علی ایزدبخش

Today, advancements in nanotechnology offer many opportunities for the design and controlled synthesis of the catalyst. The synthesis of nanoscale catalysts improve the activity, selectivity, yield and their stability. In recent years, core-shell nanocomposites because of many catalytic applications are being considered. Coating core by suitable shell cause surface modification, improve performance and increase core stability in different operational conditions. In this study, core-shell nanocomposite with nickel oxide NiO core and mesoporous MCM-41 shell was synthesized by using vesicles self assembly nanoreactore. The effect of storage time of vesicle solution on the size of the core and shell thickness of core-shell nanocomposites were studied. Small angle X-ray diffraction (XRD) analysis, nitrogen adsorption-desorption and transmission electron microscopy (TEM) confirm the formation of core-shell structure as well as the formation of mesoporous mcm-41 shell around the core .The results showed that with increasing storage time of vesicle, core size of the synthesized nanocomposite is larger and their shells become thinner. Following the study, Catalytic performance of synthesized core-shell nanocomposites was studied in the process of dry reforming of methane. Result show that catalyst by 24 hour storage time for vesicles because of suitable distribution of nickel nanoparticles in the core and thinner MCM-41 shell has better performance in contrast other samples. Also the effect of different temperature on the performance of the catalyst was studied. Result show that, catalyst in higher operation temperature 950 Centigrade degree has better performance and the MCM-41 shell protect core from sintering and carbon deposition. The effect of Gas hourly space velocity GHSV was evaluated on the catalyst performance and the results showed that decreasing GHSV result in increasing the contact time between the catalyst and the reactants and lead to the high reaction yields