Pt/CeO2-ZrO2变换催化剂的制备、表征与性能

 用共沉淀法制备了不同Ce/Zr比的CeO2-ZrO2复合氧化物,用浸渍法制备了Pt/CeO2-ZrO2水煤气变换催化剂,并对该催化剂进行了活性评价. 结果表明,与传统的Cu基低变催化剂相比,该催化剂具有操作温度范围宽和抗氧化冲击等优点,具有应用于车载重整制氢过程的潜力. 考察了温度、空速和汽/气比等条件对催化剂活性的影响,对催化剂的制备参数和工艺参数进行了研究. 结果表明,不同Ce/Zr比的Pt/CeO2-ZrO2催化剂的活性相差很大,其中Pt/Ce0.8Zr0.2O2变换催化剂活性最高. XRD结果表明,制备的Pt/Ce0.8Zr0.2O2形成了固溶体. 通过增加单位质量催化剂表面的Pt原子数可提高催化剂的活性.

Preparation,Characterization and Performance of Pt/CeO2-ZrO2 Water Gas Shift Catalyst

CeO 2-ZrO 2 composite oxide with different Ce/Zr ratios was prepared by co-precipitation and a series of Pt/CeO 2-ZrO 2 catalyst samples for water gas shift reaction (WGS) was prepared by impregnation of CeO 2-ZrO 2 with chloroplatinic acid solution. The activity of these catalyst samples was measured in simulated reforming gas. The parameters of preparation and operation of the catalyst were investigated by comparing CO conversion at different temperatures, space velocities and steam/gas ratios. The optimized composition of the catalyst was attained by adjusting the content of Zr and Pt. The catalyst samples were active in a wider temperature range than the traditional Cu-based low temperature shift catalysts, but their activity was lower than that of Cu-based catalyst at lower temperature. The Pt/CeO 2-ZrO 2 may be a good candidate for the onboard hydrogen production because it is stable when exposed to air at high temperature. The CO conversion decreased with increasing space velocity, and increased with increasing steam/gas ratio. The Pt/Ce 0.8Zr 0.2O 2 catalyst showed the highest activity among the catalyst samples. The activity of the catalyst increased with increasing Pt loading when w(Pt)<0.6%. The XRD result indicated that the solid solution was formed in the CeO 2-ZrO 2 composite oxide. The activity of the catalyst can be improved by increasing the Pt atoms on the support surface.