"PALLADIUM ON COAL" CATALYST OBTAINED BY PYROLYSIS OF POWDER CELLULOSE GRANULES IM-PREGNATED WITH PALLADIUM NITRATE

By pyrolysis of powdered cellulose granules impregnated with palladium nitrate, catalysts of 1–8% Pd / C were obtained. Pyrolysis was carried out in a reactor with a water seal at 600 ° C. Metal reduction was carried out with pyrolysis gases and matrix carbon. It was found that the ash content of powdered cellulose granules is ~ 40 times less than the ash content of sulfate cellulose, from which they were made. It was shown by X-ray phase analysis and electron microscopy that palladium in the catalysts is present in the form of Pd (0) nanoparticles uniformly covering carbon fibers and shapeless massive metal precipitates up to 20 μm in diameter. In catalysts 1–3% Pd / С, nanoparticles 10–40 nm dominate (> 95%), in 8% Pd / С, 20–70 nm. The share of massive metal formations in Pd (1%) / C, Pd (3%) / C and Pd (8%) / C is: ~ 2%, ~ 5% and ~ 60%, respectively. They consist of aggregated spherical particles 0.05–0.15 µm in diameter. XRD palladium oxide was not detected in the catalysts. The presence of palladium nitrate in powdered cellulose during its carbonization has a significant effect on the formation of the carbon matrix. With an increase in the content of palladium nitrate in powdered cellulose, the yield of carbon material decreases and its total porosity increases. Infrared spectroscopy revealed the presence of oxygen-containing ether groups in the carbon matrix of palladium catalysts. The activity of catalysts in the model process of decomposition of hydrogen peroxide increases with increasing dispersion of palladium nanoparticles.

Palladium Oxide Nanoparticles: Preparation, Characterization and Catalytic Activity Evaluation

Stable palladium oxide nanoparticles were prepared in aqueous suspension with a very simple procedure, by dissolving palladium nitrate in water at a concentration around 10−4 M. UV-visible absorption spectroscopy was adopted to follow the formation of these nanoparticles, which were characterized by TEM microscopy, along with XRD, XPS and Raman measurements. DFT calculations allowed to interpret the Raman data and to clarify the species present at the surface of the nanoparticles. The catalytic activity of the latter was evaluated by monitoring the reduction of p-nitrophenol to p-aminophenol. This investigation paves the way to the use of these colloidal nanoparticles in processes of heterogeneous catalysis, in particular those concerning the catalytic degradation of aromatic derivatives that represent a serious danger for the environment as pollutants, as in the case of p-nitrophenol.

One Pot Synthesis and Characterization of Palladium [Pd(Anil-Tolu)4(H2O)2]by insitu Method

The insitu synthesis of Schiff base metal complex using p-toluedine (p-tolu), p-anisaldehyde (p-anisal) as starting materials with Palladium nitrate hexahydrate (Pd(NO3)2.6H2O) as a metal precursor in the molar ratio (1:1:1 M) at room temperature. The prepared metal complex is washed with several times with ethanol and boiled water for the removal of un-reacted materials completely. To confirm the prepared material by the following characterization like UV-visible spectroscopy, Fourier Transforms Infrared spectroscopy, X-ray diffraction pattern and Cyclic Voltammetry.

Rice Husk Derived Porous Silica as Support for Pd and CeO2 for Low Temperature Catalytic Methane Combustion

The separation of Pd and CeO2 on the inner surface of controlled porous glass (CPG, obtained from phase-separated borosilicate glass after extraction) yields long-term stable and highly active methane combustion catalysts. However, the limited availability of the CPG makes such catalysts highly expensive and limits their applicability. In this work, porous silica obtained from acid leached rice husks after calcination (RHS) was used as a sustainable, cheap and broadly available substitute for the above mentioned CPG. RHS-supported Pd-CeO2 with separated CeO2 clusters and Pd nanoparticles was fabricated via subsequent impregnation/calcination of molten cerium nitrate and different amounts of palladium nitrate solution. The Pd/CeO2/RHS catalysts were employed for the catalytic methane combustion in the temperature range of 150–500 °C under methane lean conditions (1000 ppm) in a simulated off-gas consisting of 9.0 vol% O2, and 5.5 vol% CO2 balanced with N2. Additionally, tests with 10.5 vol% H2O as co-feed were carried out. The results revealed that the RHS-supported catalysts reached the performance of the cost intensive benchmark catalyst based on CPG. The incorporation of Pd-CeO2 into RHS additionally improved water-resistance compared to solely Pd/CeO2 lowering the required temperature for methane combustion in presence of 10.5 vol% H2O to values significantly below 500 °C (T90 = 425 °C).