity of ZnO/Ag/NiO was evaluated with methylene blue dye by source of light, concentration of hydrogen ion, catalyst and dye concentrations. The obtained ZnO/Ag/NiO nanoparticles reveal better catalytic property for the photodegradation of methylene blue dye under visible light.

scholarly journals rGO Functionalized ZnO–TiO2 Core-Shell Flower-Like Architectures for Visible Light Photocatalysis

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 332
Author(s):  
Evangelia Vasilaki ◽  
Nikos Katsarakis ◽  
Spyros Dokianakis ◽  
Maria Vamvakaki
Keyword(s):  
Visible Light ◽  
Diffraction Field ◽  
Attenuated Total Reflectance ◽  
Blue Dye ◽  
Core Shell ◽  
X Ray Diffraction ◽  
Absorption Properties ◽  
X Ray ◽  
Visible Light Range ◽  
Reduced Graphene

Core-shell heterostructures with a complex, flower-like morphology, comprising a ZnO core and a TiO2 shell decorated with reduced graphene oxide (rGO) sheets by hydrothermal wrapping, are reported to extend the absorption properties of the semiconductors toward the visible light range. The ternary photocatalysts were characterized by X-ray diffraction, field emission scanning electron microscopy, Raman spectroscopy, diffuse reflectance UV–Vis, and attenuated total reflectance-Fourier transform infrared spectroscopy. Its photocatalytic performance was evaluated under visible light irradiation using methylene blue dye as a model pollutant. The rGO-modified ZnO–TiO2 photocatalyst exhibited superior photoactivity compared to that of the parent ZnO–TiO2 core-shell structures, which was dependent on its graphene content. The enhanced photocatalytic response was attributed to the higher absorption in the visible light range, as well as the pronounced electron and hole separation in the ternary system.

UV-Fenton Discoloration of Methyl Orange Using Fe3O4/MWCNTs as Heterogeneous Catalyst Obtained by an In Situ Strategy

2014 ◽  
Vol 618 ◽  
pp. 208-214 ◽  
Author(s):  
Tian Nuo Shi ◽  
Huan Yan Xu ◽  
Hong Zhou Chang
Keyword(s):  
Methyl Orange ◽  
Synergetic Effect ◽  
X Ray Diffraction ◽  
Solution Ph ◽  
Experimental Conditions ◽  
Fenton Catalyst ◽  
Multi Walled Carbon Nanotubes ◽  
In Suit ◽  
Walled Carbon Nanotubes

As an innovative heterogeneous UV-Fenton catalyst nanocomposite, ferroferric oxide (Fe3O4) with inverse-spinel structure trapped by Multi-walled carbon nanotubes (MWCNTs) was successfully prepared by a facile and in-suit strategy in this study. The as-prepared products were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). An active dye, Methyl Orange (MO) was employed as the target pollutant to evaluate the UV-Fenton efficiency of Fe3O4/MWCNTs nanocomposite. The effects of operating parameters, including solution pH, initial MO concentration, reaction temperature, initial H2O2concentration and catalyst dosage on MO discoloration were detailedly investigated. Control experiments indicated Fe3O4/MWCNTs exhibited higher ability for MO discoloration than bare Fe3O4under the same experimental conditions, which might be attributed to the synergetic effect between Fe3O4and MWCNTs.

Functionalization of Multi-Walled Carbon Nanotubes Using Microwave Method

2021 ◽  
Vol 1039 ◽  
pp. 237-244
Author(s):  
Firas K. Mohamad Alosfur ◽  
Noor J. Ridha ◽  
Mohammad Hafizuddin Haji Jumali ◽  
S. Radiman ◽  
Khawla J. Tahir ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Surface Area ◽  
Structural Integrity ◽  
Area Measurement ◽  
Bet Surface Area ◽  
X Ray Diffraction ◽  
Before And After ◽  
Multi Walled Carbon Nanotubes ◽  
Dispersion Test ◽  
Walled Carbon Nanotubes

Multi-walled carbon nanotubes (MWCNTs) probably hold with each other and agglomerated due to van der Waals force. Functionalized process was used to reduce its ability to agglomerate and to increase dispersion in solution. The present work is focused on the microwave irradiation in order to achieve rapid functionalization of MWCNTs compared with other known techniques. The power of microwave radiation was selected by investigating the structural integrity of the samples by X-ray diffraction (XRD) and Field Emission Scanning Electron Microscopy (FE-SEM), while BET surface area measurement was used to measure the MWCNT surface area before and after treatment. The dispersion test in the solution was performed to determine the separation capability of untreated MWCNTs and f-MWCNTs.

scholarly journals Microwave-Solvothermal Synthesis of Nanostructured BiOBr with Excellent Visible-Light Photocatalytic Properties

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Shuisheng Wu ◽  
Qian Dong ◽  
Jun Wang ◽  
Qingming Jia ◽  
Yanlin Sun ◽  
...  
Keyword(s):  
Visible Light ◽  
Solvothermal Synthesis ◽  
Diffuse Reflectance ◽  
Narrow Band ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microwave Assisted ◽  
Hierarchical Microspheres ◽  
Excellent Photocatalytic Activity ◽  
Visible Light Photocatalytic

Novel BiOBr hierarchical microspheres have been successfully prepared via a facile microwave-assisted solvothermal route and used for visible-light photocatalytic degradation of RhB. The phase and morphology of the products were characterized by powder X-ray diffraction (XRD), thermogravimetric analysis (TG), scanning electron microscopy (SEM), BET, and UV-vis diffuse reflectance spectra. The SEM observations displayed that BiOBr flower-like nanostructure assembled from nanosheets. The BiOBr flower-like nanostructure, with a narrow band gap (2.63 eV), shows excellent photocatalytic activity in the degradation of RhB dye under visible-light, much higher than those of BiOBr nanosheet and P25 photocatalysts.

Photocatalytic H2 production on trititanate nanotubes coupled with CdS and platinum nanoparticles under visible light: revisiting H2 production and material durability

2017 ◽  
Vol 198 ◽  
pp. 419-431 ◽  
Author(s):  
Hyunwoong Park ◽  
Hsin-Hung Ou ◽  
Minju Kim ◽  
Unseock Kang ◽  
Dong Suk Han ◽  
...  
Keyword(s):  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
H2 Production ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
Thermal Synthesis ◽  
X Ray ◽  
Transmission Electron ◽  
Detailed Surface ◽  
Efficient Charge

The photocatalytic production of molecular hydrogen (H2) on ternary composites of Pt, CdS, and sodium trititanate nanotubes (NaxH2−xTi3O7, TNTs) is examined in an aqueous 2-propanol (IPA) solution (typically 5 vol%) at a circum-neutral pH under visible light (λ > 420 nm). The H2 production rates are dependent on the Pt-loading level, and the optimum production rate in the Pt/CdS/TNTs is approximately six times higher than that in Pt/CdS/TiO2. A D2O solution containing 5 vol% IPA leads only to the production of D2 molecules, whereas increasing the IPA amount to 30 vol% leads to the production of DH molecules. This indicates that the Pt/CdS/TNTs composites enable H2 production via true water splitting under our typical experimental conditions. X-ray photoelectron spectroscopy (XPS) analyses of the as-synthesized Pt/CdS/TNTs and those used for 6 and 12 h show that metallic Pt on the CdS/TNTs is less susceptible to oxidation than Pt on CdS/TiO2. In addition, photocorrosion of CdS (i.e., sulfate formation) is significantly inhibited during the photocatalytic H2 production reactions in the Pt/CdS/TNTs because of the efficient charge transfer via the TNTs framework. The Pt/CdS/TNTs samples are thermally more stable than Pt/CdS/TiO2 and CdS/TNTs, effectively inhibiting the formation of CdO during the thermal synthesis. Detailed surface characterizations of the as-synthesized ternary composites are performed using X-ray diffraction, transmission electron microscopy, energy dispersive spectroscopy, and XPS.

Visible-Light Driven Effective Photocatalytic Degradation of Methylene Blue Dye Using Perforated Curly Zn0.1Ni0.9O Nanosheets

2020 ◽  
Vol 20 (9) ◽  
pp. 5759-5764
Author(s):  
V. Karthikeyan ◽  
G. Gnanamoorthy ◽  
P. Varun Prasath ◽  
V. Narayanan ◽  
Suresh Sagadevan ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Visible Light ◽  
Photocatalytic Degradation ◽  
Organic Waste ◽  
Hydrothermal Process ◽  
Blue Dye ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Visible Light Driven

Herein, we report the facile synthesis, characterization and visible-light-driven photocatalytic degradation of perforated curly Zn0.1Ni0.9O nanosheets synthesized by hydrothermal process. The X-ray diffraction (XRD) and scanning electron microscopy (SEM) studies confirmed the cubic phase crystalline structure and growth of high density perforated curly Zn0.1Ni0.9O nanosheets, respectively. As a photocatalyst, using methylene blue (MB) as model pollutant, the synthesized nanosheets demonstrated a high degradation efficiency of ~76% in 60 min under visible light irradiation. The observed results suggest that the synthesized Zn0.1Ni0.9O nanosheets are attractive photocatalysts for the degradation of toxic organic waste in the water under visible light.

scholarly journals Composite Magnetic Photocatalyst Bi5O7I/MnxZn1−xFe2O4: Hydrothermal-Roasting Preparation and Excellent Photocatalytic Activity

Nanomaterials ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 118 ◽  
Author(s):  
Hailong Wang ◽  
Longjun Xu ◽  
Chenglun Liu ◽  
Yuan Lu ◽  
Qi Feng ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Energy Gap ◽  
X Ray Diffraction ◽  
Orthorhombic Crystal ◽  
Magnetic Photocatalyst ◽  
Transmission Electron ◽  
Excellent Photocatalytic Activity ◽  
Average Recovery Rate

A new composite magnetic photocatalyst, Bi5O7I/MnxZn1−xFe2O4, prepared by a hydrothermal-roasting method was studied. The photocatalytic properties of Bi5O7I/MnxZn1−xFe2O4 were evaluated by degradation of Rhodamine B (RhB) under simulated sunlight irradiation, and the structures and properties were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet-visible light (UV-Vis) diffuse reflectance spectra (DRS), and a vibrating sample magnetometer (VSM). The results indicated that Bi5O7I/MnxZn1−xFe2O4 was an orthorhombic crystal, which was similar to that observed for Bi5O7I. Bi5O7I/MnxZn1−xFe2O4 consisted of irregularly shaped nanosheets that were 40–60 nm thick. The most probable pore size was 24.1 nm and the specific surface area was 7.07 m2/g. Bi5O7I/MnxZn1−xFe2O4 could absorb both ultraviolet and visible light, and the energy gap value was 3.22 eV. The saturation magnetization, coercivity and residual magnetization of Bi5O7I/MnxZn1−xFe2O4 were 3.9 emu/g, 126.6 Oe, and 0.7 emu/g respectively, which could help Bi5O7I/MnxZn1−xFe2O4 be separated and recycled from wastewater under the action of an external magnetic field. The recycling experiments revealed that the average recovery rate of the photocatalyst was 90.1%, and the photocatalytic activity was still more than 81.1% after five cycles.

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