Development of a new methodology for preparing nanometric ni, mo and nimo catalytic particles using transient emulsions
Date
2009
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Abstract
This study is concerned with the development of a simple and novel methodology to prepare Ni, Mo and NiMo based nanoparticles for their use as hydrodesulphurization catalysts with potential for in situ and above-ground hydroprocessing of heavy oil, and the correlation of particle size with their catalytic activity. The inorganic nanoparticles were prepared using thermal decomposition of transient emulsions. Transient emulsions (TEs) were defined as those emulsions sustained by the energy supplied to create them, but when that energy source is cut out, the emulsion tends to brake in a short frame of time. A study was done taking into consideration different parameters for the preparation of the transient emulsions, including the concentration of the precursor molecules, the water percentage, the use of surfactant, and the manner of mixing the various solutions. The characteristics of these minute materials depend largely on particle size. Characterization was done via DLS, TEM, EDS, Raman and XRD. Also, a reactivity test to evaluate the performance of the catalyst particles produced for upgrading VGO was carried out. To understand the catalysts activity dependence on size, molybdenum sulphide particles were prepared by a new simple methodology using a capping agent to control the particle growth and their catalytic activity was tested. The results obtained indicated that the particle size is indeed an important variable and particles in the range of 10 nm have superior catalytic activity than the materials with particle sizes of 100 nm and higher, being double than the activity for the bulk materials. The particles prepared via TEs presented average diameters in the nanosize scale being composed of agglomerates of sizes varying from around 350 nm to 500 nm depending on the conditions used for the preparation with primary particle sizes as low as 35 nm. These particles showed catalytic activity with the NiMoS type of catalysts showing the most promising characteristics.
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Bibliography: p. 108-116
Some pages are in colour.
Some pages are in colour.
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Citation
Contreras Lapeira, C. (2009). Development of a new methodology for preparing nanometric ni, mo and nimo catalytic particles using transient emulsions (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/3212