Preparation of bimetallic catalysts Ni-Co and Ni-Fe supported on activated carbon for methane decomposition

Abstract

Bimetallic catalysts (Ni-Co/AC and Ni-Fe/AC) supported on activated carbon (AC) were prepared via one-step method from coal as AC precursor with the addition of metal salts by KOH activation. The effects of the introduction of second metal (Co or Fe) into Ni/AC on the textural structure of the resultant bimetallic catalysts and their catalytic performances for methane decomposition were investigated. The results showed that active metals can be directly supported on AC by the reaction of metal species with carbon during the activation. The addition of Co or Fe to Ni/AC resulted in the decrease of specific surface area and pore volume. With increasing the loading of Co or Fe, metal alloys were formed and total surface area and pore volume declined, but the mesoporosity was increased. Bimetallic Ni-Co/AC and Ni-Fe/AC catalysts exhibited better catalytic activity and stability for methane decomposition compared than Ni/AC. The introduction of Co mainly improved initial catalytic activity; however, Ni-Fe/AC catalyst showed better behaviors in terms of reducing the deactivation rate of Ni-based catalyst than Ni-Co/AC catalyst, which is relative with the formation of Ni-Fe alloy and carbon fibers over Ni-Fe/AC. This work provides a simple and efficient approach to improve catalytic performances of Ni-based catalyst for methane decomposition.