排序方式: 共有47条查询结果,搜索用时 15 毫秒
41.
Christoffel Vansant Herman O. Desseyn Spyros P. Perlepes 《Transition Metal Chemistry》1995,20(5):454-459
Summary The preparation of oxamic acid complexes of general formula M(H2NCOCOO)2·xH2O (M = MnII, CoII, NiII, CuII or ZnII; x = 1 for CuII, x = 2 for the other metals) is reported. The i.r. and Raman spectra are discussed considering a trans-octahedral structure, formed by five-membered chelate rings with the amide oxygen and one carboxylic oxygen as donor atoms. The apical positions are occupied by water molecules. The thermal degradation process is very similar for the different complexes, first losing H2O in one or different steps, then the fragments of the organic ligand to give the metal oxide as residue. The thermal degradation of the CuII and ZnII compounds results in the formation of a new polymeric compound by deprotonation of the primary amide function in an endothermic process, the polymer further decomposes to form the metal oxide. 相似文献
42.
Gkika D. A. Vordos N. Nolan J. W. Mitropoulos A. C. Vansant E.F. Cool P. Braet J. 《Journal of nanoparticle research》2017,19(5):1-11
Journal of Nanoparticle Research - Functionalised electrospun polyamide-6 (PA-6) nanofibres incorporating gadolinium oxide nanoparticles conjugated to zinc tetracarboxyphenoxy phthalocyanine... 相似文献
43.
Van der Voort P Ravikovitch PI De Jong KP Neimark AV Janssen AH Benjelloun M Van Bavel E Cool P Weckhuysen BM Vansant EF 《Chemical communications (Cambridge, England)》2002,(9):1010-1011
We describe in this paper the development of plugged hexagonal templated silicas (PHTS) which are hexagonally ordered materials, with internal microporous silica nanocapsules; they have a combined micro- and mesoporosity and a tuneable amount of both open and encapsulated mesopores and are much more stable than other tested micellar templated structures. 相似文献
44.
Kuśtrowski P Chmielarz L Dziembaj R Cool P Vansant EF 《The journal of physical chemistry. B》2005,109(23):11552-11558
Four various mesoporous silicas (MCM-48, SBA-15, MCF, and MSU) were modified by the molecular designed dispersion method using Fe(acac)3, Cr(acac)3, and Cu(acac)2 complexes. The deposition was performed at the same concentration of the metal acetylacetonate (acac) complex in a toluene solution. All as-synthesized samples were investigated by diffuse reflectance infrared Fourier transform spectroscopy, Fourier transform infrared photoacoustic spectroscopy, and thermogravimetric analysis. The calcined materials were studied with respect to their textural properties (Brunauer-Emmett-Teller adsorption isotherm) and chemical composition (electron microprobe analysis). It allowed elucidation of the mechanism of interaction between the acac complex and the silanol groups. For the MCM-48, SBA-15, and MCF materials, the formation of hydrogen bonding was found for the chromium- and copper-modified samples, whereas the Fe-containing materials showed the ligand exchange mechanism. The strong interaction of the MSU support and the different acetylacetonate complexes, resulting in a loss of at least one acac ligand, was observed. The mesoporous silicas modified with transition metal oxides were studied by UV-vis-DR spectroscopy. The different metal dispersions were found for the samples containing various transition metal oxides. 相似文献
45.
Linssen T Cassiers K Cool P Vansant EF 《Advances in colloid and interface science》2003,103(2):121-147
The most recent developments in the formation of new mesoporous templated zeolitic materials, characterized by surfaces of more than 1000 m(2)/g, are discussed in this paper. By adapting the synthesis parameters, such as type of silicium source, type of template, pH, temperature, em leader different materials can be synthesized with varying porosity and crystallinity. Besides the synthesis, much attention is focused on the activation of their surfaces by incorporation methods or deposition processes towards catalytic applications. Finally, the stability of the different materials, one of the critical parameters to potential industrial applications, is compared and evaluated. 相似文献
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47.
Stevens WJ Lebeau K Mertens M Van Tendeloo G Cool P Vansant EF 《The journal of physical chemistry. B》2006,110(18):9183-9187
Mesoporous SBA-16 and SBA-15 were studied in order to control their possible morphologies. SBA-16 is synthesized using a silicon source (tetraethoxysilane, TEOS) and a ternary system consisting of surfactant F127 (EO106PO70EO106), water, and butanol. The same ternary system, with higher butanol concentration, is used to form SBA-15 material as well. An increase of the TEOS concentration results in a morphology shift of SBA-16 from micron-sized spheres, over randomly shaped aggregated particles, to macrospheres with a size of 15 mm. An identical increase in TEOS concentration also results in the formation of SBA-15 macrospheres, which can be controlled in size. Micron-sized spheres of SBA-15 were formed using a quaternary system of surfactant P123 (EO20PO70EO20), cetyltrimethylammonium bromide (CTAB), ethanol, and water. All mesoporous silica materials were characterized using SEM, XRD, and N2 sorption techniques. 相似文献