Carbon-Based Catalyst Derived from Cobalt Colloid for Mild Hydrogenation of Nitrobenzene

The efficient hydrogenation of nitroaromatics under mild conditions remains a significant challenge, particularly while retaining sensitive functional groups. Herein, we report a cobalt-based catalyst supported on nitrogen-doped carbon (10% Co@NC), which achieved 100% conversion and >99% selectivity in the hydrogenation of nitrobenzene at mild temperature (30 °C) and pressure (10 bar). The catalyst exhibited an exceptional space-time yield of up to 1.89 g·g_cat^-1·h^-1, surpassing most reported cobalt-based catalysts. The catalyst demonstrated remarkable stability for over 400 h. The outstanding performance originated from the synergistic effect between the nitrogen-doped carbon support and the metallic cobalt particles. Such efficient hydrogenation under ambient temperatures is exceedingly rare among non-noble metal-based catalysts. In situ DRIFTS experiments and Density Functional Theory (DFT) calculations revealed that the nitrogen vacancy (N_v) in the carbon matrix played a pivotal role by giving rise to the spontaneous hydrogenation of the nitro group, thereby enabling the high-performance catalysis under mild conditions.