A polyimide aerogel catalyst with photoreductive carbonyl groups was developed to efficiently produce hydrogen peroxide (H₂O₂) through a photocatalytic redox cycle. The catalyst, named PI-BD-TPB, utilizes anion radical intermediates formed by the reduction of carbonyl groups on its surface. These radicals are then oxidized by oxygen to produce H₂O₂, which is subsequently converted back to the original carbonyl groups, completing the cycle. This process enhances oxygen adsorption and lowers the energy barrier for oxygen reduction, significantly improving the efficiency of H₂O₂ production. The catalyst achieved an apparent quantum yield (AQY) of 14.28% at 420 nm and a solar-to-chemical conversion efficiency of 0.92%. A 0.5 m² self-supported PI-BD-TPB aerogel produced 34.3 mmol m⁻² of H₂O₂ under natural sunlight. The study demonstrates the effectiveness of the redox cycle mediated by anion radicals in enhancing H₂O₂ production, offering a promising approach for sustainable and environmentally friendly hydrogen peroxide synthesis.A polyimide aerogel catalyst with photoreductive carbonyl groups was developed to efficiently produce hydrogen peroxide (H₂O₂) through a photocatalytic redox cycle. The catalyst, named PI-BD-TPB, utilizes anion radical intermediates formed by the reduction of carbonyl groups on its surface. These radicals are then oxidized by oxygen to produce H₂O₂, which is subsequently converted back to the original carbonyl groups, completing the cycle. This process enhances oxygen adsorption and lowers the energy barrier for oxygen reduction, significantly improving the efficiency of H₂O₂ production. The catalyst achieved an apparent quantum yield (AQY) of 14.28% at 420 nm and a solar-to-chemical conversion efficiency of 0.92%. A 0.5 m² self-supported PI-BD-TPB aerogel produced 34.3 mmol m⁻² of H₂O₂ under natural sunlight. The study demonstrates the effectiveness of the redox cycle mediated by anion radicals in enhancing H₂O₂ production, offering a promising approach for sustainable and environmentally friendly hydrogen peroxide synthesis.