Efficient and selective H₂O₂ production through uranyl-assisted photocatalytic oxygen reduction reaction process in a uranium-organic framework

Harnessing solar energy by photocatalytically converting oxygen and water into high-value-added H₂O₂ is a promising way of alleviating both environmental and energy issues. It is worth noting that suppressing detrimental side reactions, such as the generation of •O₂⁻, is a critical approach to enhancing H₂O₂ production. Herein, a 2-fold interpenetrating 3D uranium-organic framework (YTU-W-1) was developed and introduced for photocatalytic H₂O₂ production. The material demonstrates a different photocatalytic mechanism when employing uranyl as an initiator, as compared with the conventional semiconductor photocatalytic pathway involving photo-generated charge carriers. Benefiting from the strong hydrogen abstraction effect of the U≡O^• and the direct one-step oxygen reduction pathway, YTU-W-1 exhibits enhanced photocatalytic performance for H₂O₂ production with yield efficiency of 221 µmol h⁻¹ g⁻¹. Furthermore, YTU-W-1 displays a high H₂O₂ selectivity of 68%, confirmed by rotating ring-disk electrode (RRDE) measurement. DFT calculations were used to elucidate the critical role of uranyl in the photocatalytic oxygen reduction reaction for H₂O₂ production. This research introduces an innovative approach to photo driven H₂O₂ production, underscoring the potential for heterogeneous catalysts to engage in photocatalytic reactions independently of photo-generated charge carriers.