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1.
Anton Purnomo Susan Gallardo Leonila Abella Chris Salim Hirofumi Hinode 《Reaction Kinetics and Catalysis Letters》2008,95(2):213-220
The characterization and catalytic activity of a Ni/CeO2/ZrO2 catalyst for methane steam reforming at 600°C were investigated. The addition of ceria increased the surface area and basicity
of the catalysts. The redox reaction capability of the ceria increased the hydrogen yield and carbon monoxide selectivity,
and inhibited carbon formation. 相似文献
2.
The formation of hollow binary ZrO2/TiO2 oxide fibers using mixed precursor solutions was achieved by activated carbon fibers templating technique combined with solvothermal process. The samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), N2 adsorption, X-ray photoelectron spectroscopy (XPS), UV-vis, and infrared (IR) spectroscopy. The binary oxide system shows the anatase-type TiO2 and tetragonal phase of ZrO2, and the introduction of ZrO2 notably inhibits the growth of TiO2 nanocrystallites. Although calcined at 575 °C, all hollow ZrO2/TiO2 fibers exhibit higher surface areas (>113 m2/g) than pure TiO2 hollow fibers. The Pyridine adsorption on ZrO2/TiO2 sample indicates the presence of stronger surface acid sites. Such properties bring about that the binary oxide system possesses higher efficiency and durable activity stability for photodegradation of gaseous ethylene and trichloromethane than P25 TiO2. In addition, the macroscopic felt form for the resulting materials is more beneficial for practical applications than traditional catalysts forms. 相似文献
3.
TiO2 nanoparticles incorporated with CuInS2 clusters were prepared in a solvothermal process and characterized with X-ray diffraction (XRD), transmission electron microscopy (TEM), and energy-dispersion X-ray analysis (EDX). Compared with pure TiO2 nanoparticles, the TiO2 nanoparticles incorporated with CuInS2 clusters display higher photocatalytic activity with 99.9% of degradation ratio of 4-nitrophenol after 2 h irradiation. In order to investigate the effect of the CuInS2 clusters on the photocatalytic activity of TiO2 nanoparticles, diffuse reflectance UV–Vis spectra (DRS), photoluminescence (PL) spectra, and photocurrent action spectra were measured. The results indicate that the enhanced photocatalytic activity is probably due to the interface between TiO2 and CuInS2 as a trap of the photogenerated electrons to decrease the recombination of electrons and holes. 相似文献
4.
ZnO/TiO2/SnO2 mixture was prepared by mixing its component solid oxides ZnO, TiO2 and SnO2 in the molar ratio of 4?1?1, followed by calcining the solid mixture at 200-1300 °C. The products and solid-state reaction process during the calcinations were characterized with powder X-ray diffraction (XRD), thermogravimetric and differential thermal analysis (TG-DTA), UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS) and Brunauer-Emmett-Teller measurement of specific surface area. Neither solid-state reaction nor change of crystal phase composition took place among the ZnO, TiO2 and SnO2 powders on the calcinations up to 600 °C. However, formation of the inverse spinel Zn2TiO4 and Zn2SnO4 was detected at 700-900 and 1100-1200 °C, respectively. Further increase of the calcination temperature enabled the mixture to form a single-phase solid solution Zn2Ti0.5Sn0.5O4 with an inverse spinel structure in the space group of . The ZnO/TiO2/SnO2 mixture was photocatalytically active for the degradation of methyl orange in water; its photocatalytic mass activity was 16.4 times that of SnO2, 2.0 times that of TiO2, and 0.92 times that of ZnO after calcination at 500 °C for 2 h. But, the mass activity of the mixture decreased with increasing the calcination temperature at above 700 °C because of the formation of the photoinactive Zn2TiO4, Zn2SnO4 and Zn2Ti0.5Sn0.5O4. The sample became completely inert for the photocatalysis after prolonged calcination at 1300 °C (42 h), since all of the active component oxides were reacted to form the solid solution Zn2Ti0.5Sn0.5O4 with no photocatalytic activity. 相似文献
5.
甲烷在Ni/TiO2催化剂表面的活化 总被引:2,自引:0,他引:2
考察了Ni/TiO2催化剂甲烷部分氧化和二氧化碳重整制合成气的反应活性,实验表明,以TiO2为载体的镍系催化剂对于甲烷部分氧化制合成气反应具有较好的活性,尤其对H2的选择性较高,对二氧化碳重整制合成气反应具有较好的低温反应活性.采用脉冲-质谱在线分析等技术,在无气相氧条件下向Ni/TiO2催化剂脉冲CH4,发现甲烷在催化剂表面的活化(转化)及其氧化产物的选择性与金属催化剂表面氧的浓度密切相关.CH4与Ni/TiO2催化剂作用过程中存在明显的氢溢流和氧溢流现象,可能是这种溢流效应使得Ni/TiO2催化剂具有良好的反应活性和抗积碳性能. 相似文献
6.
Xinsheng Li Jong-San Chang Sang-Eon Park 《Reaction Kinetics and Catalysis Letters》1999,67(2):375-381
CO2 reforming of methane is performed over zirconia-supported nickel catalysts. The catalysts show high activity toward CH4 and CO2 conversions. Over the high Ni loading catalyst, long-term performances without significant deactivations have been achieved
at 1023 K for 30 h and 1123 K for 20 h, respectively. The effects of reduction and calcination temperatures on the catalytic
activities are also examined. 相似文献
7.
以硝酸银、钛酸四丁酯、无水氯化锌、六水氯化铁为原料,采用溶胶-凝胶法与溶剂热相结合的方法制备了ZnFe2O4/Ag/TiO2复合材料,通过扫描电子显微镜、能谱分析仪、X射线粉末衍射仪、X射线光电子能谱仪、振动样品磁强计、紫外可见分光光度计对样品进行表征及测试。结果表明: ZnFe2O4/Ag/TiO2-10具有最佳的光催化效果,在紫外和可见光下对染料的降解率都能达到90%以上,具有优异的紫外可见光光催化活性。ZnFe2O4/Ag/TiO2具有独特的磁性,能在外部磁场作用下进行回收利用,这使其在实际应用中成为可能。通过磁分离技术重复回收利用5次后仍然保持优良的光催化性能,说明ZnFe2O4/Ag/TiO2-10具有优异的磁性及较高的光催化循环稳定性。 相似文献
8.
以硝酸银、钛酸四丁酯、无水氯化锌、六水氯化铁为原料,采用溶胶-凝胶法与溶剂热相结合的方法制备了ZnFe2O4/Ag/TiO2复合材料,通过扫描电子显微镜、能谱分析仪、X射线粉末衍射仪、X射线光电子能谱仪、振动样品磁强计、紫外可见分光光度计对样品进行表征及测试。结果表明:ZnFe2O4/Ag/TiO2-10具有最佳的光催化效果,在紫外和可见光下对染料的降解率都能达到90%以上,具有优异的紫外可见光光催化活性。ZnFe2O4/Ag/TiO2具有独特的磁性,能在外部磁场作用下进行回收利用,这使其在实际应用中成为可能。通过磁分离技术重复回收利用5次后仍然保持优良的光催化性能,说明ZnFe2O4/Ag/TiO2-10具有优异的磁性及较高的光催化循环稳定性。 相似文献
9.
Jing Liqiang Sun Xiaojun Xin Baifu Cai Weimin 《Journal of solid state chemistry》2004,177(10):3375-3382
In this paper, pure and La doped TiO2 nanoparticles with different La content were prepared by a sol-gel process using Ti (OC4H9)4 as raw material, and also were characterized by XRD, TG-DTA, TEM, XPS, DRS and Photoluminescence (PL) spectra. We mainly investigated the effects of calcining temperature and La content on the properties and the photocatalytic activity for degrading phenol of as-prepared TiO2 samples, and also discussed the relationships between PL spectra and photocatalytic activity as well as the mechanisms of La doping on TiO2 phase transformation. The results showed that La3+ did not enter into the crystal lattices of TiO2 and was uniformly dispersed onto TiO2 as the form of La2O3 particles with small size, which possibly made La dopant have a great inhibition on TiO2 phase transformation; La dopant did not give rise to a new PL signal, but it could improve the intensity of PL spectra with a appropriate La content, which was possibly attributed to the increase in the content of surface oxygen vacancies and defects after doping La; La doped TiO2 nanoparticles calcined at 600°C exhibited higher photocatalytic activity, indicating that 600°C was an appropriate calcination temperature. The order of photocatalytic activity of La doped TiO2 samples with different La content was as following: 1>1.5>3>0.5>5>0 mol%, which was the same as the order of their PL intensity, namely, the stronger the PL intensity, the higher the photocatalytic activity, demonstrating that there were certain relationships between PL spectra and photocatalytic activity. This could be explained by the points that PL spectra mainly resulted from surface oxygen vacancies and defects during the process of PL, while surface oxygen vacancies and defects could be favorable in capturing the photoinduced electrons during the process of photocatalytic reactions. 相似文献
10.
Sb2S3/Bi2S3 doped TiO2 were prepared with the coordination compounds [M(S2CNEt)3] (M=Sb, Bi; S2CNEt=pyrrolidinedithiocarbamate) as precursors via gel-hydrothermal techniques. The doped TiO2 were characterized by XRD, SEM, XPS and UV-vis diffuse reflectance means. The photocatalyst based on doped TiO2 for photodecolorization of 4-nitrophenol (4-NP) was examined. The optimal Bi2S3/Sb2S3 content, pH and different doped techniques have been investigated. Photocatalytic tests reveal that M2S3 doped TiO2 via the gel-hydrothermal route performs better photocatalytic activity for photodegradation reaction of 4-nitrophenol (4-NP). 相似文献
11.
Jun Yang Liwei Zhu Jun Zhang Yuanming Zhang Yu Tang 《Reaction Kinetics and Catalysis Letters》2007,91(1):21-28
Nanosized TiO2/SiO2 catalysts prepared by hydrolysis of titanium n-butoxide in microemulsion showed enhanced photocatalytic activity. In the presence of catalyst ME-2 and after 90 min irradiation
by UV light, methylene blue was completely converted evidenced by the absence of its absorption band in the UV-Vis spectra.
This catalyst demonstrated much better degradation ability than P-25 and naked TiO2. 相似文献
12.
Marianna Kemell Elina Färm Mikko Ritala Markku Leskelä 《European Polymer Journal》2008,44(11):3564-3570
Al2O3 and TiO2 thin films were deposited by atomic layer deposition at 80-250 °C on various polymeric substrates such as polymethylmethacrylate (PMMA), polyetheretherketone (PEEK), polytetrafluoroethylene (PTFE) and ethylenetetrafluoroethylene (ETFE). The films were studied with FESEM, EDX, XRD, contact angle measurements and adhesion tests. The film growth rates on the thermoplastics were close to the corresponding growth rates on Si substrates. The adhesion of the films was good on PEEK and poor on PTFE. All coated surfaces showed lower water contact angles than the uncoated thermoplastics. Furthermore, the water contact angles on all TiO2-coated surfaces decreased upon UV illumination, most efficiently with crystalline TiO2 coatings. 相似文献
13.
L. Reijnders 《Polymer Degradation and Stability》2009,94(5):873-876
There is a growing interest in the development of nanocomposites consisting of organic polymers and TiO2 or amorphous SiO2 nanoparticles. These nanoparticles may be released from nanocomposites. There is evidence that amorphous SiO2 and TiO2 nanoparticles can be hazardous. Thus, in the design of nanocomposites with such nanoparticles, hazard reduction extending to the full nanocomposite life cycle would seem a matter to consider. Options for hazard reduction include: changes of nanoparticle surface, structure or composition, better fixation of nanoparticles in nanocomposites, including persistent suppression of oxidative damage to polymers by nanoparticles, and design changes leading to the release of relatively large particles. 相似文献
14.
CoFe2O4/TiO2 magnetic composite films were prepared using the sol-gel method with tetrabutyltitanate and metallic chlorates as starting
materials. The effects of heat treatment temperatures on microstructures and on magnetic properties were studied. The microstructure
and properties of the samples at different heat treatment temperatures were characterized by X-ray diffraction, Raman spectrum,
scanning electron microscopy, polarized microscopy and vibrating sample magnetometry. The results show that crystals of different
substances grow up independently. Cobalt ferrite is evenly embedded into the titanium dioxide matrix in the prepared composite
films. The magnetism of the composite films is enhanced with an increase of the heat temperature.
Supported by the National Natural Science Foundation of China (Grant Nos. 50632030 and 10474077), and the Natural Science
Foundation of Shaanxi Province (Grant No. 2006E135) 相似文献
15.
Catalytic oxidation of no to NO2 over Cr/TiO2 and Cu/TiO2 under oxidizing atmosphere 总被引:1,自引:0,他引:1
The catalytic activity of Cr/TiO2 and Cu/TiO2 for the oxidation of NO under an oxidizing atmosphere has been examined. Both catalysts had excellent ability for the oxidation of NO to NO2 in the temperature range of 350–400°C. 相似文献
16.
以锐钛矿相TiO2溶胶为基底,采用沉淀法和液相沉积法制备了TiO2/Cu2O/Pt复合空心微球,通过改变nTi4+∶ nCu2+和H2PtCl6·6 H2O溶液的加入量对TiO2的形貌和结构进行调控,采用不同的方法对不同样品的物相及结构、微观形貌和光学性能进行了对比分析。分析结果表明,复合材料中Pt与Cu2O的引入产生协同效应,不仅在一定程度上阻止了电子-空穴的复合,还降低了禁带宽度,在可见光区域光吸收明显增强。与TiO2、Cu2O和TiO2/Cu2O光催化剂相比较,TiO2/Cu2O/Pt降解有机污染物的能力显著增强,首次光照120 min可降解93%的甲基橙(MO)溶液,4次循环后降解率为71%,具有良好的光催化稳定性能。 相似文献
17.
以锐钛矿相TiO2溶胶为基底,采用沉淀法和液相沉积法制备了TiO2/Cu2O/Pt复合空心微球,通过改变n(Ti4+)∶nCu2+和H2Pt Cl6·6H2O溶液的加入量对TiO2的形貌和结构进行调控,采用不同的方法对不同样品的物相及结构、微观形貌和光学性能进行了对比分析。分析结果表明,复合材料中Pt与Cu2O的引入产生协同效应,不仅在一定程度上阻止了电子-空穴的复合,还降低了禁带宽度,在可见光区域光吸收明显增强。与TiO2、Cu2O和TiO2/Cu2O光催化剂相比较,TiO2/Cu2O/Pt降解有机污染物的能力显著增强,首次光照120 min可降解93%的甲基橙(MO)溶液,4次循环后降解率为71%,具有良好的光催化... 相似文献
18.
Pei Fung Lee Xiwang Zhang Darren D. Sun Jianhong Du James O. Leckie 《Colloids and surfaces. A, Physicochemical and engineering aspects》2008,324(1-3):202-207
In this work bimodal structured titanium dioxide (TiO2) microsphere has been prepared from commercial TiO2 powder and nano-sized titania gel via sol–gel spray-coating technique. Crystallization and transformation behavior of titania gel were investigated. The results revealed that the crystallization and transformation of anatase particles were substantially affected by the concentration of solvent and calcination temperature. Anatase crystallite size of 10 nm was obtained at mole ratio of solvent/precursor 50/1 and calcination temperature of 450 °C. The prepared nano-sized titania gel was embedded within the core (commercial TiO2, P25) during the spraying process. The prepared TiO2 microsphere was characterized using X-ray diffractometer (XRD), scanning electron microscope (SEM), field emission electron microscope (FESEM) and micropore analysis. The photocatalytic activity was monitored by following the degradation of phenol with activity benchmarked against commercial P25 (Degussa). The increase of photocatalytic activity of TiO2 microsphere was attributed to the nano-sized anatase crystallite which has been incorporated into the TiO2 microsphere. 相似文献
19.
Photocatalytic activities of anodized TiO2 films for decomposition of gaseous acetaldehyde were investigated. The anodized TiO2 films were fabricated by galvanostatic anodization in a mixed electrolyte composed of H2SO4, H3PO4, and H2O2. Pre-nitridation treatment effectively enhanced the photocatalytic activity of the anodized TiO2 films. The electrolysis parameters such as anodization time, current density, electrolyte temperature, and electrolyte composition significantly affected the photocatalytic activity of the anodized TiO2 films. The improvement of photocatalytic activity of the anodized films is attributed to increase in surface areas of the anodized specimens. 相似文献
20.
H2 with low CO concentration is produced via photocatalytic reforming of glucose (as a representative of biomass component)
on metal/TiO2 catalyst (metals: Pt, Rh, Ru, Ir, Au, Ni, Cu). It is shown that the loaded metals generally enhance the rate of H2 production, while they depress the CO selectivity. Both H2 production and CO selectivity are strongly dependent on the kind of deposited metals on TiO2. For example, Rh/TiO2 catalyst is found to be most active for H2 production while with the most extremely low CO concentration from the photocatalytic reforming of glucose.
Supported by the National Natural Science Foundation of China (Grant No. 20403018, 20503034), National Basic Research Program
of China (Grant No. 2003CB214504), and Knowledge Innovation Program of the Chinese Academy of Sciences (DICP K2006E2) 相似文献