Ni/ZrO_2催化乙醇水蒸气重整制氢

Production of Hydrogen by Ethanol Steam Reforming over Ni/ZrO_2 Catalyst

采用化学沉淀法制备了平均粒径分别为58.6nm和11.7nm的ZrO2载体,并采用湿法浸渍负载Ni,制备了负载量(质量分数)为15%的Ni/ZrO2催化剂,分别记为NZ-1和NZ-2催化剂。透射电子显微镜及X射线衍射表征结果显示,NZ-1催化剂的载体与活性组分颗粒间存在一定的团聚现象;而NZ-2催化剂的载体与活性组分颗粒间相互分散情况很好,且颗粒粒径处于同一水平,呈现出新型纳米构筑多功能催化剂的形态。程序升温还原及X射线衍射表征结果显示,两种催化剂的活性组分与载体间都存在一定的相互作用,且这种相互作用随载体粒径的减小而显著增强。在液态空速45h-1、常压、923K的条件下,两种催化剂都可高效催化乙醇水蒸气重整制氢,乙醇转化率为100%。NZ-2催化剂具有更好的催化稳定性,表明这种纳米构筑催化剂在乙醇水蒸气重整制氢中具有良好的应用开发前景。

Two zirconia supports with average particle sizes of 58.6 nm and 11.7 nm were prepared seperately by chemical precipitation method. Two Ni/ZrO2 catalysts （ namely NZ - 1 and NZ - 2） with Ni mass fraction 15% on the two corresponding zirconia supports were prepared by impregnation method. The catalysts were characterized by means of TEM, XRD and H2 - TPR. In NZ - 1 catalyst, aggregation somewhat exists between particles of support and active component Ni. While in NZ -2 catalyst, the particles of the support and Ni is dispersed homogeneously, without obvious aggregation. Since the sizes of the Ni and ZrO2 particles are similar in NZ- 2 catalyst so that the catalyst shows a new form of multifunctional catalytic nanoarchitecture. In both catalysts, support particles and Ni more or less interact. Decrease of support particle size intensifies the interaction. Under conditions of LHSV 45 h^-1 ,923 K and atmospheric pressure, both catalysts exhibited high catalytic activity with 100% ethanol conversion. Especially, the NZ -2 catalyst exhibited extremely good catalytic stability.