Graphite Felt-Sandwiched Ni/SiC Catalysts for the Induction Versus Joule-Heated Sabatier Reaction: Assessing the Catalyst Temperature at the Nanoscale

The paper describes a series of graphite felt-sandwiched ^kNi/SiC composites at variable metal loading (k = 10, 15, and 20 wt %) and their application as catalysts for the CO₂ methanation process (Sabatier reaction) under two distinct and conceptually different heating setups: Joule heating versus induction heating (IH). A comparative analysis carried out on all catalysts from this series operated under the two heating configurations has unveiled the superior performance of radiofrequency (RF)-heated (IH) catalysts in the process. Most importantly, it has offered a practical tool to map the gap existing between the macroscopic temperature value measured at the catalyst bed using a remote-sensing thermometer (pyrometer) and that (real) of the excited metal nano-objects (Ni NPs) directly engaged in the RF-heated catalytic process. Besides the evident advantages of IH technology applied to the methanation process in terms of process rates (λ) already under nominally low reaction temperatures, the virtual absence of any thermal inertia and the subsequent fast modulation of the temperature at the catalytic bed demonstrate unique features of this heating technology in terms of process safety (cold-reactor walls) and reduction of energy wastes (neither pre- and postcatalyst heating of reagents and products nor that of the whole reactor volume and its peripheral walls).