One-pot preparation of potassium, iodine-codoped hydrophilic polymeric carbon nitride with highly efficient quasi-homogeneous photocatalytic H2O2 production

The production of hydrogen peroxide (H2O2) through visible photocatalytic molecular oxygen has gained significant attention as an environmentally friendly and sustainable approach. In this study, a unique multivariate modified graphitic carbon nitride (g-C3N4) photocatalyst is designed and successfully synthesized by incorporating K and I species as heteroatomic co-dopant, along with the defect engineering in g-C3N4. The resulting photocatalyst consists of particles ranging in size from 50 to 200 nm. Experimental results reveal that K atoms form chemical bonds with N atoms in adjacent layers, facilitating enhanced electron migration. On the other hand, I atoms predominantly localize at the edges of g-C3N4 building blocks, contributing to the formation of cyano groups (-C---N). These cyano groups, acting as nitrogen defects, can effectively narrow the band gap, elevate the conduction band, and effectively improve the generation and transport of photoexcited charge carriers. By precisely controlling the proportion of KI, the formation of cyanide can be effectively regulated. Notably, the obtained photocatalyst exhibits a remarkably high H2O2 yield of 4386.4 mu\M h-1 under visible light, surpassing that of g-C3N4 and other g-C3N4-based photocatalysts. This work presents a novel design strategy for the development of highly efficient photocatalysts for H2O2 production.