Nitrogen-Doped Graphitic Carbon Dots Embedded in Carbon Nitride Scaffolds for Water Decontamination

Abstract

Functionalized carbon dots (CDs) exhibit intriguing photo-exciton dynamics. CDs can donate or accept electrons depending on their functional groups and electrostatic characteristics. We exploited the electron-accepting capability of nitrogen-doped graphitic carbon dots (N-g-CDs) to improve the charge-carrier separation of the polymeric carbon nitride (PCN) photocatalyst. l-Aspartic acid pyrolyzed at 320 °C yielded ∼25 nm size N-g-CDs that were embedded with PCN. The in-plane infiltration of nanosized N-g-CDs increased the surface area of PCN from 11.5 to 104.9 m2 g–1. The N-g-CDs/PCN hybrid catalyst tested for photocatalytic chromium reduction evidenced about a 3-fold higher rate than PCN. Also, the antibiotic tetracycline and rhodamine B dye rapidly degraded with faster degradation kinetics. The carrier dynamic analysis and computational investigations suggest that the electron acceptor feature of N-g-CDs governs the effective separation of photo-excitons and the high surface area of N-g-CDs/PCN contributes to photoactivity enhancement. This study offers insights into designing high-performance metal-free photocatalysts for water treatment applications.