Photocatalysis coupling hydrogen peroxide synthesis and in-situ radical transform for tetracycline degradation

• A novel nanorod-like C 3 N 4 photocatalyst with alkali modification is synthesized. • TC degradation system namely in-situ H 2 O 2 generation/radical transform is built up. • H 2 O 2 generation is enhanced by consuming hole based on adsorbed organic molecules. • Mechanism on TC degradation system employed C 3 N 4 photocatalyst is elucidated. Although much effort has been put into hydrogen peroxide (H 2 O 2 ) synthesis, multifunctional catalytic systems suitable for in-situ H 2 O 2 utilization in the field have rarely been investigated. In this study, carbon nitride nanorod (GCN-Rod) is designed to couple H 2 O 2 generating and activation for efficient environment remediation. The limitation of the sluggish hole oxidation kinetics during the photocatalytic H 2 O 2 production is overcome by oxidation of electrostatically adsorbed contaminant molecules. Acid-activated carbon nitride nanorod binds a large number of protons onto the surface, forming an acidic micro-environment prone to protonating organic molecules into positively charged molecules and adsorbed on the negative zeta-potential catalyst surface for oxidation reactions. The in situ synthesized H 2 O 2 is confirmed to be the origin of reactive oxygen species by EPR and band position analysis. The photocatalytic tetracycline (10 ppm) degradation ability approaches approximately 100 % within 10 min under visible-light irradiation. Cycle tests also demonstrated sufficient stability. This work achieves a delicate coupling of H 2 O 2 production and in-situ utilization, which is sufficient for continuous pollutant degradation, expanding the catalyst design methods.