Ni含量对介孔Ni-CaO-ZrO2催化剂上CH4-CO2重整反应的影响研究

Influence of Ni content on the catalytic performance of Ni-CaO-ZrO2 catalysts in CH4-CO2 reforming

摘要:

采用并流共沉淀法制备了Ni含量不同的介孔Ni-CaO-ZrO2纳米复合氧化物催化剂，研究了其在CH4-CO2重整反应中的催化性能。利用N2吸附-脱附（BET）、X射线粉末衍射（XRD）、程序升温还原（TPR）以及程序升温氧化（TPO）等手段对催化剂进行了表征。结果表明，Ni含量对催化剂的物化性质和催化性能有较大影响，低Ni含量的催化剂具备较完善的介孔结构，这种结构非常有利于Ni物种的分散及其在高温下的抗烧结能力，从而提高了催化剂的稳定性；但过低的Ni负载量会造成催化剂表面Ni活性位过少，进而影响催化剂的活性；另一方面，Ni含量过高会导致催化剂介孔结构的坍塌，Ni在反应条件下烧结严重，大尺寸的Ni颗粒会大大的增加积碳的生成，从而造成催化剂失活。

Abstract:

Mesoporous Ni-CaO-ZrO2 nano-composites with different Ni content derived from co-precipitation were tested in CH4-CO2 reforming and characterized by means of N2-adsorption/desorption, X-ray diffraction, Temperature programmed reduction/oxidation. It was found that catalysts with lower Ni contents showed better mesoporous structure, and such framework could enhance the dispersion of Ni particles and avoid their sintering during reaction, which in turn promoted the stability of catalysts. however, activity of the catalyst decreased drastically if the content of Ni was too low. On the other hand, too higher lever of Ni content would cause the collapse of the mesoporous structure, sever sintering and so-caused deactivation were happened during reaction.