scholarly journals Catalytic Oxidation of Toluene Over LaNixB1-xO3 (B=Co, Cu) Perovskite Catalysts

2021 ◽  
Author(s):  
Songya Qi ◽  
Wanqi Zhang ◽  
Xiang Li ◽  
Qing Wang ◽  
Zerui Zhu ◽  
...  
Keyword(s):  
Sol Gel ◽  
Molar Ratio ◽  
Toluene Degradation ◽  
Co Doping ◽  
Calcination Temperatures ◽  
Structure Morphology ◽  
Volatile Organic ◽  
Volatile Organic Pollutants ◽  
Perovskite Catalysts ◽  
Short Time

Abstract A series of LaNixB1-xO3 (B=Co, Cu) perovskite catalysts were prepared by sol-gel method and employed in toluene degradation. The catalysts were characterized by XRD, UV-Vis, SEM and XPS to investigate crystal structure, morphology and composition of the catalyst. The effect of different calcination temperatures and time on the performance of perovskite catalysts for toluene degradation were investigated. And the CO2 selectivity was also carried out on as-prepared catalysts. The results showed that a small amount of Co-doping in B site of LaNiO3 could significantly improve its toluene degradation, while the substitution of Ni with Cu could not effectively enhance its activity. When the Ni/Co molar ratio in LaNixCo1-xO3 perovskite was 3:1, LaNi0.75Co0.25O3 catalyst exhibited the best activity, and it showed relatively short time and low temperature for toluene conversion of 100%. Therefore, LaNi0.75Co0.25O3 catalyst has a broad prospect in the degradation of volatile organic pollutants.

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.

scholarly journals Photocatalytic Improvement under Visible Light inTiO2Nanoparticles by Carbon Nanotube Incorporation

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Mathana Wongaree ◽  
Siriluk Chiarakorn ◽  
Surawut Chuangchote
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Sol Gel ◽  
Multiwall Carbon Nanotubes ◽  
High Specific Surface Area ◽  
Molar Ratio ◽  
Molar Ratios ◽  
Calcination Temperatures ◽  
Photocatalytic Activities ◽  
Multiwall Carbon

Photocatalytic activity ofTiO2nanoparticles was successfully enhanced by addition of multiwall carbon nanotubes (MWCNT) to make CNT/TiO2nanocomposites by sol-gel method at ambient temperature. CNT treated by HNO3 : H2SO4treatment (1 : 3 v/v) was mixed withTiO2nanoparticles at various molar ratios and calcination temperatures. The optimal molar ratio of CNT : TiO2was found at 0.05 : 1 by weight. The optimal calcination condition was 400°C for 3 h. From the results, the photocatalytic activities of CNT/TiO2nanocomposites were determined by the decolorization of 1 × 10−5 M methylene blue (MB) under visible light. CNT/TiO2nanocomposites could enhance the photocatalytic activity and showed faster for the degradation of MB with only 90 min. The degradation efficiency of the MB solution with CNT/TiO2nanocomposite achieved 70% which was higher than that with pristineTiO2(22%). This could be explained that CNT preventsTiO2from its agglomeration which could further enhance electron transfer in the composites. In addition, CNT/TiO2nanocomposites had high specific surface area (202 m2/g) which is very promising for utilization as a photocatalyst for environmental applications.

Preparation of Nd and Co Co-Doped BiFeO3 Thin Films Co-Doping Nd and Co by Sol-Gel Method

2012 ◽  
Vol 512-515 ◽  
pp. 1249-1252 ◽  
Author(s):  
Xu Xue ◽  
Guo Qiang Tan ◽  
Hui Jun Ren ◽  
Meng Cheng
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Dielectric Loss ◽  
Raw Materials ◽  
Sol Gel ◽  
Gel Method ◽  
Sol Gel Method ◽  
Co Doping ◽  
Structure Morphology ◽  
Lcr Meter

BiFeO3 thin films co-doping Nd and Co were prepared on FTO/glass substrate by sol-gel method with Bi(NO3)3•5H2O, Fe•(NO3)3•9H2O, Nd(NO3)3•6H2O and Co(NO3)2•6H2O as raw materials, 2-methoxyethanol together with acetic anhydride as a solvent. XRD, FE-SEM, Agilent E4980A Precision LCR Meter and TF 2000 Ferroelectric Analyzer were used to characterize the structure, morphology, dielectric property and ferroelectric property of the BiFeO3 thin films. The results show that after Nd and Co co-doping, the BiFeO3 thin films still keep the perovskite structure. The crystal structure turns square or orthogonal from rhombus. The thickness of the BiFeO3 thin films is about 500nm and the grain size is 80nm to 30nm. BiFeO3 thin films co-doping Nd and Co have the larger dielectric constant and the lower dielectric loss compared with Nd doping. BiFeO3 thin films co-doping Nd10% and Co1% have the dielectric constant of over 170 and the dielectric loss of below 0.03. Both have the better frequency stability. Co-doping Nd and Co could decrease the coercive electric field of BiFeO3 thin films.

Preparation and Evaluation of Fe2O3/Ceramic Composites for Flue Gas Desulfurization

2011 ◽  
Vol 117-119 ◽  
pp. 1410-1413
Author(s):  
Xin Min ◽  
Jun Jie Bian ◽  
Shu Zhang ◽  
Chun Hu Li ◽  
Li Juan Feng
Keyword(s):  
Removal Efficiency ◽  
Flue Gas ◽  
Ferric Oxide ◽  
Sol Gel ◽  
Ceramic Composites ◽  
Ceramic Surface ◽  
Sem Images ◽  
Calcination Temperatures ◽  
Structure Morphology ◽  
Oxide Composites

Ceramic supported ferric oxide composites were synthesized by impregnation- precipitation (I) and sol-gel (II) methods using FeSO4as a precursor. We investigated the effect of the calcination temperatures on the structure, morphology, and agglomeration of supported ferric oxide. It has been found that Fe2O3was stabilized when the as-synthesized composites were calcinated at 330-360 °C under 10% (v/v) O2/N2mixture, and the calcination temperature was chosen as 350°C . The SEM images demonstrated that for the composite I, which was prepared by method (I), Fe2O3 nanoparticles were distributed on the surface and pores of the ceramic; while for the composite II, which was synthesized by method (II), Fe2O3thin layer was covered the surface of the ceramic. EDS analysis showed 7.9% (wt) ferric oxide had been supported on the composite I and up to 13.3% (wt) ferric oxide on the composite II. XPS analysis revealed that the valence of iron was +3 on both composites. Fe2O3/ceramic composites were used as the catalysts for low temperature wet Flue Gas Desulphurization (FGD), and demonstrated higher SO2removal efficiency. Because of the excellent hydrophilicity of ceramic and high dispersibility of Fe2O3 on ceramic surface, this catalyst had high SO2removal efficiency at 60°C even at pH2O3/ceramic composites, prepared by a simple, reproducible impregnation-precipitation and sol-gel method, was an inexpensive, active catalyst for S(IV) catalytic oxidation in wet FGD process in an economical feasible temperature range.

scholarly journals Enhancing the photoactivity of TiO2/SiO2 monolithic catalyst and its reusability for wastewater treatment

2019 ◽  
Vol 268 ◽  
pp. 07005
Author(s):  
Ngoc Diem Trinh Huynh ◽  
Kieu Duyen Vo ◽  
Thao Vy Nguyen ◽  
Minh Vien Le
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Sol Gel ◽  
Dip Coating ◽  
Molar Ratio ◽  
Coating Process ◽  
Visible Light Region ◽  
Molar Ratios ◽  
Calcination Temperatures ◽  
Light Region

A series of TiO2/SiO2 photocatalysts were successfully synthesized by the sol-gel method. The TiO2/SiO2 monolith was also synthesized by dip-coating process. The crystalline structure of TiO2/SiO2 powders was identified as pure anatase. The photocatalytic activity of the TiO2/SiO2 powders was evaluated by photodegradation of 20 ppm methylene blue (MB) using a 26W lamp which has the wavelength in the visible light region under different Ti: Si molar ratios and calcination temperatures. The TiO2/SiO2 powders which have Ti: Si molar ratio of 85:15 (TS15) and calcined at 550tC showed the highest photodegradation yield of 84 % after 3h irradiation. Furthermore, the 550˚C calcined TS15 monolith performed the MB degradation yield of 88.9 % after 3h irradiation and its photoactivity still remained after 4 recycle times. The results of this study demonstrated that the TS15 monolith photocatalyst has a reasonable efficiency in the degradation of methylene blue, it could be a promising photocatalyst for removal and degradation of organic pollutants.

scholarly journals Sol-Gel Synthesis, Structure, Morphology and Magnetic Properties of Ni0.6Mn0.4Fe2O4 Nanoparticles Embedded in SiO2 Matrix

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3455
Author(s):  
Thomas Dippong ◽  
Erika Andrea Levei ◽  
Iosif Grigore Deac ◽  
Ioan Petean ◽  
Gheorghe Borodi ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Sol Gel ◽  
Average Crystallite Size ◽  
Secondary Phase ◽  
Ferromagnetic Behavior ◽  
Sio2 Matrix ◽  
Calcination Temperatures ◽  
Structure Morphology ◽  
A Minor ◽  
Sol Gel Synthesis

The structure, morphology and magnetic properties of (Ni0.6Mn0.4Fe2O4)α(SiO2)100−α (α = 0–100%) nanocomposites (NCs) produced by sol-gel synthesis were investigated using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), atomic force microscopy (AFM) and vibrating sample magnetometry (VSM). At low calcination temperatures (300 °C), poorly crystallized Ni0.6Mn0.4Fe2O4, while at high calcination temperatures, well-crystallized Ni0.6Mn0.4Fe2O4 was obtained along with α-Fe2O3, quartz, cristobalite or iron silicate secondary phase, depending on the Ni0.6Mn0.4Fe2O4 content in the NCs. The average crystallite size increases from 2.6 to 74.5 nm with the increase of calcination temperature and ferrite content embedded in the SiO2 matrix. The saturation magnetization (Ms) enhances from 2.5 to 80.5 emu/g, the remanent magnetization (MR) from 0.68 to 12.6 emu/g and the coercive field (HC) from 126 to 260 Oe with increasing of Ni0.6Mn0.4Fe2O4 content in the NCs. The SiO2 matrix has a diamagnetic behavior with a minor ferromagnetic fraction, Ni0.6Mn0.4Fe2O4 embedded in SiO2 matrix displays superparamagnetic behavior, while unembedded Ni0.6Mn0.4Fe2O4 has a high-quality ferromagnetic behavior.

scholarly journals Structural and Photoluminescence Investigations of Tb3+/Eu3+ Co-Doped Silicate Sol-Gel Glass-Ceramics Containing CaF2 Nanocrystals

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 754
Author(s):  
Natalia Pawlik ◽  
Barbara Szpikowska-Sroka ◽  
Tomasz Goryczka ◽  
Joanna Pisarska ◽  
Wojciech A. Pisarski
Keyword(s):  
Sol Gel ◽  
Glass Ceramics ◽  
Emission Spectra ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Co Doping ◽  
Near Ultraviolet ◽  
Transmission Electron ◽  
Co Doped

In this work, the series of Tb3+/Eu3+ co-doped xerogels and derivative glass-ceramics containing CaF2 nanocrystals were prepared and characterized. The in situ formation of fluoride crystals was verified by an X-ray diffraction technique (XRD) and transmission electron microscopy (TEM). The studies of the Tb3+/Eu3+ energy transfer (ET) process were performed based on excitation and emission spectra along with luminescence decay analysis. According to emission spectra recorded under near-ultraviolet (NUV) excitation (351 nm, 7F6 → 5L9 transition of Tb3+), the mutual coexistence of the 5D4 → 7FJ (J = 6–3) (Tb3+) and the 5D0 → 7FJ (J = 0–4) (Eu3+) luminescence bands was clearly observed. The co-doping also resulted in gradual shortening of a lifetime from the 5D4 state of Tb3+ ions, and the ET efficiencies were varied from ηET = 11.9% (Tb3+:Eu3+ = 1:0.5) to ηET = 22.9% (Tb3+:Eu3+ = 1:2) for xerogels, and from ηET = 25.7% (Tb3+:Eu3+ = 1:0.5) up to ηET = 67.4% (Tb3+:Eu3+ = 1:2) for glass-ceramics. Performed decay analysis from the 5D0 (Eu3+) and the 5D4 (Tb3+) state revealed a correlation with the change in Tb3+–Eu3+ and Eu3+–Eu3+ interionic distances resulting from both the variable Tb3+:Eu3+ molar ratio and their partial segregation in CaF2 nanophase.

scholarly journals Role of CA-EDTA on the Synthesizing Process of Cerate-Zirconate Ceramics Electrolyte

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Nur Athirah Abdullah ◽  
Sharizal Hasan ◽  
Nafisah Osman
Keyword(s):  
Thermal Decomposition ◽  
Citric Acid ◽  
Chelating Agents ◽  
Sol Gel ◽  
Decomposition Temperature ◽  
Metal Nitrate ◽  
Molar Ratio ◽  
Calcination Temperatures ◽  
Decomposition Behaviour

The role of a combination between citric acid (CA) and ethylenediaminetetra acetic acid (EDTA) as chelating agents in preparation of BaCe0.54Zr0.36Y0.1O2.95powder by a modified sol-gel method is reported. The precursor solutions were prepared from metal nitrate salts (M+), chelating agents (C), and ethylene glycol (EG) at molar ratio of M+ : C : EG = 3 : 2 : 3. Chemical and phase transformation of samples during thermal decomposition were analyzed by thermogravimetric analysis (TGA) and Fourier transform infrared (FTIR) spectroscopy. TGA results show that the sample prepared by a combination of CA-EDTA exhibited the lowest thermal decomposition temperature,Ttdsince there was no significant weight loss after 750°C. After calcined at 1100°C, the carbonates residue remained in the samples as proven by FTIR results. It was found that the used combination of CA-EDTA acts as a better combustion reagent to increase the reaction rate and influence the thermal decomposition behaviour compared to a single citric acid and EDTA, respectively. Apparently, calcination temperatures above 1100°C are needed to produce a pure perovskitic BaCe0.54Zr0.36Y0.1O2.95.

Magnetic Composite Fe3O4/CuO/TiO2 Nanoparticles: Preparation, Characterization and Photocatalytic Activity

2015 ◽  
Vol 827 ◽  
pp. 13-18 ◽  
Author(s):  
Shofianina Jalaludin ◽  
Sarah A. Arifin ◽  
Rosari Saleh
Keyword(s):  
Methylene Blue ◽  
Degradation Rate ◽  
Photocatalytic Performance ◽  
Sol Gel ◽  
Cuo Nanoparticles ◽  
Composite Nanoparticles ◽  
Molar Ratio ◽  
Magnetic Composite ◽  
Photocatalytic Efficiency ◽  
Structure Morphology

Magnetic composite Fe3O4/TiO2/CuO nanoparticles have been synthesized by sol-gel method at low temperature. The resultant composite nanoparticles coupled with different Cu contained by adjusting the molar ratio of CuO to (Fe3O4/TiO2) from 1:1 – 5:1. The structure, morphology and properties of nanoparticles were characterized using XRD, EDX, FESEM and VSM. The results showed that all composite nanoparticles consist of cubic spinel Fe3O4, anatase TiO2 and monoclinic CuO, have ferromagnetic properties. The photocatalytic performance was evaluated using methylene blue in aqueous solutions under UV and visible light irradiation. Among the composite Fe3O4/TiO2/CuO nanoparticles, the sample with the molar ratio of CuO to (Fe3O4/TiO2) = 5 : 1 exhibited the highest photocatalytic efficiency. Photocatalytic mechanism was investigated by measuring the photocatalytic degradation rate in the presence of scavenger. The results suggested that holes play the most important role in degradation of methylene blue.

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