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Nickel nanoparticles supported on silica for the partial oxidation of isooctane
Applied Catalysis A: General ( IF 5.5 ) Pub Date : 2017-08-14 , DOI: 10.1016/j.apcata.2017.08.015
Qusay Bkour , Oscar G. Marin-Flores , Trent R. Graham , Parissa Ziaei , Steven R. Saunders , M. Grant Norton , Su Ha

A Ni-based nanoparticle catalyst was synthesized over a silica support via wet impregnation using either ethylene glycol or water. X-ray diffraction and transmission electron microscopy analysis showed that the particle size of the Ni catalyst prepared using ethylene glycol as the solvent tended to be smaller than that obtained when water was used. The resulting catalysts were tested for performance toward partial oxidation (POX) of isooctane at high weight hourly space velocities (WHSV). The results were compared with those from a Rh-based catalyst, which is commonly used for the same reaction. At a WHSV of 13.8 h−1, a Ni/SiO2 catalyst with an average Ni particle size of 6.8 nm exhibits higher catalytic activity and stability with an improved resistance to carbon formation than a Ni/SiO2 catalyst with an average Ni particle size of 16.6 nm. The catalyst with the smaller Ni particles outperformed the supported Rh catalyst for the POX of isooctane. To further improve the Ni dispersion and enhance its ability to run at even higher WHSVs with milliseconds of residence time, ceria was used as a promoter. The ceria-promoted Ni catalyst was also prepared by the wet impregnation method using ethylene glycol as the solvent. The addition of ceria corresponded with a further reduction in the size of the Ni nanoparticles and improved Ni dispersion. Using the Ni-Ce/SiO2 catalyst the WHSV could be increased up to 20.0 h−1 while still maintaining its good catalytic activity. At this high WHSV of 20.0 h-1, the Ni/SiO2 catalyst without the ceria promoter and the Rh catalyst showed severe deactivation due to the formation of surface carbon deposits.



中文翻译:

负载在二氧化硅上的镍纳米颗粒,用于异辛烷的部分氧化

使用乙二醇或水通过湿法浸渍在二氧化硅载体上合成了镍基纳米颗粒催化剂。X射线衍射和透射电子显微镜分析表明,使用乙二醇作为溶剂制备的Ni催化剂的粒度倾向于小于使用水时获得的Ni催化剂的粒度。测试所得催化剂在高重量时空速(WHSV)下对异辛烷的部分氧化(POX)的性能。将结果与通常用于同一反应的Rh基催化剂的结果进行了比较。在WHSV为13.8 h -1时,Ni / SiO 2与平均Ni粒径为16.6 nm的Ni / SiO 2催化剂相比,平均Ni粒径为6.8 nm的催化剂显示出更高的催化活性和稳定性,并具有更好的抗碳形成性。对于异辛烷的POX,具有较小Ni颗粒的催化剂的性能优于负载型Rh催化剂。为了进一步改善Ni的分散度并增强其在更高的WHSV且以毫秒为单位的停留时间下运行的能力,氧化铈被用作促进剂。还通过使用乙二醇作为溶剂的湿法浸渍法制备了二氧化铈促进的Ni催化剂。二氧化铈的添加对应于Ni纳米颗粒尺寸的进一步减小和Ni分散性的改善。使用Ni-Ce / SiO 2催化剂,WHSV可以增加到20.0 h-1,同时仍保持其良好的催化活性。在20.0 h -1的高WHSV下,由于形成了表面碳沉积,没有二氧化铈助催化剂和Rh催化剂的Ni / SiO 2催化剂严重失活。

更新日期:2017-08-14
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