Photocatalytic decoloration of Acid Red 27 in presence of SnO2 nanoparticles

2010 ◽  
Vol 62 (6) ◽  
pp. 1256-1264 ◽  
Author(s):  
A. Esmaielzadeh Kandjani ◽  
M. Farzalipour Tabriz ◽  
N. A. Arefian ◽  
M. R. Vaezi ◽  
F. Halek ◽  
...  
Keyword(s):  
Rate Constant ◽  
Sno2 Nanoparticles ◽  
High Surface ◽  
Hydrothermal Process ◽  
High Surface Area ◽  
Reaction Rate Constant ◽  
Kinetic Rate Constant ◽  
Kinetic Rate ◽  
Surface Areas ◽  
Crystallite Sizes

In this paper, the photocatalytic decoloration of Acid Red 27 (AR27) has been investigated using ultraviolet (UV) irradiation in presence of SnO2 nanoparticles. SnO2 nanoparticles were synthesized via hydrothermal process. The SnO2 nanoparticles' average crystallite sizes derived from X-ray analyses which were synthesized for 2, 12 and 24 hrs were about 3.73, 5.31 and 7.6 nm, respectively. Brunauer-Emmett-Teller (BET) analyses showed high surface area of about 183, 120 and 90(m2/g), respectively for aforementioned synthesized samples. Our investigations indicated that reaction rate constant and photocatalytic efficiency of AR27 decoloration have a direct relation with SnO2 nanoparticles' specific surface areas and band gap energies. Decoloration kinetics was investigated by using Langmuir–Hinshelwood model. The values of the adsorption equilibrium constant, K[AR27], and the kinetic rate constant of surface reaction, kc, were found to be 0.0924 (l/mg) and 0.2535 (mg/l min), respectively.

Efficiency Enhancement in Dye-Sensitized Solar Cell Using TiO2 /Ilmenite-Derived Nanofiber Composite as Working Electrode

2014 ◽  
Vol 925 ◽  
pp. 600-604
Author(s):  
Athapon Simpraditpan ◽  
Thanakorn Wirunmongkol ◽  
Sorapong Pavasupree ◽  
Wisanu Pecharapa
Keyword(s):  
Nanocomposite Film ◽  
High Surface ◽  
Hydrothermal Process ◽  
High Surface Area ◽  
Dye Sensitized Solar Cells ◽  
Nanocomposite Films ◽  
Film Electrode ◽  
Photoelectric Conversion ◽  
Dye Sensitized ◽  
Working Electrode

TiO2 nanocomposite films of calcined TiO2 nanofibers and commercial-grade TiO2 nanoparticles Degussa (P25) utilized as working electrode of dye-sensitized solar cells (DSSCs) are prepared by a doctor blade method. TiO2 nanofibers were synthesized from ilmenite mineral by hydrothermal process in combination with calcinations process. The prepared samples are characterized by XRD, XPS and TEM. The photoelectric conversion performance of the DSSC based on nanocomposite film electrode was compared to the device fabricated by pure P25 at the same film thickness. The result shows that as calcination temperature increases, the transformation of nanofibers to nanorods and nanoparticles were observed. The energy conversion efficiency (ƞ) of the device tends to with increasing calcined temperature. The greatest ƞ is 3.90% obtained from DSSC fabricated from nanocomposite film electrode of 5 wt.% nanofibers calcined at 800 oC for 2 h mixed with P25, indicating the significant enhancement in its performance by the incorporation of the nanofibers. This enhancement of DSSCs may correlate to high surface area, higher light scattering and light harvesting, low charge recombination and fast electron-transfer rate by nanofibers.

Synthesis and Characterization of Aerogel-derived Cation-substituted Hexaaluminates

1996 ◽  
Vol 457 ◽  
Author(s):  
Lin-chiuan Yan ◽  
Levi T. Thompson
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Catalytic Combustion ◽  
High Surface ◽  
High Surface Area ◽  
Synthesis And Characterization ◽  
New Methods ◽  
Surface Areas ◽  
Different Characteristics

ABSTRACTNew methods have been developed for the synthesis of high surface area cation-substituted hexaaluminates. These materials were prepared by calcining high temperature (ethanol extraction) or low temperature (CO2 extraction) aerogels at temperatures up to 1600°C. Cation-substituted hexaaluminates have emerged as promising catalysts for use in high temperature catalytic combustion. In comparing unsubstituted and cation-substituted hexaaluminates, we found that the phase transformations were much cleaner for the cation-substituted materials. BaCO3 and BaAl2O4 were intermediates during transformation of the unsubstituted materials, while the cation-substituted materials transformed directly from an amorphous phase to crystalline hexaaluminate. Moreover, the presence of substitution cations caused the transformation to occur at lower temperatures. Mn seems to be a better substitution cation than Co since the Mn-substituted materials exhibited higher surface areas and better heat resistances than the Co-substituted materials. The low temperature aerogel-derived materials possessed quite different characteristics from the high temperature aerogel-derived materials. For example, phase transformation pathways were different.

In situ carbonization of a soft-template to directly synthesize crystalline mesoporous metal oxides with high surface areas

2014 ◽  
Vol 38 (12) ◽  
pp. 5846-5855 ◽  
Author(s):  
Limin Guo ◽  
Shintaro Ida ◽  
Takashi Daio ◽  
Hidehisa Hagiwara ◽  
Tatsumi Ishihara
Keyword(s):  
High Surface ◽  
Tantalum Oxide ◽  
High Surface Area ◽  
Soft Template ◽  
Block Polymer ◽  
Surface Areas ◽  
Mesoporous Metal Oxides ◽  
Mesoporous Metal ◽  
In Situ Carbonization

High-surface-area crystalline mesoporous tantalum oxide has been successfully synthesized using a pluronic tri-block polymer as the template.

scholarly journals Surface and Catalytic Properties of NiO–Fe2O3 Solids Supported on Al2O3

1996 ◽  
Vol 13 (5) ◽  
pp. 409-421 ◽  
Author(s):  
G.A. El-Shobaky ◽  
A.M. Ghozza ◽  
N.M. Deraz
Keyword(s):  
Rate Constant ◽  
Reaction Rate ◽  
Catalytic Properties ◽  
Unit Area ◽  
Surface Characteristics ◽  
Reaction Rate Constant ◽  
Oxidation Of Co ◽  
Catalytic Activities ◽  
Surface Areas ◽  
Specific Surface Areas

A series of NiO–Fe2O3 catalysts supported on γ-Al2O3 was prepared. The effect of the NiO and Fe2O3 contents and the precalcination temperature on the surface and catalytic properties of the various solids has been investigated. The surface characteristics, viz. SBET, Vp and r, were determined using N2 adsorption conducted at –196°C. The catalytic activities of the various solids were studied using the oxidation of CO by O2 at temperatures in the range between 150°C and 400°C. The prepared solids were preheated in air at various temperatures between 400°C and 1000°C. The results obtained revealed that the SBET values of the different solids decrease progressively on increasing the precalcination temperature above 400°C due to sintering. The specific surface areas were also found to decrease on increasing both the NiO and Fe2O3 contents. The catalytic activities, expressed as reaction rate constant (k) and reaction rate constant per unit area (k), were found to decrease on increasing the precalcination temperature in the range 400–1000°C. Furthermore, the amounts of NiO and Fe2O3 in the different solids modified their catalytic activities in different manners.

Preparation of CuCrO2 Powders with High Surface Areas

2014 ◽  
Vol 617 ◽  
pp. 187-190 ◽  
Author(s):  
Te Wei Chiu ◽  
Yi Wei Feng
Keyword(s):  
Nitric Acid ◽  
Surface Area ◽  
Chemical Treatment ◽  
High Surface ◽  
High Surface Area ◽  
Phase Evolution ◽  
Surface Areas ◽  
Pure Phase ◽  
Cu Ions

In this study, the effects of glycine-nitrate ratios and postcombustion chemical treatment on the phase evolution and surface area of CuCrO2powders were investigated. The pure phase of CuCrO2powders was obtained at a glycine-nitrate ratio of 1.2–1.4. When the glycine-nitrate ratio was higher than 1.9, the Cu ions were reduced to Cu(0) and the phase of Cu metal and Cr2O3were observed. However, when the glycine-nitrate ratio was lower than 1.1, the Cu ions were partially maintained as Cu(2+), and a bluish residue was observed. As-combusted CuCrO2powder with a high surface area (50 m2/g) was obtained at a glycine-nitrate ratio of 1.2. Furthermore, a high surface area (> 60 m2/g) was obtained by leaching as-combusted CuCrO2powder with diluted nitric acid.

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