Asymmetric Oxygen Vacancy-Promoted Synthesis of Aminoarenes from Nitroarenes Using Waste H2S as a “Hydrogen Donor”

Abstract

The conversion of H₂S to high-value-added products is appealing for alleviating environmental pollution and realizing resource utilization. Herein, we report the reduction of nitrobenzene to aniline using waste H₂S as a “hydrogen donor” over the catalyst of FeCeO_2−δ with abundant oxygen vacancies (Ov), especially an asymmetric oxygen vacancy (ASOv). The electron-rich nature of the ASOv sites facilitates electron transfer to the electron-deficient nitro group, promoting the adsorption and activation of Ph–NO₂ through the elongation and cleavage of the N–O bond. Benefiting from the formation of abundant ASOv sites, the resulting FeCeO_2−δ achieves an impressive 85.6% Ph–NO₂ conversion and 81.9% Ph–NH₂ selectivity at 1.5 MPa and 90 °C, which surpasses that of pure CeO₂ with flower and rod morphologies. In situ FT-IR measurements combined with density functional theory calculations have elucidated a plausible reaction mechanism and a rate-limiting step in the hydrogenation of Ph–NO₂ by H₂S.