Carola Contreras, MSc Candidate.

DEPARTMENT OF CHEMISTRY

CHEMISTRY 601/603

INORGANIC SECTION

 

SPEAKER:            Carola Contreras, MSc Candidate.

DATE:                     Tuesday, November 10, 2009.

TIME:                      12:30 pm

PLACE:                  ES 136...Please note room change

TITLE:                  "Development of a New Methodology for Preparing Nanometric Ni, Mo and NiMo Catalytic Particles Using Transient Emulsions"        

                                

ABSTRACT: 

This study is concerned with the development of simple and novel methodology to prepare nanoparticles of Ni, Mo and NiMo 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 particle size is indeed an important variable with particles in the range of 10 nm having superior catalytic activity than the those with sizes of 100 nm and higher, being the activity of the smaller ones double than the activity for the bulk materials with sizes in the order of micrometers.

Mo, Ni and NiMo 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 NiMo catalysts having the most promising characteristics.