Deciphering the Controversial Role of Sacrificial Agents in Photocatalytic H₂O₂ Production: Promoters or Source of Artifacts?

Photocatalytic H2O2 synthesis holds great promise for sustainable H2O2 production. While extensive efforts have focused on optimizing catalysts and reaction conditions to enhance H2O2 yields, the accuracy of H2O2 quantification─a fundamental prerequisite for reliable performance evaluation─remains underexplored. Conventional colorimetric methods can be compromised by the widespread use of organic sacrificial agents due to their intrinsic redox activity and optical absorption properties. Herein, we systematically investigate the interference effects of common sacrificial agents and their oxidation products on H2O2 quantification across several established colorimetric assays. Our results reveal that quantification inaccuracies arise from a combination of factors, including pre-existing H2O2 contamination, spectral overlap, unintended redox reactions, and self-sensitization effects. Drawing from these findings, we propose practical guidelines for selecting compatible sacrificial agents, detection methods, and excitation wavelengths to minimize analytical artifacts and enable accurate evaluation of photocatalytic H2O2 production.