Preparation, Characterization and Photocatalysis Properties of Ultrafine Perovskite-Type LaCoO3

2011 ◽  
Vol 197-198 ◽  
pp. 935-942
Author(s):  
Xia Fu ◽  
Yang Chen ◽  
Gao Qi Yu ◽  
Chao Yu ◽  
Hou Zhi Wang ◽  
...  
Keyword(s):  
Supercritical Fluid ◽  
Mixed Oxides ◽  
Uv Light ◽  
Sol Gel ◽  
Raw Material ◽  
Supercritical Fluid Drying ◽  
Photocatalytic Activities ◽  
Ft Ir ◽  
Drying Technology ◽  
Perovskite Type

Using La2O3and Co(NO3)2•6H2O as raw material, ultrafine perovskite-type oxides LaCoO3was prepared by Supercritical Fluid Drying Technology and Sol-Gel method. The prepared materials’ crystal structure and morphology were characterized by TG-DTA、XRD、FT-IR and TEM. The photocatalytic activity of ultrafine LaCoO3powders was evaluated by degradation of methyl orange (MO) solution under 15W UV light irradiation. The results show: At 250°C , the amorphous ultrafine La-Co particles with the size less than 10 nm can be obtained by Supercritical Fluid Drying Technology. At 850°C , the size of the particles increased to 15-35nm, the nanocrystalline LaCoO3had a perfect rhombohedral perovskite structure. At 900°C , the crystalline phases of the lanthanum-cobalt mixed oxides were LaCoO3and La2O3, and the amorphous component is Co2O3, the presence of lanthanum affects the crystallization of cobalt oxides. The LaCoO3has excellent photocatalytic activities and 100% MO solution was decolorized only after 4h.

Preparation and Characterization of Nanometer Iron Oxide by Sol-Gel Method and Supercritical Fluid Drying Technology

2008 ◽  
Vol 368-372 ◽  
pp. 617-619 ◽  
Author(s):  
Yu Zhang ◽  
Jian Xin Cao ◽  
Deng Pan Nie ◽  
Fei Liu ◽  
Yong Gang Dong
Keyword(s):  
Magnetic Properties ◽  
Iron Oxide ◽  
Supercritical Fluid ◽  
Sol Gel ◽  
Gel Method ◽  
Sol Gel Method ◽  
Supercritical Fluid Drying ◽  
Heat Treated ◽  
One Step ◽  
Drying Technology

Iron oxide nanometer powders were prepared by using sol-gel method and the supercritical fluid drying technology (SCFD) from inorganic salts. The characteristics of the iron oxide nanometer powders were characterized systematically. The results showed that the drying and crystallization of the production could be achieved in one step by SCFD method; furthermore, a highly dispersed, size uniformed and with better crystallization magnetite (Fe3O4) nanoparticles can be obtained. Phase transformation of the as-synthesized powders occurs at about 80°C, and only hematite (α-Fe2O3) can be obtained when being heated at temperatures higher than 400°C. The production synthesized by SCFD exhibits significant magnetic properties. As the heat-treated temperature increase, the magnetic properties of the sample decrease gradually.

Synthesis and physicochemical properties of graphene/ZrO2 composite aerogels

RSC Advances ◽  
2015 ◽  
Vol 5 (16) ◽  
pp. 11738-11744 ◽  
Author(s):  
Dongman Guo ◽  
Yun Lu ◽  
Yibo Zhao ◽  
Xuetong Zhang
Keyword(s):  
Physicochemical Properties ◽  
Supercritical Fluid ◽  
Sol Gel ◽  
Drying Process ◽  
Gel Method ◽  
Sol Gel Method ◽  
Supercritical Fluid Drying ◽  
Composite Aerogels

Graphene/ZrO2 composite aerogels with large BET areas have been synthesized using a sol–gel method together with a supercritical fluid drying process.

Effect of Complexing Agent on Morphology and Crystal Structure of La1-xCexCoO3 (x=0, 0.2, and 0.4) Perovskite-Type Mixed Oxides Catalyst Prepared by Sol-Gel Method

2010 ◽  
Vol 658 ◽  
pp. 29-32 ◽  
Author(s):  
Kanit Soongprasit ◽  
Duangdao Aht-Ong ◽  
Viboon Sricharoenchaikul ◽  
Duangduen Atong
Keyword(s):  
Crystal Structure ◽  
Polyvinyl Alcohol ◽  
Mixed Oxides ◽  
Sol Gel ◽  
Value Added ◽  
Molar Ratio ◽  
Complexing Agent ◽  
Nitrate Hexahydrate ◽  
Mixed Oxide Catalysts ◽  
Perovskite Type

. La1-xCexCoO3 (x=0, 0.2, and 0.4) perovskite-type mixed oxides using polyvinyl alcohol (PVA) as complexing agent at two molar ratio of metal ion to PVA (1:1 and 1:2) were successfully prepared by sol-gel process. The precursor included lanthanum (II) nitrate hexahydrate, cerium (II) nitrate hexahydrate, and cobalt (II) nitrate hexahydrate where polyvinyl alcohol was added as complexing agent. The suitable condition of Cerium (Ce) substitution and PVA molar ratio were established for further application in hydrocarbon conversion to high value added products. TGA thermogram of as-prepared precursor showed that PVA absolutely decomposed at temperature higher than 500°C. XRD patterns of calcined catalyst showed both LaCoO3 rhombohedral and CeO2 cubic structures that confirmed the formation of mixed crystal structure. Nevertheless, Co3O4 slightly appeared with low peak intensity which came from the oxidation reaction of as-prepared catalyst during calcinations. XRD showed that PVA did not effect to crystal structure of synthesized catalyst. Higher PVA content added in the precursor cause the reduction of crystal growth of catalyst in calcinations step. In contrast, morphology of catalyst is directly related with PVA content such that the spongy and sheet-like structure were formed with increasing PVA content which prevented the agglomeration of particles. The results showed that PVA content play an important role in morphology of perovskite-type mixed oxide catalysts but did not affected to their crystal structures.

Preparation and Photocatalytic Activity of TiO2/Opal Composite

2013 ◽  
Vol 668 ◽  
pp. 13-16
Author(s):  
Qing Shan Li ◽  
Biao Zhan ◽  
Wei Hong ◽  
Guang Zhong Xing
Keyword(s):  
Methylene Blue ◽  
Uv Light ◽  
Sol Gel ◽  
Tetrabutyl Titanate ◽  
Methylene Blue Solution ◽  
Photocatalytic Decolorization ◽  
Uv Light Irradiation ◽  
Photocatalytic Activities ◽  
Blue Solution ◽  
Gel Technique

Opal as a carrier, tetrabutyl titanate as a titanium source, TiO2 loaded on opal was prepared by sol-gel technique. The photocatalysts were characterized by XRD, TEM and UV-VIS absorption spectrum. Their photocatalytic activities were examined by the photocatalytic decolorization of methylene blue solution under UV light irradiation. The effects of calcination temperature, the amount of TiO2 loading and pH on photocatalytic activities were discussed. The results show that TiO2 supported on opal induced enhancement of photocatalytic decolorization rant and TiO2 doping is about 30 wt. % with 92.15% of decolorization rate at 700°C.

Study on Preparation and Photocatalytic Performance of Co-Doped TiO2 with Cu and Ce

2011 ◽  
Vol 399-401 ◽  
pp. 722-726 ◽  
Author(s):  
Jiang Ping Zhao ◽  
Xiao Ni Yang ◽  
Hao Zhang
Keyword(s):  
Photocatalytic Performance ◽  
Sol Gel ◽  
Test Chamber ◽  
Raw Material ◽  
Nano Particles ◽  
Molar Ratio ◽  
X Ray ◽  
Co Doping ◽  
Photocatalytic Activities ◽  
Environmental Test

In this paper, Cu-Ce/TiO2nano-particles, whose molar ratio account for 2%,2.5%,3%,3.5% and 4% respectively, were synthesized by sol-gel method, using Ti(C4H9O)4as the raw material, And the photocatalytic activities of the prepared samples were investigated by degrading formaldehyde gas under pure visible light through simulating indoor environment in the environmental test chamber. Moreover, X-Ray Powder Diffraction (XRD) and Ultraviolet-visible spectrophotometer were applied to analyze the crystallite size and optical properties of the samples. It is indicated that the sample of 2.5% performs best in the test. Besides, photocatalytic mechanism of co-doping of Cu-Ce was discussed.

Preparation of CNTs/TiO2/CS Film and its Photocatalytic Activity

2011 ◽  
Vol 287-290 ◽  
pp. 1607-1611
Author(s):  
Li Ping Zeng ◽  
Quan Zhang ◽  
Guo Qiang Zhang ◽  
Li Hui Zou
Keyword(s):  
Photocatalytic Activity ◽  
Photocatalytic Degradation ◽  
Sol Gel ◽  
Synergetic Effect ◽  
Structure And Property ◽  
Catalyst Film ◽  
Photocatalytic Activities ◽  
Ft Ir ◽  
Gaseous Formaldehyde ◽  
Carbon Nano Tube

In this work, carbon nano-tube/TiO2(CNTs/TiO2) nanocomposites were prepared using a conventional sol-gel method. To further obtain a uniform catalyst film, chitosan (CS) was used as a crosslinker for the CNTs/TiO2composite. The structure and property of CNTs/TiO2/CS film were characterized using XRD, FT-IR, TEM, SEM, and UV-vis. The photocatalytic activities of CNTs/TiO2/CS film were measured through the photocatalytic degradation of gaseous formaldehyde. Compared with the commercial TiO2, higher degradation was achieved with the CNTs/TiO2/CS film due to stronger absorbability and synergetic effect among CNTs, TiO2, and CS.

Spherical SiO2 @ GdPO4 : Eu3+ Core–Shell Phosphors: Sol–Gel Synthesis and Characterization

2007 ◽  
Vol 7 (2) ◽  
pp. 542-548 ◽  
Author(s):  
Cuikun Lin ◽  
Bo Zhao ◽  
Zhenling Wang ◽  
Min Yu ◽  
Huan Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Low Voltage ◽  
Uv Light ◽  
Sol Gel ◽  
Emission Spectra ◽  
Core Shell ◽  
Time Resolved ◽  
Potential Applications ◽  
Ft Ir ◽  
Red Luminescence

Nanocrystalline GdPO4 : Eu3+ phosphor layers were coated on non-aggregated, monodisperse and spherical SiO2 particles by Pechini sol–gel method, resulting in the formation of core–shell structured SiO2 @ GdPO4 : Eu3+ particles. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), photoluminescence (PL), low-voltage cathodoluminescence (CL), time-resolved PL spectra and lifetimes were used to characterize the core–shell structured materials. Both XRD and FT-IR results indicate that GdPO4 layers have been successfully coated on the SiO2 particles, which can be further verified by the images of FESEM and TEM. Under UV light excitation, the SiO2 @ GdPO4 : Eu3+ phosphors show orange-red luminescence with Eu3+ 5D0–7F1 (593 nm) as the most prominent group. The PL excitation and emission spectra suggest that an energy transfer occurs from Gd3+ to Eu3+ in SiO2 @ GdPO4 : Eu3+ phosphors. The obtained core–shell phosphors have potential applications in FED and PDP devices.

scholarly journals Preparation of Energetic Composites Materials via Sol-Gel

2021 ◽  
Vol 2133 (1) ◽  
pp. 012001
Author(s):  
Baoqiong Guo ◽  
Xiaoan Wei ◽  
Binbin Wang
Keyword(s):  
Composite Material ◽  
Sol Gel ◽  
Decomposition Reaction ◽  
High Energy ◽  
Time Curve ◽  
Cellulose Structure ◽  
Composites Materials ◽  
Ft Ir ◽  
Drying Technology ◽  
Energetic Composites

Abstract In this research, nitrocellulose / magnesium borohydride nanomaterials (NC / Mg(BHx)y) nanoenergetic composite materials are synthesized through sol-gel method and the freeze-drying technology. Among them, nitrocellulose (NC) is used as a gel matrix to load Mg(BHx)y particles. Scanning electron microscopy (SEM) results show that Mg(BHx)y is embedded and uniformly dispersed in the NC matrix. The particle size of the high-energy composite material is about 2 μm. The results of FT-IR showed that the hydrogen storage alloy was successfully loaded around the NC without destroying the cellulose structure. The composite material decomposition reaction (Temperature-Time) curve is obtained through the adiabatic accelerated calorimeter (ES-ARC) test.

scholarly journals Preparation of Al2O3 Bulk Aerogels by Non-supercritical Fluid Drying Technology

2005 ◽  
Vol 21 (02) ◽  
pp. 221-224 ◽  
Author(s):  
XU Zi-Jie ◽  
◽  
GAN Li-Hua ◽  
PANG Ying-Cong ◽  
CHEN Long-Wu
Keyword(s):  
Supercritical Fluid ◽  
Supercritical Fluid Drying ◽  
Drying Technology
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