Structural healing of deficient carbon nitride for efficient H2O2 photosynthesis

Abstract

Rational vacancy engineering endows semiconductors with exotic chemical and physical properties, particularly in photocatalysis. Herein, we report a KBr-mediated bulk vacancy repolymerization strategy for the structural engineering of polymeric carbon nitride (PCN), obtaining a modified catalyst (KCN) with optimized physicochemical properties. Structural characterizations reveal that KBr mediation not only heals bulk vacancies and reconstructs layered stacking but also introduces surface cyano groups and K⁺ ions into the framework, providing a favorable dynamic driving force for the photocatalytic oxygen reduction process. Therefore, KCN exhibits a remarkable H₂O₂ evolution rate of 5488 μmol g⁻¹ h⁻¹ (λ > 420 nm), which is about 140 fold higher than pristine PCN. This work provides a promising avenue for designing high-performance photocatalysts.