Lattice Oxygen Activation Triggered by Ultrasonic Shock Significantly Improves NO Selective Catalytic Reduction

The precise regulation of lattice oxygen is crucial for many redox reactions, but it still remains a formidable challenge. Herein, we reported a facile strategy to induce generation of bulk phase defects in hematite (α-Fe2O3) by ultrasonic treatment, thus achieving exclusive lattice oxygen activation without additional alternation of surface adsorbed oxygen species. This kind of unique lattice oxygen activation afforded negligible disturbance of NH3 adsorption but significant influence on NO2 generation via accelerated oxygen diffusion, resulting in enhanced activity contribution from the Fast-SCR reaction pathway. Particularly, the generation of bulk-phase defects was also found to be conducive to create thermally instable and chemically reactive surface nitrate species, which played a decisive role in activating NO reactant. Accordingly, a triple increment in the deNOx performance of the α-Fe2O3 catalyst for the reaction of selective catalytic reduction of NO with NH3 (NH3–SCR) was achieved.