Iodide‐Induced Fragmentation of Polymerized Hydrophilic Carbon Nitride for High‐Performance Quasi‐Homogeneous Photocatalytic H 2 O 2 Production

Abstract Polymeric carbon nitride (PCN) as a class of two‐electron oxygen reduction reaction (2 e − ORR) photocatalyst has attracted much attention for H 2 O 2 production. However, the low activity and inferior selectivity of 2 e − ORR greatly restrict the H 2 O 2 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 2 O 2 generation rate (3265.4 μM h −1 ), 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 2 , which optimizes O 2 activation and reduces the energy barrier of H 2 O 2 formation. This work provides a new concept for designing functional photocatalysts and understanding the mechanism of O 2 activation in ORR for H 2 O 2 production.