Iodide-Induced Fragmentation of Polymerized Hydrophilic Carbon Nitride for High-Performance Quasi-Homogeneous Photocatalytic H2O2 Production

摘要

Polymeric carbon nitride (PCN) as a class of two-electron oxygen reduction reaction (2 e(-) ORR) photocatalyst has attracted much attention for H2O2 production. However, the low activity and inferior selectivity of 2 e(-) ORR greatly restrict the H2O2 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 H2O2 generation rate (3265.4 mu M h(-1)), far surpassing PCN and other PCN-based photocatalysts. DFT calculations further indicate that TP-PCN is more favorable for electron transiting from beta spin-orbital to the pi* orbitals of O-2, which optimizes O-2 activation and reduces the energy barrier of H2O2 formation. This work provides a new concept for designing functional photocatalysts and understanding the mechanism of O-2 activation in ORR for H2O2 production.