Catalysis Today, Vol.317, 76-85, 2018
Nickel catalysts supported on ordered mesoporous SiC materials for CO2 reforming of methane
Ordered mesoporous SiC materials with different architectures were facilely prepared by a nanocasting method using SBA-15, KIT-6 and MCM-41 as hard templates, and the latter obtained nickel-containing SiC materials were applied to the dry reforming of methane. After reacting at 750 degrees C for 25 h, the catalytic activity and stability are declined in the sequence of Ni/SiC-KIT-6 > Ni/SiC-SBA-15 > > Ni/SiC-MCM-41. Physicochemical properties of prepared mesoporous Ni/SiC catalysts were further characterized by using N-2 adsorption, inductively coupled plasma atomic emission spectrometer (ICP-AES), X-ray diffraction (XRD), H-2 chemisorption, temperature programmed reduction (TPR), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA) etc. The characterization results showed that both Ni/SiC-KIT-6 and Ni/SiC-SBA-15 inherit the ordered mesoporous structure from their mother templates, while Ni/SiC-MCM-41 had a poor mesoporous structure since the pore size of MCM-41 is too narrow to penetrate precursors. Ni/SiC-KIT-6 showed strong confinement effect of three-dimensional bicontinuous mesoporous structure, leading to the well dispersion/anchoring of metal particle inside the pores and strong metal support interaction. Meanwhile, Ni/SiC-SBA-15 showed a confinement effect of two-dimensional channel arrays but with a few large Ni particles outside the mesopores, which may result in the carbon deposition and catalytic deactivation. And due to the rigid confinement effect and the superior structure stability at high temperatures, Ni/SiC-KIT-6 showed the excellent catalytic activity and stability for dry reforming of methane.
Keywords:Ordered mesoporous SiC;Nanocasting;Confinement effect;Methane;Dry reforming;Carbon deposition