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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,该种结构非常有利于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颗粒会大大增加积炭的生成,从而造成催化剂失活。
The mesoporous Ni-CaO-ZrO2 nanocomposite catalysts with different Ni contents were prepared by cocurrent coprecipitation method and their catalytic performance in CH4-CO2 reforming reaction was studied. The catalysts were characterized by N2 adsorption-desorption (BET), X-ray powder diffraction (XRD), temperature programmed reduction (TPR) and temperature programmed oxidation (TPO) The results show that the Ni content has a great influence on the physico-chemical properties and catalytic performance of the catalyst. The catalyst with low Ni content has better mesoporous structure, which is very favorable for the dispersion of Ni species and its anti-sintering ability under high temperature , Which improves the stability of the catalyst; but too low Ni loading will cause too little Ni activity on the catalyst surface, thereby affecting the activity of the catalyst; the other hand, the high content of Ni will lead to the collapse of the catalyst mesoporous structure, Ni In the reaction conditions, sintering serious, large size Ni particles will greatly increase the formation of coke, resulting in catalyst deactivation.