Engineering Iron-Nickel Nanoparticles for Magnetically-Induced CO2 Methanation in Continuous Flow

International audienceInduction heating of magnetic nanoparticles (NPs) has been recently explored as a new methodology to activate heterogeneous catalytic reactions. This approach requires the design and the synthesis of nano-objects displaying both a high heating power and an excellent catalytic activity. Here, using a surface engineering approach, we report for the first time the use of bimetallic NPs for magnetically-induced CO2 methanation which acts both as heating agent and as catalyst. Thus, we describe the organometallic synthesis of Fe30Ni70 NPs, displaying high heating powers at low magnetic field amplitudes. These NPs are active but only slightly selective for CH4 after deposition on SirAlOx due to the presence of an iron rich shell (25 mL·min-1 , 25 mT, 300 kHz, conversion 71%, methane selectivity 65%). Remarkably, a proper surface engineering consisting in depositing a thin Ni layer leads to Fe30Ni70@Ni NPs displaying a very high activity for CO2 hydrogenation and a full selectivity. For the first time, a quantitative yield in methane is obtained at low magnetic field and mild conditions (25 mL·min-1 , 19 mT, 300 kHz, conversion 100%, methane selectivity 100%)