Highly Efficient Iron-Based Catalyst for Light-Driven Selective Hydrogenation of Nitroarenes

Light-driven hydrogenation of nitro compounds to functionalized amines is of great importance yet a challenge for practical applications, which calls for the development of high-performance, nonprecious photocatalysts and efficient catalytic systems. Herein, we report a high-efficiency Fe₃O₄@TiO₂ photocatalyst via a sol-gel and subsequent pyrolysis strategy, which exhibits desirable photothermal hydrogenation performance of nitro compounds to functionalized amines with the excellent selectivity of >90% exceeding those of the state-of-the-art heterogeneous photocatalysts. Our experimental results and theoretical calculations for the first time reveal that Fe₃O₄ is the major active phase, and the strong metal-support interaction between Fe₃O₄ and reducible TiO₂ further leads to performance improvement, taking advantage of the enhanced photothermal effect and the improved adsorption for the reactant and hydrazine hydrate. Notably, a variety of halonitrobenzenes and pharmaceutical intermediates can be completely converted to functionalized amines with high selectivities, even in gram-scale reactions. This work provides a new insight into the rational design of nonprecious photo/thermo-catalysts for other catalytic reactions.