Effects of Promoters on the Structure, Performance, and Carbon Deposition of Ni-Al2O3 Catalysts for CO2–CH4 Reforming

High Resolution Image Download MS PowerPoint Slide Modified Ni-Al 2 O 3 catalysts with Ca, Co, and Ce species as promoters were prepared by the combustion method, and the structure, morphology, reduction characteristic, and CO 2 –CH 4 reforming of the catalysts were discussed by X-ray diffraction (XRD), H 2 -temperature-programmed reduction (H 2 -TPR), energy-dispersive X-ray (EDX) mapping, NH 3 -temperature-programmed desorption (NH 3 -TPD), N 2 adsorption–desorption, thermogravimetric-differential thermal analysis (TG-DTG), and temperature-programmed hydrogenation (TPH) methods. The crystal size of Ni on Ca-Ni-Al 2 O 3 was 16.97 nm, and the active component and additive were distributed well in the catalyst. Co-Ni-Al 2 O 3 presented a surface area of 65.70 m 2 ·g –1 and a pore diameter of 161.60 nm. Ce-Ni-Al 2 O 3 showed relatively stable nickel–aluminum spinel (NiAl 2 O 4 ), which could not be easily reduced to the active component Ni. Evaluation results demonstrated that the performance of the catalysts followed the order Co-Ni-Al 2 O 3 > Ca-Ni-Al 2 O 3 > Ni-Al 2 O 3 > Ce-Ni-Al 2 O 3 . Carbon deposition analysis showed that the carbon resistance of Ca-Ni-Al 2 O 3 was poor and graphitic carbon was generated on the catalyst. However, Ce-Ni-Al 2 O 3 showed less carbon deposition, which might have resulted from the lower activity of the catalyst.