Iodide-Induced Fragmentation of Polymerized Hydrophilic Carbon Nitride for High-Performance Quasi-Homogeneous Photocatalytic H O Production.

Polymeric carbon nitride (PCN) as a class of two-electron oxygen reduction reaction (2 e ORR) photocatalyst has attracted much attention for H O production. However, the low activity and inferior selectivity of 2 e ORR greatly restrict the H O production efficiency. Herein, we develop a new strategy to synthesize hydrophilic, fragmented PCN photocatalyst by the terminating polymerization (TP-PCN) effect of iodide ions. The obtained TP-PCN with abundant edge active sites (AEASs), which can form quasi-homogeneous photocatalytic system, exhibits superior H O generation rate (3265.4 μM h ), far surpassing PCN and other PCN-based photocatalysts. DFT calculations further indicate that TP-PCN is more favorable for electron transiting from β spin-orbital to the π* orbitals of O , which optimizes O activation and reduces the energy barrier of H O formation. This work provides a new concept for designing functional photocatalysts and understanding the mechanism of O activation in ORR for H O production.