Characterization of Alumina, Silica, and Titania Supported Cobalt Catalysts
TL;DR: In this paper, the structural, chemical, and electronic properties of Co catalysts supported on Al2O3, SiO2, and TiO2 as well as Co/Mn catalysts on TiO 2.
About: This article is published in Journal of Catalysis.The article was published on 2002-11-15. It has received 181 citations till now. The article focuses on the topics: Cobalt & Adsorption.
Citations
More filters
TL;DR: The as-prepared cobalt oxide (assigned as CoO x ) was fabricated by precipitation-oxidation from aqueous cobalt nitrate solution using sodium hydroxide and oxidation with hydrogen peroxide as mentioned in this paper.
707 citations
TL;DR: In this paper, the catalytic performance of Co3O4/ZSM-5 was investigated for the total oxidation of propane and their physicochemical properties were investigated by low-temperature N2 adsorption, XRD, FT-IR absorption spectroscopy, XPS, H2-TPR, TEM, and CO chemisorption.
Abstract: Co3O4 supported on ZSM-5 (Co3O4/ZSM-5) catalysts were prepared by impregnation (IM), deposition precipitation (DP), and hydrothermal (HT) methods. Their catalytic performances for the total oxidation of propane were tested, and their physicochemical properties were investigated by low-temperature N2 adsorption, XRD, FT-IR absorption spectroscopy, XPS, H2-TPR, TEM, and CO chemisorption. The results show that the catalytic activity of Co3O4/ZSM-5 for propane oxidation is higher than that of 1.5 wt % Pd/ZSM-5, and the preparation methods remarkably affect the catalytic activity of Co3O4/ZSM-5. Among four Co3O4/ZSM-5 catalysts prepared by different methods, the catalyst prepared by the HT method possesses the highest catalytic activity for propane oxidation, and their catalytic activities are varied in the order of HT > DP > IM. For the Co3O4/ZSM-5 (DP) catalysts, the precipitant has an evident influence on their catalytic activities. For instance, the DP catalyst prepared with ammonium bicarbonate precipitan...
317 citations
TL;DR: In this paper, a series of silica-supported noble and base metal catalysts prepared by strong electrostatic adsorption (SEA) was compared with the traditional incipient wetness impregnation (IWI) method.
236 citations
TL;DR: In this paper, the photocatalytic efficiency of pure or doped nanocrystalline titania was tested for discoloration of an aqueous solution of Basic Blue 41.5% for Fe3+ doping.
Abstract: Thin films of pure or doped nanocrystalline titania have been deposited on glass slides by using a sol–gel procedure, in the presence of surfactant Triton X-100, which acts as template of the nanostructure. Fe3+, Cr3+ and Co2+ were used as dopants while the doping extended in a broad domain from very low to very high levels. The photocatalytic efficiency of pure or doped titania was tested for discoloration of an aqueous solution of Basic Blue 41. The presence of dopants resulted in a progressive loss of total crystallinity, some transition from anatase into rutile and, in the case of Co2+, formation of the mixed oxide cobalt titanate. Loss of anatase had dramatic consequences on photocatalytic efficiency by UV–vis excitation, which decreased fast with increasing dopant concentration. Selected visible excitation of the doped titania could lead to photodegradation of the dye but to a far lesser degree than UV–vis excitation. Photosensitization by absorption of light by the dye itself loses its importance in the presence of the dopant. Thus the doped material is a visible-light photocatalyst but substantial photodegradation efficiency is achieved only at very high doping levels, for example, 20 at.% for Fe3+ doping. In any case, direct UV excitation of pure titania is a more efficient photocatalytic process than visible excitation of the doped semiconductor.
207 citations
TL;DR: In this article, the influence of different supports on the shape, appearance, and size of cobalt particles, as well as on reducibility, was studied by different techniques, including X-ray diffraction, scanning transmission electron microscopy, H2 chemisorption, N2 adsorption measurements, temperature-programmed reduction, and O2 titration.
199 citations
References
More filters
24,580 citations
Book•
12 Oct 1992
TL;DR: In this paper, the authors used the carbon C 1s peak at 285 eV as a reference for charge correction in XPS analyses of samples prepared outside the high vacuum chamber relatively thick carbon layers are formed on the surfaces.
Abstract: Analysis of XPS spectra of Fe2 and Fe3 ions in oxide April 15th, 2019 Carbon is ubiquitous and is present on all surfaces for XPS analysis It is common practice to use the carbon C 1s peak at 285 eV as a reference for charge correction In routine XPS analyses of samples prepared outside the high vacuum chamber relatively thick carbon layers are formed on the surfaces and the corrected XPS peak positions are independent of the apparent or experimentally
3,450 citations
2,538 citations
Book•
01 Jan 1984
TL;DR: In this paper, the authors present a detailed description of the properties of solid state chemistry, including point groups, space groups, and crystal structure, as well as some factors which influence crystal structure.
Abstract: What is Solid State Chemistry? Preparative Methods. Characterization of Inorganic Solids: Application of Physical Techniques. Thermal Analysis. X-ray Diffraction. Point Groups, Space Groups and Crystal Structure. Descriptive Crystal Chemistry. Some Factors Which Influence Crystal Structure. Crystal Defects and Non-Stoichiometry. Solid Solutions. Interpretation of Phase Diagrams. Phase Transitions. Ionic Conductivity and Solid Electrolytes. Electronic Properties and Band Theory: Metals, Semiconductors, Inorganic Solids, Colour. Other Electrical Properties. Magnetic Properties. Optical Properties: Luminescence, Lasers. Glass. Cement and Concrete. Refractories. Organic Solid State Chemistry. Appendixes. Index.
2,106 citations
TL;DR: In this article, toluene-solvated cobalt atoms nucleate at surface OH groups, and the resultant cobalt oxide surface species serve as sites for nucleation of more cobalt atom, leading to very small, reactive metallic clusters.
Abstract: XPS studies of solvated metal atom dispersed (SMAD) catalysts coupled with detailed studies of reference compounds were carried out. It was shown that toluene-solvated cobalt atoms nucleate at surface OH groups, and the resultant cobalt oxide surface species serve as sites for nucleation of more cobalt atoms, leading to very small, reactive metallic clusters. The surface of these clusters/particles are partially oxidized by adventitious oxygen or water, but when cobalt loadings of over 4% are used, a major portion of the catalytic particle remains metallic. When solvated cobalt and manganese atoms are mixed together, the manganese atoms deposit first at surface OH sites, and manganese is highly dispersed in this way, but the majority ends up as surface MnO and Mn 2 O 3
904 citations