Research on Solvothermal Synthesis of Phase Composition Controllable Nanocrystalline TiO2 Powders

2011 ◽  
Vol 284-286 ◽  
pp. 820-824
Author(s):  
Mei Jun Li ◽  
Wen Bin Cao
Keyword(s):  
Aqueous Solution ◽  
Grain Size ◽  
Phase Composition ◽  
Absorption Edge ◽  
Photoelectron Spectroscopy ◽  
Solvothermal Synthesis ◽  
X Ray ◽  
Light Yellow ◽  
Photocatalytic Activities ◽  
Visible Light Photocatalytic

N-doped TiO2 powders have been prepared by solvothermal synthesis using TiCl3 aqueous solution as precursor. The as-synthesized powders are composed of anatase and rutile and show light-yellow in color. The grain size is ranged from 10.3 nm to 19.1 nm by Scherrer's method and the specific surface area is ranged from 21 m2/g to 122 m2/g. X-ray photoelectron spectroscopy (XPS) results indicate that N atoms have been doped into the lattice of TiO2. Ti-N bonding and radical groups such as ×OH were detected on the surface of the powders. The synthesized N-doped TiO2 powders shows excellent visible-light photocatalytic activities and their absorption edge have been red-shifted to 560 nm.

scholarly journals Preparation of Tin Oxide Quantum Dots in Aqueous Solution and Applications in Semiconductor Gas Sensors

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 240 ◽  
Author(s):  
Jianqiao Liu ◽  
Weiting Xue ◽  
Guohua Jin ◽  
Zhaoxia Zhai ◽  
Jiarong Lv ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Quantum Dots ◽  
Grain Size ◽  
Gas Sensors ◽  
Tin Oxide ◽  
Photoelectron Spectroscopy ◽  
Fluorescence Emission ◽  
X Ray ◽  
Average Grain Size ◽  
Semiconductor Gas Sensors

Tin oxide quantum dots (QDs) were prepared in aqueous solution from the precursor of tin dichloride via a simple process of hydrolysis and oxidation. The average grain size of QDs was 1.9 nm. The hydrothermal treatment was used to control the average grain size, which increased to 2.7 and 4.0 nm when the operating temperatures of 125 and 225 °C were employed, respectively. The X-ray photoelectron spectroscopy (XPS) spectrum and X-ray diffraction analysis (XRD) pattern confirmed a rutile SnO2 system for the QDs. A band gap of 3.66 eV was evaluated from the UV-VIS absorption spectrum. A fluorescence emission peak was observed at a wavelength of 300 nm, and the response was quenched by the high concentration of QDs in the aqueous solution. The current-voltage (I-V) correlation inferred that grain boundaries had the electrical characteristics of the Schottky barrier. The response of the QD thin film to H2 gas revealed its potential application in semiconductor gas sensors.

scholarly journals Hydrothermal Synthesis of Iodine-Doped Nanoplates with Enhanced Visible and Ultraviolet-Induced Photocatalytic Activities

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Jiang Zhang ◽  
Zheng-Hong Huang ◽  
Yong Xu ◽  
Feiyu Kang
Keyword(s):  
Photocatalytic Activity ◽  
Photoelectron Spectroscopy ◽  
Oxygen Vacancies ◽  
Diffuse Reflectance Spectroscopy ◽  
Synergetic Effect ◽  
X Ray Diffraction ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Photocatalytic Activities

The iodine-doped Bi2WO6(I-BWO) photocatalyst was prepared via a hydrothermal method using potassium iodide as the source of iodine. The samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM) and selected area electron diffraction (SAED), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy (DRS), and photoluminescence (PL) spectroscopy. The photocatalytic activity of I-BWO for the degradation of rhodamine B (RhB) was higher than that of pure BWO and I2-BWO regardless of visible light (>420 nm) or ultraviolet light (<400 nm) irradiation. The results of DRS analysis showed that the I-BWO and I2-BWO catalysts had narrower band gaps. XPS analysis proved that the multivalent iodine species including I0and were coadsorbed on the defect surface of Bi2WO6in I-BWO. The enhanced PL intensity revealed that a large number of defects of oxygen vacancies were formed by the doping of iodine. The enhanced photocatalytic activity of I-BWO for degradation of RhB was caused by the synergetic effect of a small crystalline size, a narrow band gap, and plenty of oxygen vacancies.

scholarly journals Succinic acid in aqueous solution: connecting microscopic surface composition and macroscopic surface tension

2014 ◽  
Vol 16 (39) ◽  
pp. 21486-21495 ◽  
Author(s):  
Josephina Werner ◽  
Jan Julin ◽  
Maryam Dalirian ◽  
Nønne L. Prisle ◽  
Gunnar Öhrwall ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Surface Tension ◽  
Succinic Acid ◽  
Photoelectron Spectroscopy ◽  
Surface Composition ◽  
Md Simulations ◽  
Vapor Interface ◽  
X Ray ◽  
Ph Values ◽  
Microscopic Surface

The water–vapor interface of aqueous solutions of succinic acid, where pH values and bulk concentrations were varied, has been studied using surface sensitive X-ray photoelectron spectroscopy (XPS) and molecular dynamics (MD) simulations.

scholarly journals Effect of synthesis conditions  on  methylene blue adsorption capacity of electrochemically preparated graphene

2020 ◽  
Vol 9 (3) ◽  
pp. 9-14
Author(s):  
Hao Pham Van ◽  
Linh Ha Xuan ◽  
Oanh Phung Thi ◽  
Hong Phan Ngoc ◽  
Huy Nguyen Nhat ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Methylene Blue ◽  
Adsorption Capacity ◽  
Functional Groups ◽  
Photoelectron Spectroscopy ◽  
Graphene Nanosheets ◽  
Electrochemical Exfoliation ◽  
X Ray ◽  
Synthesis Conditions ◽  
Mb Adsorption

This report presents the effect of synthesis conditions on the synthesis of graphene nanosheets via electrochemical exfoliation method for adsorbing methylene blue from aqueous solution. Oxygen-containing functional groups and defects in the material were characterized by Raman and X-ray photoelectron spectroscopy (XPS). As a result, by using voltage of 15 V, (NH4)2SO4 (5%, 250 mL) and KOH (7.5%, 250 mL), the obtained material showed the highest MB adsorption capacity due to the high densities of oxygen-containing groups and defects comparison to other conditions.

scholarly journals Synthesis of Nanoscale Zerovalent Iron (nZVI) Supported on Biochar for Chromium Remediation from Aqueous Solution and Soil

2019 ◽  
Vol 16 (22) ◽  
pp. 4430 ◽  
Author(s):  
Haixia Wang ◽  
Mingliang Zhang ◽  
Hongyi Li
Keyword(s):  
Aqueous Solution ◽  
Photoelectron Spectroscopy ◽  
Zero Valent Iron ◽  
Zerovalent Iron ◽  
X Ray ◽  
Nanoscale Zerovalent Iron ◽  
Before And After ◽  
Pseudo Second Order ◽  
Xrd Patterns ◽  
Co Precipitation

Maize straw biochar-supported nanoscale zero-valent iron composite (MSB-nZVI) was prepared for efficient chromium (Cr) removal through alleviating the aggregation of zero-valent iron particles. The removal mechanism of MSB-nZVI was investigated by scanning electron microscopy with energy dispersive X-ray (SEM-EDX), X-ray diffractometry (XRD), and X-ray photoelectron spectroscopy (XPS). Cr(VI) removal from aqueous solution by MSB-nZVI was greatly affected by pH and initial concentration. The removal efficiency of Cr(VI) decreased with increasing pH, and the removal kinetics followed the pseudo-second-order model. XRD patterns of MSB-nZVI before and after reaction showed that reduction and precipitation/co-precipitation (FeCr2O4, Fe3O4, Fe2O3) occurred with the conversion of Cr(VI) to Cr(III) and Fe(0) to Fe(II)/Fe(III). The produced precipitation/co-precipitation could be deposited on the MSB surface rather than being only coated on the surface of nZVI particles, which can alleviate passivation of nZVI. For remediation of Cr(VI)-contaminated saline–alkali soil (pH 8.6–9.0, Cr 341 mg/kg), the released amount of Cr(VI) was 70.7 mg/kg, while it sharply decreased to 0.6–1.7 mg/kg at pH 4.0–8.0, indicating that the saline–alkali environment inhibited the remediation efficiency. These results show that MSB-nZVI can be used as an effective material for Cr(VI) removal from aqueous solution and contaminated soil.

Preparation and Characterization of Carbon Nanotubes/Al2O3 Inorganic Hybrid Material - A Bio-Inspired Poly(Dopamine) Approach

2018 ◽  
Vol 54 ◽  
pp. 127-135
Author(s):  
Wen Zhao ◽  
Wen Cai Wang ◽  
Yong Lai Lu ◽  
Li Qun Zhang
Keyword(s):  
Carbon Nanotubes ◽  
Aqueous Solution ◽  
Photoelectron Spectroscopy ◽  
Oxidative Polymerization ◽  
The Self ◽  
Liquid Phase Deposition ◽  
X Ray ◽  
Transmission Electron ◽  
Cnts Surface

Carbon nanotubes/alumina (CNTs/Al2O3) nanocomposites were prepared by the poly (dopamine) assisted chemical liquid phase deposition (CLPD). The poly (dopamine) layers were firstly coated on the CNTs surface uniformly by the self-oxidative polymerization of dopamine in mild aqueous solution and then the Al2O3 nanoparticles formed on the poly (dopamine) coated CNTs surface by the CLPD. The hydrophilic poly (dopamine) layers on the CNTs surface can improve the dispersion of CNTs in aqueous solution. Moreover, it can be used as a key linker between the CNTs and Al2O3 because of the nitrogen-containing group in poly (dopamine) could coordinate with Al3+ ions. The as-prepared poly (dopamine) coated CNTs and CNTs/Al2O3 nanohybrids were characterized by X-ray photoelectron spectroscopy (XPS), X-radial diffractometer (XRD) and high resolution transmission electron microscopy (HRTEM). These results showed that the poly (dopamine) layers were coated on the surface of CNTs uniformly, and the Al2O3 nanoparticles embellished with the poly (dopamine) coated CNTs surface. Compared with pristine NR composites, the thermal conductivity of the as-prepared NR/CNTs@Al2O3 composites increased 17%.

scholarly journals SBA-16 Cage-Like Porous Material Modified with APTES as an Adsorbent for Pb2+ Ions Removal from Aqueous Solution

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 927 ◽  
Author(s):  
Viviana Palos-Barba ◽  
Abigail Moreno-Martell ◽  
Verónica Hernández-Morales ◽  
Carmen L. Peza-Ledesma ◽  
Eric M. Rivera-Muñoz ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Photoelectron Spectroscopy ◽  
Contact Time ◽  
Diffuse Reflectance Spectroscopy ◽  
Cell Structure ◽  
Textural Properties ◽  
Batch Adsorption ◽  
X Ray ◽  
Ion Removal ◽  
Transmission Electron

Tridimensional cubic mesoporous silica, SBA-16, functionalized with aminopropyl groups, were employed as adsorbents for Pb2+ ion removal from aqueous solution. The adsorption capacity was investigated for the effect of pH, contact time, temperature, and concentration of 3-aminopropyltriethoxysilane (APTES) employed for adsorbent functionalization. The textural properties and morphology of the adsorbents were evaluated by N2 physisorption, small-angle X-ray diffraction (XRD), diffuse reflectance spectroscopy (UV-vis), and transmission electron microscopy (TEM). The functionalization of the SBA-16 was evaluated by elemental analysis (N), thermogravimetric analysis (TG), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). Batch adsorption studies show that the total Pb2+ ions removal was archived on adsorbent having an optimized amount of aminopropyl groups (2N-SBA-16). The maximum of Pb2+ ions removal occurred at optimized adsorption conditions: pH = 5–6, contact time 40 min, and at a low initial lead concentration in solution (200 mg L−1). Under the same adsorption conditions, the amino-functionalized SBA-16 with cubic 3D unit cell structure exhibited higher adsorption capability than its SBA-15 counterpart with uniform mesoporous channels.

scholarly journals Removal Efficiency and Mechanism of Cr(VI) from Aqueous Solution by Maize Straw Biochars Derived at Different Pyrolysis Temperatures

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 781 ◽  
Author(s):  
Wang ◽  
Zhang ◽  
Lv
Keyword(s):  
Aqueous Solution ◽  
Removal Efficiency ◽  
Photoelectron Spectroscopy ◽  
Low Cost ◽  
X Ray ◽  
Removal Capacity ◽  
Maize Straw ◽  
Efficient Adsorbent ◽  
Positively Charged ◽  
Maximum Removal

The removal efficiency and mechanism of Cr(VI) removal from aqueous solution on semi-decomposed maize straw biochars pyrolyzed at 300 to 600 °C were investigated. The removal of Cr(VI) by the biochars decreased with pyrolysis temperature increasing from 300 to 600 °C, and the maximum removal capacity of Cr(VI) for maize straw biochar pyrolyzed at 300 °C was 91 mg/g at pH 2.0. The percentage removal of Cr(VI) rapidly decreased with pH increasing from 2.0 to 8.0, with the maximum (>99.9%) at pH 2.0. The variation of Cr(VI) and Cr(III) concentrations in the solution after reaction showed that Cr(VI) concentration decreased while Cr(III) increased and the equilibrium was reached after 48 h, while the redox potential after reaction decreased due to Cr(VI) reduction. X-ray photoelectron spectroscopy (XPS) semi-quantitative analysis showed that Cr(III) accounted for 75.7% of the total Cr bound to maize straw biochar, which indicated reductive adsorption was responsible for Cr(VI) removal by the biochars. Cr(VI) was firstly adsorbed onto the positively charged biochar surface and reduced to Cr(III) by electrons provided by oxygen-containing functional groups (e.g., C=O), and subsequently part of the converted Cr(III) remained on the biochar surface and the rest released into solution. Fourier transform infrared (FTIR) data indicated the participation of C=O, Si–O, –CH2 and –CH3 groups in Cr(VI) removal by the biochars. This study showed that maize straw biochar pyrolyzed at 300 °C for 2 h was one low-cost and efficient adsorbent for Cr(VI) removal from aqueous solution.

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