The Studies On Preparation Of Loaded With Ruthenium Nanoparticles Catalysts Using Supercritical Fluid Deposition Technology

In this paper,activated carbon as the carrier,ruthenium chloride of inorganic metalliccompounds as the active precursor,supercritical carbon dioxide as the solvent preparation forRu/C catalyst using supercritical fluid deposition method.The main content of the articleincludes two aspects as below:（1）The research of Ru/C catalysts under hydrogen reductivecondition in supercritical fluid.（2）The research of Ru/C catalysts under potassium borohydridereductive condition in supercritical fluid.The main experiments and results are as follows:（1）The research of Ru/C catalysts under hydrogen reductive condition in supercriticalfluid.The activity of Ru/C catalysts for hydrogenation of glucose were tested.We also studiedthe effects of kinds of the cosolvent,the cosolvent amount,the supercritical CO₂pressure andthe supercritical CO₂temperature on catalytic activity. The results showed that the activity ofRu/C catalysts prepared by supercritical fluid deposition was superior to the traditional waterimpregnation dry reduction method.The activity of Ru/C catalysts were influenced by kindsof the cosolvent,the cosolvent amount,the supercritical CO₂pressure and the supercritical CO₂temperature.The Ru/C catalysts prepared under the condition of methanol cosolvent2ml,supercritical CO₂pressure12.0MPa and supercritical CO₂temperature250℃had thehighest activity,which was1.49times that of the catalyst prepared by traditional waterimpregnation dry reduction method.The samples were characterized by XRD and XPS.Theresults showed that the active component ruthenium had a well distributed on the activecarbon carrier and existed on an amorphous state. As between ruthenium and the catalystcarrier had a strong interaction force,the aggregation was impossible to happen.（2）The research of Ru/C catalysts under potassium borohydride reductive condition insupercritical fluid.The effects of preparation condition for Ru/C catalysts,ie,temperature,theamount of CO₂and the amount of reducing agent potassium borohydride,on activity of theRu/C catalysts were investigated by orthogonal experiment.The results indicated that theeffects of properties of the Ru/C catalysts decreased in temperature, amount of CO₂and theamount of reducing agent potassium borohydride.The best process conditions of Ru/Ccatalysts was that the amount of methanol cosolvent was0.5ml,the temperature was60℃,CO₂ volume was40ml,the amount of reducing agent potassium borohydride was0.10g.The bestcatalytic activity was28.3mmol·min^-1·g^-1which was1.89times than the preparation ofcatalyst used traditional water impregnation method.The samples were characterized byinfrared spectrum,scanning electron microscopy （SEM）,differential scanningcalorimetry（DSC）,transmission electron microscopy （TEM） and BET.The results showed thatruthenium trichloride in combination with the particulate carbon was not a simple physicaladhesion, but rather a chemical reaction occurs and infrared absorption peaks of activatedcarbon were changed.The activated carbon kept the original surface morphology,ruthenium ofdistribution was very uniform in supercritical fluid,the average particals size of rutheniumwere2.2nm.The higher catalytic activity,the stronger the absorption capacity and the strongerapplication force between the active centrosome and the carrier.Large surface area wasconducive to the dispersion of the active component was helpful to improve the catalyticactivity.