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

Abstract

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.