Magnetic field-enhanced catalytic CO2 hydrogenation and selective conversion to light hydrocarbons over Fe/MCM-41 catalysts

Abstract

Based on green and efficient utilization concepts, an external magnetic field is applied with an attempt to improve the catalytic performance in CO2 hydrogenation reaction. In this research, effects of magnetic field orientation and magnetic flux density on activity and selectivity of xFe/MCM-41 catalysts with ferro/ferrimagnetic property were investigated. With external magnetic field, especially in north-to-south (N-S) direction, CO2 conversions were significantly improved by 1.5–1.8 times; meanwhile, the activation energy was decreased by 1.12–1.15 times, compared to those of without magnetic field. Upon changing the magnetic flux density, CO2 conversion increased with increasing the magnetic flux density followed the order of 27.7mT>25.1mT>20.8mT. Furthermore, higher selectivities to C2-C3 hydrocarbons (2.5–5.3 times), and CH3OH (1.6 times) were observed at 180–200°C and 220°C, respectively. Among all the conditions with magnetic field, the highest CO2 conversion and selectivity to CH3OH and C2-C3 hydrocarbons were obtained at −27.7mT in N-S direction. These outstanding catalytic activities could be attributed to the fact that magnetic field help facilitate the reactant adsorption and surface reaction over the magnetized Fe catalysts, leading to the decrease of apparent activation energy, and also the increase of selectivities to hydrocarbons and CH3OH.