CO Dissociation on Ni/SiO2: The Formation of Different Carbon Materials

Activity control for CO dissociation over supported Ni catalysts is very important for steam reforming, CO2 reforming, methanation, carbon formation, and other processes. In this work, a series of Ni/SiO2 catalysts were designed through thermal decomposition or dielectric barrier discharge (DBD) plasma decomposition. After a high temperature reduction, the main difference between the two catalysts was the structure of Ni nanoparticles, instead of the particles size. The plasma decomposed catalyst possesses smooth surface on Ni nanoparticles with less defect sites, leading to the activity control of CO dissociation. DBD plasma decomposed Ni/SiO2 catalysts have a low activity for CO dissociation with a low final carbon yield. The as-produced carbon materials over thermally decomposed or plasma decomposed are in the form of carbon onion particles or carbon nanotubes, separately. The growth mechanism of these two different carbon materials was also discussed.