Abstract
Novel carbon-Al(2)O(3) and carbon-ZrO(2) composite-supported Co catalysts were prepared using the sol-gel method with polyethylene glycol (PEG) as a carbon source, and the effects of the addition of CeO(2) to catalysts on the steam reforming of ethanol were investigated. The reactions were carried out in a fixed bed reactor with H(2)O/EtOH = 12 (mol/mol) and a temperature range of 300 °C to 600 °C. The catalyst characterization was performed by XRD, nitrogen adsorption and desorption isotherms, TG-DTA, XRF and TEM. Although the carbon-Al(2)O(3) composite-supported Co catalysts exhibited a higher conversion of ethanol than the carbon-ZrO(2) composite-supported Co catalysts, the effect of the addition of CeO(2) was hardly observed for catalysts with Al(2)O(3). In contrast to the case of catalysts with Al(2)O(3), the effect of the addition of CeO(2) to catalysts with ZrO(2) on the conversion and the hydrogen yield was observed, and the hydrogen yield at 600 °C exceeded that of catalysts with Al(2)O(3). 16Co42C31.5Ce10.5Zr exhibited the highest hydrogen yield of 89% at 600 °C. Fine Co metal species were observed for the used ZrO(2)-based catalysts, while Co(3)O(4) peaks were observed for the used Al(2)O(3)-based catalysts. The development of the carbon nanotube-like structure with a diameter of 50 nm was observed with particles having diameters of 30 nm to 50 nm, suggesting that the carbon deposition might occur so as not to deactivate the catalyst.