This paper presents the engineering of a polyimide aerogel photocatalyst with photoreductive carbonyl groups for efficient and non-sacrificial H₂O₂ production. Under photoexcitation, surface carbonyl groups are reduced, forming an anion radical intermediate which is then oxidized by O₂ to produce H₂O₂, restoring the carbonyl group. This photocatalytic redox cycle enhances oxygen adsorption and lowers the energy barrier for H₂O₂ generation, achieving a 14.28% apparent quantum yield at 420 nm and a 0.92% solar-to-chemical conversion efficiency. A 0.5 m² aerogel exposed to sunlight for 6 hours produced 34.3 mmol m⁻² of H₂O₂.
