Molecular perspective of MoS2/Co unsupported catalyst using computer assisted TEM simulations

ABSTRACTUnderstanding the morphology of catalytically active materials has been approached successfully in past decades using field electron microscopy in scanning and transmission modes. In this respect, some simulated TEM measurements for unsupported promoted molybdenum di-sulfide (MoS2/Co) provided some insights about molecular structure in those catalytic layered transition metal sulfides (LTMS). However, due to poor resolution, lack of color enhancement, and other factors, sections of those materials observed under TEM do not resolve the structure by itself; in particular about the localization of cobalt atoms for promoted MoS2 unsupported catalyst. This work concludes an epitaxial growth of MoS2 slabs over (111)-Co9S8 crystallographic plane, with a stacking degree size of 6 slabs. Results presented in here are obtained using experimental HRTEM and TEM simulations using the multi-slice method with a slice thickness of 25 Å and projected potential$f(U) = \sum\limits_{i = 1}^n {a_i e^{(- b_i U^2)} } $, where ai and bi are coefficients to be determined.

Biodiesel Production from Jatropha curcas Oil Using Potassium Carbonate as an Unsupported Catalyst

Jatropha curcas (JTC) oil, an inedible vegetable oil, can be a substitute feedstock for traditional food crops in the production of environment friendly and renewable fuel (biodiesel). In the present study, unsupported potassium carbonate was used as a catalyst to provide an understanding of the catalytic activity in the transesterification reaction. Researching the potential and the behavior of potassium carbonate is very important because every biomass ash contains this compound in a significant amount. It can be extracted by using classical extraction or leaching technologies. During the biodiesel production reaction, the formation of soap as a byproduct was also monitored using the FTIR-ATR method. From this study it was observed that the transesterification of JTC oil to JTC biodiesel appeared to be complete within 15 minutes when a 5 wt% (based on the wt. of the oil) potassium carbonate, 6:1 methanol to oil molar ratio, 60°C or a 4 wt% potassium carbonate, 9:1 methanol to oil molar ratio and 60°C reaction temperature were used.