A “Trojan horse” strategy towards robust Co–N4 active sites accommodated in micropore defect-rich carbon nanosheets for boosting selective hydrogenation of nitroarenes

Abstract

Selective hydrogenation of nitroarenes to corresponding anilines is one of the most important processes in the chemical industry, which still suffers from lack of efficient catalysts with both high activity and selectivity. Herein, a reinforced single-atom Co catalyst (Co–N–CNS–Th) was rationally fabricated through a novel “Trojan horse” strategy for boosting selective hydrogenation of nitroarenes. The cobalt salt precursor is confined in a mixed molten salt (KCl + CaCl₂) via recrystallization and gradually released when reaching the melting point, which can efficiently achieve atomic Co–N₄ moieties accommodated in micropore defect-rich carbon nanosheets. The prepared Co–N–CNS–Th catalyst showed superior hydrogenation activity and selectivity (yield of >99%; overall TOF of 169.8 h⁻¹) towards a series of functionalized nitroarenes under mild reaction conditions, as well as remarkable stability and reusability, standing out among the reported cobalt-based catalysts. The experimental results and DFT calculations reveal that the robust atomically dispersed Co–N₄ active sites located near the edge of micropore defects can significantly accelerate the adsorption and activation of hydrogen and nitro groups, accounting for the prominent catalytic performance. This work opens a feasible avenue for the development of advanced single-atom catalysts towards selective hydrogenation of nitroarenes and beyond.