CNT and H2 Production during CH4 Decomposition over Ni/CeZrO2. II. Catalyst Performance and Its Regeneration in a Fluidized Bed

In this work, a ceria-zirconia supported nickel catalyst (Ni/CeZrO 2) was for the first time used in a fluidized bed reactor in order to obtain carbon nanotubes (CNTs) and H 2 in the reaction of the decomposition of CH 4. The same catalyst was afterward regenerated with H 2O, which was accompanied with the production of H 2. The impact of catalyst granulation, temperature, and gas hourly space velocity (GHSV) on the amount and type of carbon deposits was determined using thermogravimetric analysis (TGA) and scanning and transmission electron microscopy (SEM and TEM). The presence of randomly oriented and curved CNTs with an outer diameter of up to 64 nm was proved. The Ni/CeZrO 2 particles were loosely covered with CNTs, freely dispersed over CNTs, and strongly attached to the external CNT walls. TEM proved the presence of a Ni/CeZrO 2@CNT hybrid material that can be further used as catalyst, e.g., in WGS or DRM reactions. The impact of GHSV on hydrogen production during catalyst regeneration was determined. The catalyst was subjected to cyclic tests of CH 4 decomposition and regeneration. According to the obtained results, Ni/CeZrO 2 can be used in CH 4 conversion to CNTs and H 2 (instead of CH 4 combustion), e.g., in the vicinity of installations that require methane utilization. View Full-Tex