The carbon dioxide methanation reaction is highly exothermal (Delta(r)H298K(0) = -165 kJ mol(-1)) and needs therefore an efficient process to evacuate the heat generated during the reaction. In this paper, a structured bed filled with an open cell foam was chosen due to the many advantages of this kind of reactor (high surface/volume ratio, low pressure drop, intensification of mass and heat transfer...). First we showed that the presence carbon nanofibers didn't have an influence on the hydrodynamic behaviour of the platelet milli-reactor. Then, we used in situ infrared thermography to measure the surface temperature of the catalytic foam during the methanation reaction. The thermal imaging allowed us to visualize the "ignition" of the reaction, as well as to show the presence or absence of hot spots and their temperature. In this paper, we directly show for the first time the positive effect of carbon nanofibers on the surface temperature of the catalytic foam. (C) 2018 Elsevier Ltd. All rights reserved.