Aqueous-Phase Reduction of Nitrobenzene Enabled by a Symmetry-Disrupted Fe Single-Atom Catalyst Featuring Phosphorus Coordination

The selective reduction of nitroarenes to arylamines is a fundamental transformation in synthetic chemistry, yet it typically relies on harsh conditions, including elevated temperatures, pressurized H₂, noble metal catalysts, and organic solvents. Developing non-noble metal catalysts that deliver high efficiency and selectivity in environmentally friendly solvents remains highly desirable but challenging. We report a robust and easily prepared Fe-N/P-C single-atom catalyst, based on earth-abundant iron, which exhibits an outstanding reaction rate for the selective reduction of nitroarenes in water, enabled by an asymmetrically coordinated Fe center. It effectively facilitates the dissociation of N-H bonds in hydrazine, the rate-determining step that typically retards the fast action of hydrazine in various reduction processes, thereby promoting an electron-driven reduction pathway for the hydrogenation processes. Consequently, the reusable and sustainable Fe-N/P-C catalyst delivers previously unattainable turnover frequencies, even in large-scale reactions, while the normalized production rate stands an order of magnitude above the state of the art.