Preparation and study of Z-type heterojunction composite photocatalytic material with Ag2MoO4 modified rosette-like Bi2WO6 with Ag-SPR promoting effect

Author(s):  
Yufen Gu ◽  
Guo Bobo

Abstract Here, the novel Ag 2 MoO 4 /Bi 2 WO 6 ( AMO/BWO ) heterojunction composite photocatalysts were synthesized by a two-step method (co-precipitation method + hydrothermal method) and characterized by a variety of characterization techniques including XRD, XPS, SEM, TEM, UV-vis DR spectroscopy, PL spectroscopy and FTIR spectroscopy, as well as EIS analyses, and photocurrent response for confirming the formation of Z-type heterojunctions. The generation and transfer of electron/holes in the AMO/BWO heterojunctions excited by simulated sunlight were analyzed. Under simulated sunlight, the photocatalytic performance of AMO/BWO composites were studied by degradation of organic pollutants. The experimental results show that the 30wt%AMO@BWO is the best photocatalytic composite material among all samples. Due to the prolonging of lifetime of the photoexcited electrons in the CB of AMO and holes in the VB of BWO, these carriers are more effective to participate in photodegradation reactions. An electron/hole transfer mechanism of the Z-scheme heterojunctions is proposed to illustrate the enhanced photodegradation performance of the AMO/BWO composite samples.

2017 ◽  
Vol 264 ◽  
pp. 74-78
Author(s):  
Ismaila Abdullahi ◽  
I. Zainol

The synthesis of a novelzinc doped chitosan-hydroxyapatite (chitosan-HAp) composite was done viain situ co-precipitation method. FTIR results showed that zinc is incorporated into the composite formed and is less crystalline compared to the pure hydroxyapatite (HAp). XRD results obtained showed that the incorporation of zinc into the lattice of the chitosan-HAp led to changes in the crystallinity, crystallite size and lattice constant of the composite material. FESEM images of the samples revealed that the novel material has a morphological features that resemble that of bone mineral.


2021 ◽  
Vol 317 ◽  
pp. 217-226
Author(s):  
Ismaila Abdullahi ◽  
Ismail Zainol

Chitosan-hydroxyapatite composite doped with strontium was synthesised via in situ co-precipitation method. Physicochemical properties of the composite obtained were analysed using X-ray diffraction (XRD), infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDX) and Thermogravimetry with differential thermal analysis (DT-TGA). The synthesized composite was subjected to bioactivity studies in simulated body fluid (SBF). The calcium release from the sample in SBF was measured using atomic absorption spectroscopy (AAS). The physicochemical properties and bioactivity of the novel composite was compared with that of hydroxyapatite, strontium doped hydroxyapatite and chitosan hydroxyapatite. The in vitro bioactivity studies of the novel composite showed that it has a higher release of Ca2+ in the SBF compared to the other samples. The novel material was also found to induce more Ca2+ deposition after 28 days of immersion in the SBF. Hence, the novel composite material has the potential to be used as biomaterials for clinical application.


2021 ◽  
Vol 33 (10) ◽  
pp. 2293-2300
Author(s):  
S. Nikhil ◽  
R. Arunadevi ◽  
Krishna Veni ◽  
C. Sudhakar ◽  
A. Karthika ◽  
...  

The removal of tartrazine dye from aqueous solution using g-C3N4/Fe3O4 nanocomposites was studied. The g-C3N4/Fe3O4 nanocomposites were synthesized using simple co-precipitation method. The synthesized nanocomposites were characterized by spectral (UV-Vis DRS, FT-IR) and analytical (PXRD, SEM, EDAX, HRTEM) techniques. Photodegradation of tartrazine dye using the synthesized catalyst was studied. The g-C3N4/Fe3O4 nanocomposites exhibited excellent photocatalytic performance by degrading tartrazine (90%) at 0.1 g/L of catalyst and 20 μM initial dye concentration at pH 3. The excellent performance by the catalyst was attributed to the highest electron hole pair generation. The kinetic study revealed that the photodegradation of tartrazine obeyed pseudo first-order kinetics.


2021 ◽  
Author(s):  
Hao Wu ◽  
Fanming Meng ◽  
Xingbing Liu ◽  
Bo Yu

Abstract In this paper, Z-scheme Bi2MoO6/CNTs/g-C3N4 composite-photocatalysts were prepared through a simple hydrothermal method. The analysis was performed by XRD, FT-IR, SEM, EDS, TEM, HRTEM, XPS, BET, UV-Vis diffuse reflectance and PL spectrums. Various analyses show that CNTs not only act as excellent charge transfer bridges, but also enable the formation of a Z-scheme of charge transfer mechanism between Bi2MoO6 and g-C3N4. This process not only effectively isolates electrons and holes, but also prolongs electron-hole pair lifetimes, resulting in a substantial improvement in the photocatalytic performance of the composite photocatalyst. Best photocatalytic degradation performance was shown by Bi2MoO6/CNTs/g-C3N4 composite photocatalyst under simulated sunlight, while the composite photocatalyst still maintained extremely high degradation performance in cycling tests.


2011 ◽  
Vol 393-395 ◽  
pp. 894-897
Author(s):  
Ya Dong ◽  
Hui Wen Yuan ◽  
Ya Ru Ni ◽  
Chun Hua Lu ◽  
Zhong Zi Xu

The novel kind flowerlike mesoporous spheres of calcium silicate hydrate (CaO•SiO2•H2O, CSH) have been synthesized by co-precipitation method on based with water/alcohol/calvital/ tetraethyl orthosilicate (TEOS) system. The synthesized CSH were applied as a carrier to study the loaded behaviors of ibuprofen(IBU),was used to investigate the drug loading behavior of the CSH for different times has been also discussed. The drug loading capacities(DLCs) of CSH loaded for 12h has reached 116.78wt.%. The structural, morphological and textural properties were investigated by SEM, FTIR, TG and BET. The results show that it would be a good candidate as drug carrier for bone repair.


2015 ◽  
Vol 7 (2) ◽  
pp. 1393-1403
Author(s):  
Dr R.P VIJAYALAKSHMI ◽  
N. Manjula ◽  
S. Ramu ◽  
Amaranatha Reddy

Single crystalline nano-sized multiferroic BiFeO3 (BFO) powders were synthesized through simple chemical co-precipitation method using polyethylene glycol (PEG) as capping agent. We obtained pure phase BiFeO3 powder by controlling pHand calcination temperature. From X-ray diffraction studies the nanoparticles were unambiguously identified to have a rhombohedrally distorted perovskite structure belonging to the space group of R3c. No secondary phases were detected. It indicates single phase structure. EDX spectra indicated the appearance of three elements Bi, Fe, O in 1:1:3. From the UV-Vis diffuse reflectance spectrum, the absorption cut-off wavelength of the BFO sample is around 558nm corresponding to the energy band gap of 2.2 eV. The size (60-70 nm) and morphology of the nanoparticles have been analyzed using transmission electron microscopy (TEM).   Linear M−H behaviour and slight hysteresis at lower magnetic field is observed for BiFeO3 nanoparticles from Vibrating sample magnetometer studies. It indicates weak ferromagnetic behaviour at room temperature. From dielectric studies, the conductivity value is calculated from the relation s = L/RbA Sm-1 and it is around 7.2 x 10-9 S/m.


2020 ◽  
Vol 3 (1) ◽  
pp. 30-33
Author(s):  
Muthulakshmi M ◽  
Madhumitha G

Nanotechnology is a field of applied science focused on design, synthesis and characterization of nanomaterials. The nickel and magnesium have improved their applications in transparent electrodes and nano electronics. In addition, magnesium oxide has moisture resistance and high melting point properties. In the present work has been carried out in the development of green crystalline powder of nickel doped magnesium oxide nanoparticles by Co-precipitation method, from the mixture of nickel chloride and magnesium chloride with KOH as solvent. From the XRD results, crystalline size of the particle can be observed. Spherical structure of Ni doped MgO nanoparticles were indicated by SEM results and powdered composition of samples were obtained from FTIR. EDAX represents the peak composition of the nanoparticle. The above analytical techniques have confirmed that the Ni doped MgO nanoparticles obtained from the mixture of NiCl2 and MgCl2.


2017 ◽  
Vol 68 (1) ◽  
pp. 168-171 ◽  
Author(s):  
Letitia Doina Duceac ◽  
Cristina Elena Dobre ◽  
Ioana Pavaleanu ◽  
Gabriela Calin ◽  
Simona Nichitus ◽  
...  

Preventing diseases is deemed to be the major goal of our century especially when an excessive fluoride in drinking water can cause dental fluorosis, bone stiffness, rheumatism and skeletal fluorosis. Fluoride uptake from groundwater implies a worldwide multidisciplinary effort in order to develop renewable, cheap, human friendly materials. Among other materials, hydrotalcites could be good candidates for an efficient fluoride removal from water due to their adsorption, anion exchange and reconstruction properties. These nanostructured materials were synthesized using co-precipitation method in controlled conditions. Presence of anions in the interlayer structure and morphological aspects were performed by FTIR and SEM techniques. Thermal treatment of hydrotalcites showed good adsorption capacities for water defluoridation mostly due to their tendency to restore the original structure.


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