预处理方法对Ni-Co双金属催化剂性能与结构的影响

浸渍法制备了Ni-Co/La₂O₃-γ-Al₂O₃双金属催化剂, 经氢气还原预处理后, 再分别由一氧化碳、甲烷和二氧化碳进行再次预处理, 考察了预处理方法对该催化剂上沼气重整制氢性能的影响, 并运用X射线衍射(XRD)、热重-差示扫描量热(TG-DSC)、透射电子显微镜(TEM)等手段对催化剂进行了表征. 结果表明, 与传统氢气还原预处理相比, 经氢气与一氧化碳预处理后, 催化剂性能无明显变化; 经氢气与甲烷预处理后, 催化剂性能明显变差; 而经氢气和二氧化碳预处理后, 催化剂性能明显变优, 且能基本消除该催化剂上沼气重整反应的诱导期. 分析结果表明, 经氢气和二氧化碳预处理后, 催化剂中金属颗粒较小, 分布较均匀, 粒径分布范围较窄, 从而减少了催化剂表面碳的沉积, 增强了催化剂的抗积炭性能, 可延长催化剂的使用寿命.

Effect of Pretreatment Routes on the Performance and Structure of Ni-Co Bimetallic Catalysts

Ni-Co/La₂O₃-γ-Al₂O₃ catalysts for biogas reforming were prepared by conventional incipient wetness impregnation and pretreated first by hydrogen reduction and then by pure carbon monoxide, methane and carbon dioxide, respectively. The effect of pretreatment route on the biogas reforming performance of the catalysts was investigated. The catalysts were characterized with X-ray diffraction (XRD), thermogravimetric and differential scanning calorimetry (TG-DSC), and transmission electron microscopy (TEM), and the relationship between the performance and the structural properties of the catalysts was investigated. The results indicated that, compared with the performance of catalysts pretreated by the traditional hydrogen reduction, the performance of catalysts pretreated by hydrogen and carbon monoxide did not change significantly, while the performance of catalysts pretreated by hydrogen and methane deteriorated obviously. Nevertheless, the performance of catalysts pretreated by hydrogen and carbon dioxide was dramatically enhanced and the long adjustment period of the biogas reforming catalysts was basically eliminated. The characterization results showed that the active metal particle size of the catalysts pretreated by hydrogen and carbon dioxide was smaller on average and distributed more evenly and much more narrowly, which notably enhanced the catalysts'' carbon resistance and prolonged the catalysts'' longevity.