Characterization and Catalytic Activity of Different Carbon Supported Pd Nanocomposites

Abstract

In our experiments, high nitrogen content N-doped multiwall carbon nanotubes (N-CNTs) were synthetized by chemical vapour deposition (CVD) method, after these nanotubes were used as dehydrogenation catalyst support. The chemical nature of the nitrogen atoms in graphitic lattice of N doped CNT was characterized with X-ray photoelectron spectroscopy (XPS) analysis, the pyridinic and graphitic nitrogen atoms were located in nanotube wall. The lattice defects of N-CNT structure were checked with Raman spectroscopy, according to which many defect were present in structure of N-CNTs, owing to the incorporated nitrogen atoms. The formed oxidized N-doped CNT samples were studied by Fourier transform infrared (FT-IR) spectroscopy, according to the test, many oxygen content surface functional groups were identified (COOH, OH and C=O). Palladium nanoparticle morphology and surface on the catalyst substrates were characterized by high resolution transmission electron microscopy (HRTEM) and X-Ray diffraction (XRD) methods. The diameters of palladium particles were slightest in case of carbon nanotube supported catalyst (2 nm), smaller than case of activated carbon, due to absence of microporosity and presence of functional groups on the N-CNT surface. The catalytic activity of the CNT supported catalysts was compared to an active carbon and norit supported samples. The dehydrogenation of C2H6 has been investigated on Pd deposited on various carbon supported catalysts at 573–973 K. On the Pd/CNT catalyst the highest selectivity was reached to ethene (85 %) at 973 K. The most active Pd/Ac achieved 64 % conversion at 973 K.