As shown in Fig. S1, the experiments were conducted on a fixedbed system, which consisted of the generation of simulated flue gas, the H2O2atomization, the oxidation of NO and SO2 and the detection and absorption of oxidation products. The total flow was 250 mL/min and the simulated flue gases were supplied by compressed gas cylinders filled with NO, SO2 and N2, which were metered through a mass flow controller and mixed in buffer bottle. The atomized H2O2 was produced by a self-made ultrasonic H2O2 atomizer and carried into the reaction tube by N2.