Catalysis Today, Vol.357, 214-220, 2020
CO2 methanation under dynamic operational mode using nickel nanoparticles decorated carbon felt (Ni/OCF) combined with inductive heating
Carbon dioxide (CO2) hydrogenation to methane (CH4) (Sabatier reaction) is a fundamental process that meets with several key challenges of our modern society. Besides representing a convenient way to the metal-mediated conversion of a natural and abundant "waste" into a fuel of added value, its combination with H-2 from renewable resources (REs) represents a challenging technology for the REs storage. In addition, its practical exploitation can give a concrete answer to many critical societal and environmental issues largely related to the steadily increase of CO2 concentration in the Earth's atmosphere caused by the main anthropic activities. Although many fundamental achievements have also been reached since its discovery at the beginning of the twentieth century, alternative and conceptually new protocols for the process can provide valuable solutions to the optimization of the catalyst performance, process energetics and catalyst life-time on stream. This contribution describes the synthesis of an efficient and robust catalyst for the CO2 methanation, based on Nickel nanoparticles (Ni-NPs) grown on electrically conductive and macroscopically shaped oxidized carbon-felt disks (OCF), heated at the target reaction temperature by electromagnetic induction. At odds with the more classical external heat sources (based on contact heat conduction), induction heating allows the electromagnetic energy to be directly absorbed by the susceptor (OCF) who converts it into heat to be transferred to the catalyst active sites (Ni NPs). Inductive heating (IH) of Ni/OCF gives CO2 conversion (X-CO2) up to 74% and CH4 selectivity (S-CH4) close to 97% already at 320 degrees C, showing an excellent control of the catalyst stability under forced dynamic operational conditions.