Fe atom-substituted molybdenum carbide catalyst for the chemoselective hydrogenation of nitro compounds under mild conditions

In the quest for sustainable catalytic processes, non-noble metal catalysts offer a promising alternative for the selective hydrogenation of organic compounds. This work reports the design of a Fe-doped Mo₂C catalyst (Fe-Mo₂C@CN), featuring partial substitution of Mo atoms with Fe atoms, which exhibits remarkable catalytic performance in the chemoselective hydrogenation of nitro compounds. The Fe-Mo₂C@CN-700 catalyst achieves a turnover frequency (TOF) of 36.6 h⁻¹ at mild reaction conditions (80 °C and 1 MPa H₂), outperforming most non-noble metal catalysts reported under similar conditions. More notably, at near room temperature (30 °C and 1 bar H₂), it achieves high yields (≥93 %), making it competitive with noble metal catalysts. Studies reveal that Mo₂C serves as the primary active site for hydrogenation, and partial substitution of Mo atoms with atomically dispersed Fe not only modulates the adsorption strength but also induces a tilted adsorption configuration of the nitro group, thereby facilitating more efficient hydrogenation. Fe-Mo₂C@CN-700 delivers excellent yields (86–98 %) in the hydrogenation of a wide variety of functionalized nitroarenes to anilines, including sulfur-containing substrates and several high-value pharmaceutical nitroaromatics. The optimal Fe-doped Mo₂C catalyst can also maintain its activity for >18 h in a fixed-bed reactor, implying its promising industrial application.