Electrocatalytic conversion of SO2 into high-value ferric persulfate and H2O2

Sulfur dioxide (SO 2 ) is a harmful pollutant present in flue gas , necessitating urgent mitigation efforts. Converting SO 2 to persulfate represents an attractive approach; however, low generation selectivity in producing persulfate from alkaline-absorbed SO 2 presents a significant obstacle. Herein, we propose a novel Fe(III) oxidation-mediated SO 2 conversion strategy for the simultaneous electrochemical synthesis of high-value ferric persulfate (FPS) and hydrogen peroxide (H 2 O 2 ), offering a triple-function strategy. Initially, SO 2 is captured by cost-effective and abundant Fe(III), then routed to FPS via electrocatalytic oxidation to sulfate radicals (SO 4 • − ) on a boron-doped diamond anode. Simultaneously, H 2 O 2 is produced on a ZrO 2 /CMK-3 cathode. As demonstrated, the S 2 O 8 2- yield (23.8 mg·cm −2 ·h −1 ) and H 2 O 2 yield (11.7 mg·cm −2 ·h −1 ) exhibit dual high-efficiency performance, substantially exceeding that of most other reported single synthesis systems, respectively. In-situ Raman and theoretical calculations reveal that the HSO 4 − pathway is the primary kinetic route for persulfate generation. Moreover, the FPS product demonstrates exceptional removal of recalcitrant organics due to the synergistic advanced oxidation of persulfate and flocculation of Fe(III). This work offers a promising and sustainable solution for the resource conversion of SO 2 exhaust and simultaneous hydrogen peroxide production.