Novel carbon-Al2O3 and carbon-ZrO2 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 CeO2 to catalysts on the steam reforming of ethanol were investigated. The reactions were carried out in a fixed bed reactor with H2O/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-Al2O3 composite-supported Co catalysts exhibited a higher conversion of ethanol than the carbon-ZrO2 composite-supported Co catalysts, the effect of the addition of CeO2 was hardly observed for catalysts with Al2O3. In contrast to the case of catalysts with Al2O3, the effect of the addition of CeO2 to catalysts with ZrO2 on the conversion and the hydrogen yield was observed, and the hydrogen yield at 600 °C exceeded that of catalysts with Al2O3. 16Co42C31.5Ce10.5Zr exhibited the highest hydrogen yield of 89% at 600 °C. Fine Co metal species were observed for the used ZrO2-based catalysts, while Co3O4 peaks were observed for the used Al2O3-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.
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