Highly Effective Denitrification by Activating Vaporized H₂O₂ over anti-SO₂ LaBO₃ (B = Fe, Ni, Mn) Perovskite Catalysts

Heterogeneous Fenton denitrification technology faces significant challenges, including low utilization efficiency of hydrogen peroxide (H2O2), limited catalyst stability, and insufficient tolerance to SO2. Thus, in this study, anti-SO2 La-based perovskite catalysts with different B-site elements (LaBO3, B = Fe, Ni, and Mn) were developed and compared to activate vaporized H2O2 for NO removal in flue gas. Both LaFeO3 and LaNiO3 exhibited superior catalytic performance, stability and SO2 resistance, whereas LaMnO3 demonstrated no catalytic activity. Under optimal experimental conditions, denitrification efficiencies of 98.3% for the LaFeO3/H2O2 system and 96.4% for the LaNiO3/H2O2 system, along with 100% desulfurization efficiencies for both systems, were achieved at a high GHSV, with a low molar ratio of H2O2 to NO (5:1). Hydroxyl radicals (•OH) and superoxide radicals (•O2–) were the primary reactive oxygen species (ROS) for oxidizing NO. The primary nitrogen-containing products derived from NO were NO2– and NO3–. The surface-accelerated circulation of Fe(II)/Fe(III) pairs in LaFeO3 and dispersed Ni(II)/Ni(III) pairs along with the electron-rich centers in LaNiO3 significantly contributed to the highly effective catalysis of H2O2.