Catalyst Preparation、Characterization And Activity Evaluation For Ethanol Steam Reforming

H₂pollution-free energy is replaceable of fossil fuel, and that the process ofhydrogen production from ethanol steam reforming have been proved viable. Ethanol hasmany advantages such as low toxicity, easy transportation, facile storage, reproducibleand so on, and hydrogen production from ethanol steam reforming has wide applicationprospects. At present, some problems are existed:①Catalysts selective is not highenough.②Catalysts deactivate easily without enough stability.③It is necessary tofurther research on the catalytic reaction mechanism, catalyst composition, therelationship between catalyst structure and properties.Y₂O₃-ZrO₂support was prepared by two-step precipitation method with ammoniaand oxalic acid and a series of Cu-Ni/Y₂O₃-ZrO₂catalysts were prepared byimpregnation method. The catalysts were characterized by the X-ray powder diffraction（XRD） and the scanning electron microscope （SEM） results. The activity of catalysts inethanol steam reforming was studied through minitype active evaluation device. Theeffects of the catalyst composition including the atoms mole ratio of Y and Zr in carrier,the load of active components and the active atoms mole ratio on the ethanol conversionwere discussed. The results showed that the reaction activity of the catalysts is lower andtetragonal phase is weaker when the Y content of the catalyst become larger, and Y:Zr=1:9is the best. When the mole ratio of Cu to Ni is1:9and the mole ratio of activecomponents to support is1:1, the activity of ethanol steam reforming reaction is thehighest of all the catalysts. Moreover, the reaction temperature has significant effects onethanol conversion and products selectivity, and ethanol conversion attain to98%at623K on1Cu9Ni/1Y9Zr catalyst. And that the catalysts activity becomes lower at673Kor723K to varying degrees when the mole ratio of Cu to Ni is more than3:7, which isproved to be caused of carbon deposition by SEM results. However, the carbondeposition can be eliminated through gasification reaction.To study the ethanol steam reforming reaction mechanism of1Cu9Ni/1Y9Zrcatalyst,1Cu9Ni/1Y9Zr catalyst activity of ethanol, aldehyde, acetic acid, acetone, CO,CH₄, and CO₂steam reforming reaction were evaluated respectively. The results showedthat two reaction paths of ethanol-ethyoxyl-aldehyde-final products （H₂, CO₂） andethanol-ethyoxyl-aldehyde-acetone-final products were found on the catalyst. And thatCO water gas shift reaction （WGSR） always happens accompanying in the reaction route.Moreover, WGSR activity of1Cu9Ni/1Y9Zr catalyst is highest at673K and the reactionactivity of CH₄steam reforming is always increasing with the increasing temperature.