Synthesis of Nitrogen-Doped Titanium Oxide Nanostructures Via a Surfactant-Free Hydrothermal Route

2005 ◽  
Vol 20 (11) ◽  
pp. 3011-3020 ◽  
Author(s):  
Chang Houn Rhee ◽  
Jae Sung Lee ◽  
Soo Hyun Chung
Keyword(s):  
Anatase Phase ◽  
High Surface ◽  
High Surface Area ◽  
Ammonium Ion ◽  
Molar Ratio ◽  
Titanium Oxides ◽  
Hydrothermal Conditions ◽  
Hydrothermal Route ◽  
Hydrothermal Temperature ◽  
Nitrogen Doped

Nitrogen-doped titanium oxides nanostructures were synthesized by a new method proposed here from titanium oxysulfate precursor in a NH4OH solution under hydrothermal conditions without any extra templates as structure driving agents. The material synthesized with NH4OH was an ammonium titanate and showed curled nanosheets, nanofibers or nanorods morphologies depending on the molar ratio of NH4OH to titanium precursor and the hydrothermal temperature. The nanofibrous titanates had a high surface area over 500 m2 g−1 and a pore volume of 0.72 cm3 g−1. The calcination of as-synthesized material at 673 K produced a titanium oxynitride TiO2−xNx with anatase phase, which absorbed visible light. Ion exchange of ammonium ion of the titanate with sodium Na2Ti3O7−xNx enhanced the thermal stability of the titanate phase.

Hydrothermal Synthesis and Characterization of Phosphor Doped Tetragonal Zirconia Nanocrystallites

2011 ◽  
Vol 197-198 ◽  
pp. 846-852
Author(s):  
Jian Jun Yin ◽  
Tao Wang ◽  
Wei Jing Xing
Keyword(s):  
Photoelectron Spectroscopy ◽  
Raw Materials ◽  
High Surface ◽  
High Surface Area ◽  
Tetragonal Zirconia ◽  
Zirconium Oxychloride ◽  
Dihydrogen Phosphate ◽  
Hydrothermal Conditions ◽  
Hydrothermal Temperature ◽  
X Ray

Using zirconium oxychloride hydrate ( ZrOCl2•8H2O) and ammonia water (NH3•H2O) as raw materials, and ammonium dihydrogen phosphate (NH4H2PO4) as additives, tetragonal zirconia (t-ZrO2) with size range of 8–12 nm were prepared by coprecipitation method under hydrothermal conditions. The influence factors on phase transformation and the particle size such as phosphor loading, hydrothermal temperature and calcination temperature were studied by X-ray diffraction (XRD), Fourier transform Roman spectra (FT-Roman), the Brunauer-Emmett-Teller (BET) method and X-ray photoelectron spectroscopy (XPS) techniques etc. Research results show that a small amount of phosphor has been incorporated into the framework of ZrO2 crystals, producing a certain amount of oxygen vacancies. Phosphor can effectively restrain crystal particles growth and improve the thermal stability of metastable t-ZrO2. The phosphor doped t-ZrO2 had a high surface area (244.2 m2/g). In contrast to the pure ZrO2 particles readily aggregating, the phosphor species deposited on the framework of ZrO2 crystals prevented the agglomeration of the primary particles during calcinations.

scholarly journals N-TiO2 synthesized by reflux method in H2O2-urea solution: point of zero charge, adsorption propertives, and photocatalytic activities under visible light

2015 ◽  
Vol 18 (1) ◽  
pp. 81-91
Author(s):  
Yen Thi Hai Huynh ◽  
Nhu Thi So Le
Keyword(s):  
Visible Light ◽  
Anatase Phase ◽  
High Surface ◽  
High Surface Area ◽  
Point Of Zero Charge ◽  
Urea Solution ◽  
Nitrogen Doped ◽  
Photocatalytic Activities ◽  
Solution Point ◽  
Low Crystalline

Nitrogen-doped TiO2 has been attractive because it showed photocatalytic activities under visible light. In this study, N-TiO2 was synthesized by refluxing gel TiO2 in the solutions of H2O2-urea. The influences of the concentration of urea and H2O2 solutions on photocatalytic activities of N-TiO2 were investigated. Samples were characterized by XRD, IR, pHPZC, BET, DRS. Adsorption and photocatalytic properties were studied by the degradation of methylene blue (MB) under visible light. The samples showed anatase phase with low crystalline, but high surface area. They had low pHPZC of 1-1.5, and adsorbed well cation dyes such as MB. When the concentration of urea increased from 1 M to 2 M, and 3 M, the adsorption capacity increased, but the photocatalysis decreased. Sample with the highest photocatalytic activity was obtained when refluxing in the solution containing 10 mL H2O2.

Hard-templating synthesis and enhanced photocatalysis of mesoporous titanium dioxides nanoparticles

2018 ◽  
Vol 11 (04) ◽  
pp. 1850077 ◽  
Author(s):  
K. L. Jin ◽  
X. J. Chen ◽  
J. C. Xu ◽  
Y. S. Huang ◽  
Y. B. Han ◽  
...  
Keyword(s):  
Surface Area ◽  
Anatase Phase ◽  
High Surface ◽  
High Surface Area ◽  
Mesoporous Structure ◽  
Photocatalytic Decomposition ◽  
Titanium Dioxides ◽  
Decomposition Efficiency ◽  
Templating Synthesis ◽  
Mb Adsorption

Mesoporous titanium dioxides nanoparticles (TiO2 NPs) were synthesized using activated carbon (AC) as templates after the decomposition of AC. All results indicated that TiO2 NPs with the small grain size presented the anatase phase structure. Mesoporous TiO2 NPs showed the high surface area and the surface area decreased with the TiO2 content. The removal of methylene blue (MB) indicated that the photocatalytic decomposition efficiency of mesoporous TiO2 NPs increased up to 92% for three-times doping with the TiO2 content, and then decreased. This should be attributed to the synergistic effect from the MB adsorption of mesoporous-structure and the photocatalysis of TiO2 NPs. Therefore, the higher MB concentration near TiO2 NPs from the mesoporous-structure increased the touch chance and the MB photocatalytic decomposition was promoted greatly.

Aqueous colloidal sol–gel route to synthesize nanosized ceria-doped titania having high surface area and increased anatase phase stability

2007 ◽  
Vol 43 (3) ◽  
pp. 299-304 ◽  
Author(s):  
Pradeepan Periyat ◽  
K. V. Baiju ◽  
P. Mukundan ◽  
P. Krishna Pillai ◽  
K. G. K. Warrier
Keyword(s):  
Surface Area ◽  
Phase Stability ◽  
Anatase Phase ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Doped Titania

Preparation of Al2O3 Whiskers from AACH Using Hydrothermal Method and its Use for the Removal of Lead Ions by Adsorption

2021 ◽  
Vol 875 ◽  
pp. 177-183
Author(s):  
Asma Ameer ◽  
Syed Mujtaba Ul Hassan ◽  
Syed M. Husnain ◽  
Jamil Ahmad ◽  
Faisal Shahzad ◽  
...  
Keyword(s):  
High Surface ◽  
High Surface Area ◽  
Heavy Ion ◽  
Lead Ions ◽  
Hydrothermal Route ◽  
Adsorption Parameters ◽  
Ion Removal ◽  
Equilibrium Data ◽  
Different Temperatures ◽  
Adsorption Equilibrium Data

This work explores the potential of adsorption of Pb2+ by hydrothermally synthesized alumina. In comparison to other heavy ion removal techniques, adsorption is preferred in the current study as it has the edge of ease of operation and environment friendly characteristics. Synthesis of high surface area alumina whiskers was achieved by hydrothermal route which were subsequently employed for the active adsorption of lead ions. AACH (Ammonium Aluminum Carbonate Hydroxide), used as precursor for alumina, was calcined at three different temperatures i.e. 700, 900 and 1100 °C to form alumina whiskers. These whiskers were characterized by XRD, SEM, BET and FTIR. Various adsorption parameters such as contact time, pH, initial metal concentration were studied for lead ions. Maximal removal efficiency was obtained for the specimen having pH 4 and calcined at 700 °C for 60 minutes. Kinetic data was best described by pseudo second order model, whereas the adsorption equilibrium data obeyed the Langmuir adsorption isotherm model.

Sol-Gel Precursors and the Oxygen Storage Capacity of PrOy-ZrO2 Materials

1997 ◽  
Vol 497 ◽  
Author(s):  
C. K. Narula ◽  
K. L. Taylor ◽  
L. P. Haack ◽  
L. F. Allard ◽  
A. Datye ◽  
...  
Keyword(s):  
Single Phase ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Fluorite Structure ◽  
Oxygen Storage Capacity ◽  
Oxygen Storage ◽  
Molar Ratio ◽  
Metal Nitrates ◽  
Temperature Programmed

ABSTRACTThe gels derived from mixtures of Pr(OiC3H7)3 and Zr(OiC3H7)4•iC3H7OH, upon hydrolysis and pyrolysis, furnish single-phase PrOy-ZrO2 materials crystallized in the fluorite structure. These materials can be coated onto high-surface-area γ-alumina powders or deposited onto dense α-alumina coupons in the form of thin films from a solution of parent alkoxides modified with 2,4-pentanedione in THF. The fluorite structure of the PrOy-ZrO2 in the films appears to be thermally stable in air up to 1200°C. Temperature-programmed-reduction (TPR) measurements show that the bulk PrOy-ZrO2 material with a Pr. Zr molar ratio of 1:1 can store and release oxygen while that with a molar ratio of 1:3 cannot.The precursors play an important role in determining phase composition of the resulting PrOy-ZrO2 material. A mixture of monoclinic and cubic or tetragonal phases was found in PrOy-ZrO2 prepared from a new single-source heterometallic alkoxide, Pr2Zr6(μ4-O)2(μ-OAc)6(μ-OiPr)10(OiPr)10, whereas a mixture of cubic and tetragonal phases was present in PrOy-ZrO2 made previously by coprecipitation from aqueous solutions of the metal nitrates.

Preparation of Highly Crystalline Mesoporous TiO2 by Using Carbon to Protect the Pore Structure at Elevated Temperature

2010 ◽  
Vol 654-656 ◽  
pp. 2406-2409
Author(s):  
Yu Dan Zhu ◽  
Yu Lan Ding ◽  
Xiao Hua Lu ◽  
Wei Zhuang ◽  
Ling Hong Lu
Keyword(s):  
Elevated Temperature ◽  
Pore Structure ◽  
Anatase Phase ◽  
High Surface ◽  
Catalyst Support ◽  
High Surface Area ◽  
Pore Wall ◽  
Mesoporous Tio2 ◽  
Mesopore Structure ◽  
Novel Strategy

Mesoporous TiO2 with highly crystalline pore wall has an enormous potential for applications in photocatalysis, catalyst support, drug delivery, etc. However, with the sintering temperature increasing, the crystallinity of the pore wall increases while the mesopore structure tends to collapse. In this work, we presented a novel strategy for creating highly crystalline mesoporous TiO2 (MT800) by using carbon to protect the pore structure at elevated temperature. The structural characterization indicates that MT800 has highly crystalline anatase phase and processes high surface area. The photocatalysis performance was evaluated by organic degradation and the results show that MT800 has superior photocatalysis activity to the TiO2 (T800) calcined at 800°C without carbon, because of the synergies of crystallinity and mesostructure.

Synthesis of Nanoporous Materials Al-MCM-41 from Natural Halloysite

NANO ◽  
2015 ◽  
Vol 10 (01) ◽  
pp. 1550005 ◽  
Author(s):  
Yaling Xie ◽  
Aidong Tang ◽  
Huaming Yang
Keyword(s):  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Halloysite Nanotubes ◽  
Nanoporous Materials ◽  
Molar Ratio ◽  
Molar Ratios ◽  
Naoh Solution ◽  
The One ◽  
Mcm 41

Nanoporous materials Al -MCM-41 with varying Si / Al molar ratios have been successfully synthesized from natural clay mineral halloysite nanotubes (HNTs). Hydrothermal treatment of acid-pretreated HNTs and NaOH solution resulted in the one-step synthesis of final nanoporous products by using surfactant. The effects of Si / Al molar ratios (7.7, 61.0 and 176.5) on the surface area, porosity and degree of structural order of Al -MCM-41 materials have been investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), N 2 adsorption–desorption measurements and Fourier transform infrared (FTIR) spectra techniques. The results indicated that Si / Al molar ratio had important effect on the characteristics of nanoporous materials, and Al -MCM-41 with an intermediate Si / Al molar ratio of 61.0 exhibited excellent characteristics with high degree of order, high surface area (S BET ) of 1033 m2/g and pore volume of 0.92 mL/g.

Facile Fabrication of Single Crystalline Ceria Nanoparticles for Photo-Responsive Applications

2012 ◽  
Vol 734 ◽  
pp. 127-137
Author(s):  
D.P. Das ◽  
Armita Dash ◽  
B.K. Mishra
Keyword(s):  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Band Gap Energy ◽  
Ceria Nanoparticles ◽  
Processing Conditions ◽  
Hydrothermal Route ◽  
Single Crystalline ◽  
Nanocrystallite Size ◽  
Facile Fabrication

The present investigation is about fabrication of single-crystalline ceria (CeO2) nanoparticle by a hydrothermal route. High surface area CeO2 was synthesized with transformation of morphology from nanofibers to nanocubes in response to processing conditions. A steady variation of average nanocrystallite size ca. in the range 3.0-16.9 nm and a range of band gap energy from 2.6 to 2.9 eV were measured. The surface area of the nanoparticles varied in the range 16.0136.1 m2/g and the variation in surface area is attributed to the nature of packing of particles. The ceria nanofibers could generate 870.5 µmol of H2 in 3 h of irradiation.

Sign in / Sign up

Export Citation Format

Share Document