No abstract

A synergistic approach was made to develop a highly stable and carbon resistant catalyst system based on cobalt and nickel supported over modified mesoporous silica for the dry reforming of methane (DRM). Modified mesoporous silica is prepared by a hydrothermal method, and the total Co & Ni composition is taken at around 5% by using the deposition-precipitation technique. CO2 reforming with methane was performed at 400-800 °C under atmospheric pressure as well as at a pressure of 1 MPa, keeping the CH4/CO2 ratio equal to unity. The catalyst assembly before and after the reaction was thoroughly characterized by a wide range of analytical techniques including N2 physisorption, XRD, TPR, TPO, TPH, XPS, SEM, TEM, elemental mapping, TG-DTG. The physicochemical characterization results confirmed the homogeneous distribution of nanosized metal particles into the hexagonal framework of modified silica, which plays a vital role towards a stronger metal support interaction that renders carbon deposition upon the active metal surface as well as avoids metal sintering at higher temperatures. At the same time, the coexistence of nanosized Co and Ni into the mesopores produced a synergy which provides better stability without any deactivation at high pressure reaction conditions. In situ DRIFT analysis evidenced that the reaction proceeds over these catalysts through an initial pathway in which both methane and carbon dioxide initially dissociate over the metal along with a bifunctional pathway in which methane dissociates over the active metal and carbon dioxide activated over the basic support surface via a formate intermediate. Density Functional Theory (DFT) calculations were also performed and further support the proposed mechanism from DRIFT studies.

No abstract

Nanosized Ru (1 wt %) supported over CeO 2 − ZrO 2 solid solution nanorods have been prepared via a one step hydrothermal approach and verified its activity in partial oxidation of methane at 800 °C with CH 4 : O 2 = 2:1 for 200 h in a downflow, fixed-bed, microreactor. The so prepared catalysts have been characterized with a variety of analytical tools. Characterization results confirm higher dispersion of nanosized Ru over CeO 2 −ZrO 2 solid solution possess strong metal support interaction and higher oxygen storage capacity of the CeO 2 −ZrO 2 solid solution in comparison to only ceria or zirconia. We do not observe any deactivation during 200 h TOS study with 1% Ru supported over CeO 2 −ZrO 2 solid solution, whereas there is a significant activity loss due to coke deposition; metal oxidation it observed only with ceria-or zirconia-supported catalysts.

The solvent-free microwave extraction of essential oil from ginger was optimized using a 2 3 full factorial design in terms of oil yield to determine the optimum extraction conditions. Sixteen experiments were carried out with three varying parameters, extraction time, microwave power, and type of sample for two levels of each. A first order regression equation best fits the experimental data. The predicted values calculated by the regression model were in good agreement with the experimental values. The results showed that the extraction time is the most prominent factor followed by microwave power level and sample type for extraction process. An average of 0.25% of ginger oil can be extracted using current setup. The optimum conditions for the ginger oil extraction using SFME were the extraction time 30 minutes, microwave power level 640 watts, and sample type, crushed sample. Solvent-free microwave extraction proves a green and promising technique for essential oil extraction.