The Study On Co₃O₄/CeO₂ Catalysts For Ethanol Steam Reforming

Fuel cell will become a hotspot as clean and effective energies in future. One of the most important technologies is hydrogen production. Ethanol steam reforming has many advantages over other ways for hydrogen production. So it will be main technology of hydrogen production in future. Many traditional catalysts are used for ethanol steam reforming. Co-based catalysts characterize with high activity and low cost. However, there are many by-products, and catalyst stability is poor as the result of sintering. In this paper, we explored new method to prepare Co-Ce oxide catalysts, which showed high activity and good stability for ethanol steam reforming.Co-Ce oxide catalysts were prepared by co-precipitation method and impregnation method with cobalt nitrate and cerium nitrate as precursors. Many factors were studied such as aging time, the content of active component, calcination temperature, molar ratio of Ce/Ti in carrier, preparation method and space velocity in order to know the effect of these factors on the structure of Co-Ce oxides and on the performance of ethanol steam reforming. The stability test of catalysts with two preparation methods was carried out. XRD and TPR have been used to investigate the structure and reduction behavior of the samples.The main results are as follows:(1) Co/CeO₂ catalyst made by co-precipitation method show best performance with the condition of aging for 24h, 10wt% Co3O4, calcining temperature 650℃; and for catalysts made by impregnation method with the condition of 20wt%Co3O4, calcining temperature 650℃.(2) The catalysts show better activity and selectivity after H2 pretreatment.(3) The addition of Ti is unable to improve the performance of the catalysts.(4) The stability test is carried out for 40h over catalysts prepared by co-precipitation method and impregnation method. The result indicates CeO₂ improve the stability of Cobalt catalysts.(5) XRD resulsts indicate that the catalyst is composed of Co3O4 and CeO₂. Both the distribution of Co species and the interaction between Co3O4 and CeO₂ affect catalysts performance.(6) TPR results indicate that two steps reduce the metal cobalt. Co3O4 is reduced...