Novel cake-like Fe–N–C hybrid for H2 activation

The activation and utilization of hydrogen energy is an effective method to solve the global energy crisis and environmental pollution. Herein, biomass-derived Fe–N–C catalysts for H2 activation were synthesized via the imitation of sponge cake baking. The sample pyrolyzed at 500 °C (Fe–N–C-500) presented the well-defined cake-like architecture with uniform distribution of Fe3O4 nanoparticles (NPs). Doping N species dispersed around metallic NPs in high density. Fe–N–C-500 exhibited excellent performance in the catalytic hydrogenation of nitrobenzene. The activity of Fe–N–C-500 depended on Fe3O4 NPs and pyridinic N, rather than Fe–N. The typical core-shell structure deemed vital for H2 activation in previous reports was not necessary. Notably, water could significantly promote the H2 activation, which might establish the communication between hydrogen molecules adsorbed on Fe3O4 NPs and doping N species through hydrogen bonds. Moreover, low temperature pyrolytic Fe–N–C-500 exhibited excellent stability and provided a promising potential for selective hydrogenation of nitroarenes or alkyne by regulating the reaction condition. This work provides an innovative approach to construct heterogeneous catalysts for H2 activation.