【作者】 王阳；

【导师】 刘源；

【作者基本信息】 天津大学 ， 工业催化， 2007， 硕士

【摘要】 燃料电池技术是未来首选的洁净、高效能源技术,其中燃料电池制氢技术是其技术核心。乙醇水蒸气重整反应展现了在制氢上的优越性,是未来主要的制氢技术之一。在乙醇重整反应中,镍系催化剂具有活性高、成本低等特点,但有氢气选择性较低,且易烧结,积碳导致稳定性不高的缺点。本论文探索开发了一种铈锆复合氧化物负载的镍催化剂,该催化剂在乙醇重整反应中展现了高活性、选择性和良好的抗积碳性能。我们研究和分析了制备因素对其催化性能和催化剂结构的影响。本实验分别采用共沉淀法、浸渍法和柠檬酸络合法制备了一系列Ni/ CexZr_1-xO₂催化剂。考察了制备条件（包括催化剂焙烧温度、柠檬酸和金属离子摩尔比以及活性组分含量）和反应条件（包括还原温度、反应空速）对Ni/ CexZr_1-xO₂催化剂用于乙醇水蒸气重整反应性能的影响,然后选出性能最好的催化剂进行了低温和高温下的稳定性测试。采用X射线衍射,程序升温还原和热重-差热等表征手段分析了催化剂的结构和性能。本工作得到以下主要实验结果:（1） Ni/Ce_0.5Zr_0.5O₂催化剂在以下制备条件下表现出最佳性能:柠檬酸络合法制备,焙烧温度750℃,载体金属离子和柠檬酸摩尔比为1:0.5,Ni含量20wt%;反应的预处理最佳还原温度为550℃。（2）20Ni/Ce_0.5Zr_0.5O₂-700催化剂在160,000ml?h-1?gcat-1高空速条件下仍能表现出很好的活性和选择性。（3）在整个反应温度测试范围内（350～700℃）,20%Ni/Ce_0.5Zr_0.5O₂-700催化剂上乙醇的转化率都达到了100%。（4）对20%Ni/Ce_0.5Zr_0.5O₂催化剂分别在低温350℃和高温550℃进行了6h稳定性测试,6h内活性和选择性没有发生变化。对反应后的催化剂进行了TG-DTA测试,实验结果说明该催化剂在高温下有良好的抗积碳性能。（5）XRD实验结果表明,催化剂的主要物相组成为NiO和铈锆固溶体, NiO的分散程度,NiO和载体的相互作用对催化剂的性能有很大影响。（6）TPR实验结果表明,Ni/Ce_0.5Zr_0.5O₂催化剂上包括NiO和CeO2的还原,Ni0是催化剂的主要活性组分。（7）TG-DTA实验结果表明,20%Ni/Ce_0.5Zr_0.5O₂催化剂在550℃性能测试6小时后没有积碳现象,具有很好的稳定性。更多还原

【Abstract】 Hydrogen is considered to be the energy carrier of the future. Ethanol steam reforming has many advantages over other ways for hydrogen production and will play an important role in producing hydrogen. Ni-based catalysts characterize with high activity and low cost. However, its selectivity towards H2 is relatively low, and catalyst stability is poor as the result of sintering and carbon deposition. In this paper, we used a new method to prepare Ni/Ce-Zr-O catalysts, which showed high activity and good stability for ethanol steam reforming.We investigated the effect of preparation method, calcination temperature, reduction temperature, the molar ratio of metal ion and citric, the content of active component on catalyst performance. We also examined catalyst activity with high space velocity. And the stability test of 20% Ni/Ce_0.5Zr_0.5O₂ catalysts after the reaction 6 hours separately at 350℃and 550℃was carried out. XRD and TPR have been used to investigate the structure and reduction behavior of the samples.TG-DTA has been used to investigate the carbon resistance of catalysts.The main results are as follows:（1）20wt%Ni/Ce_0.5Zr_0.5O₂-700 prepared by sol-gel method showed the best catalytic performance with the reduction temperature at 550℃and the molar ratio of （Ce4++Zr4+: citric acid ） 2:1.（2）The catalysts showed high activity and selectivity even at space velocity of 160,000ml/h.g.cat.（3）The ethanol conversion was 100% at the temperature from 350℃to 700℃over 20wt%Ni/Ce_0.5Zr_0.5O₂-700 catalyst.（4）The stability test is carried out for 6h over 20%Ni/Ce_0.5Zr_0.5O₂ catalyst separately at 350℃and 550℃There is no changes of activity and products selectivities were observed.（5）XRD results indicated that the catalyst include the phase of NiO and Ce0.5Zr0.5O2. Both the distribution of Ni species and the interaction between NiO and CeO2 affected catalysts performance.（6）The active component of Ni0 exists in different forms of catalysts with different preparation conditions. Meanwhile, the interaction between NiO and carrier will affect catalyst performance. （7）TG-DTA results showed no weight loss over 20%Ni/Ce_0.5Zr_0.5O₂ catalyst which is used for 6h at 550℃. So the 20%Ni/Ce_0.5Zr_0.5O₂ catalyst has better anti-carbon deposition property.更多还原