Dual Cocatalysts Synergistically Promote Perylene Diimide Polymer Charge Transfer for Enhanced Photocatalytic Water Oxidation

Water oxidation is a critical reaction in artificial photosynthesis which is limited by a high reaction energy barrier and often requires matching cocatalysts. Dual cocatalysts Co3O4 and Pt are combined with a perylene diimide (PDI) polymer, accomplishing a photocatalytic O2 production rate of 24.4 mmol g–1 h–1 under visible light irradiation, which is a 5.4-fold enhancement compared with PDI alone. Moreover, the apparent quantum yield of the O2 evolution reaction reaches 6.9% at 420 nm and remains 1.2% at 590 nm. The dual cocatalysts-constructed interfacial electric fields provide an anisotropic driving force for photogenerated holes to Co3O4 and electrons to Pt, synergistically improving the spatial charge separation efficiency for water oxidation. Co3O4 molecules serve as active sites for the water oxidation reaction to improve the utilization of photogenerated holes on the surface. This work provides a valuable demonstration of the interaction process and mechanism of cocatalysts, guiding the selection of cocatalysts for high-efficiency solar energy conversion.