Fe3C confined in N-doped carbons derived from Fe-N bearing ionic liquids for selective oxidation of styrene into benzaldehyde with molecular oxygen

It is of great significance but still a challenge in the chemical industry to develop high-efficient heterogeneous catalysts for selective oxidation of styrene into benzaldehyde with molecular oxygen. Fe3C nanoparticles confined in N-doped carbons (Fe3C/NC) were prepared using Fe3+ coordinated N-bearing ionic liquids as precursors and melamine as nitrogen source and template, followed by pyrolysis at 900 °C under N2 atmosphere. The physicochemical properties of the as-prepared Fe3C/NC catalyst were analyzed by FT-IR, TG, BET, TEM, XRD, Raman and XPS, respectively, and further employed as novel heterogeneous catalyst for selective oxidation of styrene into benzaldehyde with molecular oxygen. The results showed that the Fe3C nanoparticles were formed and uniformly embedded into the N-doped carbon matrix, which were confirmed to be the active sites for styrene oxidation. Moreover, the 5 % Fe3C/NC catalyst possessed high surface area and dominant mesoporous structure, which could expose more accessible active sites and facilitate mass transfer. As a result, the 5 % Fe3C/NC catalyst exhibited superior catalytic performance for styrene oxidation into benzaldehyde with the appropriate styrene conversion of 58.8 % and selectivity to benzaldehyde of 64.1 % as well as no significant activity and selectivity loss after reused at least five times.