[Cu-Ag2]O–C3N4 nanoframeworks for efficient photodegradation of wastewaters

2019 ◽  
Vol 44 (2) ◽  
pp. 175-186
Author(s):  
Mohsen Padervand ◽  
Fatemeh Mesri Fasandouz ◽  
Abolghasem Beheshti

CuO- and Ag2O-decorated g-C3N4 photocatalysts were prepared by appropriate chemical modification of carbon nitride nanosheets produced from programmed pyrolysis of urea. After comprehensive characterization by powder X-ray diffraction, diffuse reflectance spectroscopy, Fourier transform–infrared spectroscopy, scanning electron microscopy, and Brunauer–Emmett–Teller analysis methods, their photocatalytic performances were examined for the removal of Acid Blue 92 azo dye, as a typical wastewater component from the textile industry. The X-ray diffraction patterns confirmed the presence of CuO and Ag2O nanoparticles on the surface of the sheets. In addition, diffuse reflectance spectra indicated a considerable reduction of the band gap of pure C3N4 by modification. The photoreaction was discussed mechanistically and the best operational parameters were found to achieve the highest efficiency under visible light.

2018 ◽  
Vol 43 (2) ◽  
pp. 112-120 ◽  
Author(s):  
Mahboubeh Tasviri ◽  
Samin Bargozideh

BiVO4/InVO4 and BiVO4/InVO4/g-C3N4 were prepared by hydrothermal and ultrasonic-assisted hydrothermal methods respectively. All prepared samples were characterised by X-ray diffraction, scanning electron microscopy and UV-Vis diffuse reflectance spectroscopy. The photocatalytic activity of the prepared catalysts was determined by degradation of Acid Blue 92 (AB92) under visible light. The rate constant and efficiency of AB92 degradation over BiVO4/InVO4/g-C3N4 was higher than that over BiVO4/InVO4 which indicates better photocatalytic activity of BiVO4/InVO4/g-C3N4. This enhancement can be attributed to the suitable dispersion of BiVO4 and InVO4 particles on the g-C3N4 surface. Furthermore, the conduction band and valence band edge potentials of InVO4, BiVO4 and g-C3N4 extend the life-time of electron–hole pairs which is beneficial for the improvement of photocatalytic efficiency.


2014 ◽  
Vol 809-810 ◽  
pp. 890-894
Author(s):  
Dan Li ◽  
Lian Wei Shan ◽  
Gui Lin Wang ◽  
Li Min Dong ◽  
Wei Li ◽  
...  

Boron-BiVO4 samples were synthesized by sol-gel method. They were characterized by UV-vis diffuse reflectance spectroscopy, X-ray diffraction. Photocatalytic activity of the obtained BiVO4 samples was investigated through degrading methylene blue (MB). The results reveal that boron-BiVO4 catalysts have monoclinic scheelite structure. The BiVO4 and Co-BiVO4 photocatalysts were responsive to visible light. Co-BiVO4 photocatalyst showed higher photocatalytic activity than pure BiVO4, resulting in the significantly improved efficiency of degradation of MB.


2019 ◽  
Vol 12 (06) ◽  
pp. 1950085 ◽  
Author(s):  
Di Zhao ◽  
Xuezheng An ◽  
Yaxian Sun ◽  
Guihua Li ◽  
Hongyan Liu ◽  
...  

p-n heterojunction Ag2CO3/Ag3PO4/Ni thin films were prepared by electrochemical co-deposition. The surface morphology and structural properties of the thin films were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS). The photocatalytic (PC) properties of the Ag2CO3/Ag3PO4/Ni composite thin films were investigated by their ability to degrade rhodamine B (RhB) and Congo red (CR) under visible light irradiation. The results showed that the photodegradation efficiency of RhB by an Ag2CO3/Ag3PO4/Ni thin film under visible-light irradiation for 30[Formula: see text]min (98.84%) was 2.64 times higher than that of an Ag3PO4/Ni thin film and 3.44 times higher than of an Ag2CO3/Ni thin film. The presence of a [Formula: see text]-[Formula: see text] heterojunction greatly increased the charge conductivity of the film and its ability to photocatalytically reduce dissolved oxygen, which are the main reasons for the improved PC performance of the Ag2CO3/Ag3PO4/Ni films.


2019 ◽  
Vol 9 (8) ◽  
Author(s):  
Mohanna Zarei ◽  
Jamil Bahrami ◽  
Mohammad Zarei

Abstract Zirconia (ZrO2)-modified graphitic carbon nitride (g-C3N4) nanocomposite was used for effective photodegradation of 4-nitrophenol (4-NP) in water. The ZrO2 nanoparticles, g-C3N4 nanosheets, and ZrO2/g-C3N4 nanocomposite were well characterized by including N2 adsorption, X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, UV–Vis diffuse reflectance spectroscopy, photoelectrochemical measurements, and photoluminescence spectroscopy methods. ZrO2/g-C3N4 nanocomposites were formed at room temperature using sonication and used for effective for photodegradation of 4-NP under irradiation with visible light. The nanocomposite samples resulted in a significant increase in photocatalytic activity compared with single-component samples of g-C3N4. In particular, the ZrO2/g-C3N4 nanocomposite exhibited the significant increase in the photocatalytic activity. The ZrO2/g-C3N4 nanocomposite showed an excellent catalytic activity toward the reduction of 4-NP in aqueous medium. Further, ZrO2/g-C3N4 nanocomposite can be reused several times for photocatalytic degradation as well as for 4-NP adsorption.


Clay Minerals ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 491-500 ◽  
Author(s):  
L. Fu ◽  
B. M. Weckhuysen ◽  
A. A. Verberckmoes ◽  
R. A. Schoonheydt

AbstractComplexes of Cu(lysine)2+2 and Cu(histidine)2+2 have been intercalated between the layers of saponite clays by a simple cation exchange procedure from aqueous solutions of preformed Cu(amino acid)2-complexes. Successful immobilization was obtained with an amino acid: Cu2+ ratio of 5, and a pH of 10 and 7.3 for lysine and histidine, respectively. The synthesized materials were investigated as powders and as thin films by electron spin resonance (ESR), diffuse reflectance spectroscopy (DRS) and X-ray diffraction (XRD). The light blue clays are characterized by an axially symmetric ESR spectrum with A//= 192 G, g//= 2.23 and g⊥ = 2.07, and a d-d absorption band around 600 nm, due to the intercalated planar Cu2+-complexes. Ammonia interacts reversibly with these intercalated complexes, suggesting the presence of a free coordination site. The novel synthesized materials are active in various oxidation reactions with t-butyl hydroperoxide as oxidant.


2016 ◽  
Vol 35 (6) ◽  
pp. 559-566 ◽  
Author(s):  
Elaheh Esmaeili ◽  
Mohammad Sabet ◽  
Masoud Salavati-Niasari ◽  
Kamal Saberyan

AbstractPbS nanostructures were synthesized successfully via hydrothermal approach with a new precursor. The products were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and UV–Vis diffuse reflectance spectroscopy (DRS). The effect of different sulfur sources were investigated on product size and morphology.


2014 ◽  
Vol 881-883 ◽  
pp. 1101-1104 ◽  
Author(s):  
Min Jie Zhou ◽  
Peng Cui

In this work, flower-like ZnIn2S4 microspheres were synthesized using a solvothermal method. The as-synthesized samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and ultraviolet-visible diffuse reflectance spectroscopy (DRS) techniques. The photocatalytic activity of the ZnIn2S4 microspheres was investigated. The ZnIn2S4 microspheres exhibit much higher photocatalytic activity than pure P25 TiO2.


2001 ◽  
Vol 16 (1) ◽  
pp. 35-37 ◽  
Author(s):  
Zhigang Zou ◽  
Jinhua Ye ◽  
Hironori Arakawa

Polycrystalline sample of Bi2FeNbO7 was synthesized by the solid-state reaction and characterized by powder x-ray diffraction and Rietveld structure refinement. The optical absorption and structural properties of Bi2FeNbO7 were investigated. It was found that the Bi2FeNbO7 compound has the pyrochlore crystal structure, cubic system with space group Fd3m, and the lattice parameter is a = 10.5233(2) Å. Ultraviolet-visible diffuse reflectance spectroscopy measurement revealed that the band gap of Bi2FeNbO7 is about 2.1(6) eV.


2013 ◽  
Vol 829 ◽  
pp. 912-916 ◽  
Author(s):  
Alireza Khanaki ◽  
Hossein Abdizadeh ◽  
Mohammad Reza Golobostanfard

Nanocrystalline CuInSe2 (CIS) powders were synthesized with a simple open-air solvothermal method as well as under conditions of applying internal imposed pressure. No post-treating processes such as annealing or selenization were used in both methods. The synthesis processes involved the reaction of precursors in an autoclave for different process times. Structural, morphological, and opto-electronic properties of CIS powders were compared. X-ray diffraction patterns (XRD) confirmed the formation of chalcopyrite structure of CIS powders in both approaches at reaction temperature of 220 °C and for short process time. Field emission scanning electron microscopy (FESEM) results show that while CIS powders synthesized under the atmospheric condition are mostly agglomerated, particles have more specific shapes in samples synthesized under internal imposed pressure. Furthermore, the band gap energies of synthesized CIS powders were obtained using diffuse reflectance UV-vis spectroscopy (DRS) measurements.


2016 ◽  
Vol 4 (18) ◽  
pp. 6946-6954 ◽  
Author(s):  
E. N. K. Glover ◽  
S. G. Ellington ◽  
G. Sankar ◽  
R. G. Palgrave

The nature and effects of rhodium and antimony doping in TiO2 have been investigated using X-ray diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Extended X-ray Absorption Fine Structure (EXAFS), X-ray Absorption Near Edge Structure (XANES) and diffuse reflectance spectroscopy.


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