Isolated iron sites embedded in graphitic carbon nitride (g-C3N4) for efficient oxidative desulfurization

Iron-based catalysts are promising for the catalytic oxidation of H2S owing to their non-toxicity, abundance, and high conversion efficiency. However, their industrial applications are hampered by the low selectivity and poor durability. Herein, we reported a simple one-step pyrolysis approach to synthesize isolated Fe-N chi sites confined in graphitic carbon nitride (Fe-CN-NH chi). The creation of isolated Fe-N chi sites was evidenced by aberrationcorrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), X-ray absorption spectroscopy (XAS), UV-vis-NIR diffuse reflectance spectroscopy (DRS), and X-ray photoelectron spectroscopy (XPS). The well dispersed Fe-N chi sites offer additional active centers for the reaction, and such form of Fe presence effectively resists the deep oxidation of H2S. As a result, the obtained Fe-CN-NH5 catalyst exhibited outstanding catalytic performance with high sulfur selectivity. Significantly, the Fe-N chi sites are resistance to sulfur poisoning, leading to excellent durability in the reaction. No obvious decrease of catalytic activity was observed in a reaction period of 180 h, which is better than those of reported iron-based catalysts.