Abstract:

WC zeolite nanocomposite was synthesized by combining a mechano-chemical approach with the reduction-carbonization technique. We used natural zeolite as a support and ammonia metatungsten as a tungsten source. The pretreated zeolite was mixed with ammonia metatungsten at a n(Si):n(W)=2:1 by a ball miller to produce the WO3/zeolite precursor. The precursor was then reduced and carbonized in a CH4/H2 atmosphere at 1173 K in a furnace for a specific period of time. The product was characterized by X-ray diffraction (XRD), scanning electron microscopy(SEM), and X-ray energy diffusive spectroscopy (EDS). Results showed that the sample was composed of monotungsten carbide, bitungsten carbide, quartz, mordenite, and clinoptilolite. The diameter of the monotungsten carbide particles was found to be about 30 nm and that of bitungsten carbide about 20 nm. The electrocatalytic activity of the sample for p-nitrophenol in a neutral solution was measured using a powder microelectrode. Results show that the sample is electrocatalytically active in a neutral p-nitrophenol solution. The electrocatalytic activity of these samples is better than that of mesoporous tungsten carbide and this is due to the mass fraction of WC and the ratio of w(WC)/w(W2C). These results indicate that a synergistic effect exists between the tungsten carbide and the zeolite.

Key words: Tungsten carbide, Natural zeolite, Nanocomposite, Electrocatalytic activity, Synergistic effect