Abstract
2D nanosheets of graphitic carbon nitride (g-C(3)N(4)) have emerged as promising metal-free photocatalyst. However, their reproducible preparation with a control of physiochemical properties is challenging, and the commonly used thermal polymerization method often leads to the formation of bulk g-C(3)N(4) with faster e(-)-h(+) recombination and low surface area, which hinder its full photocatalytic potential. To address these limitations and obtain highly exfoliated and mesoporous 2D nanosheets of g-C(3)N(4) (EmNs) with desirable physiochemical properties, we propose a facile and reproducible collaborative strategy, based on the synergistic use of ammonium salts as a dynamic gas template and oxidative exfoliation (OE). The prepared EmNs were characterized by an array of complementary analytical techniques including XRD, DRS, EPR, NMR, TEM, SEM-EDX, Raman Spectroscopy, LC-DAD-MS, and time-resolved photoluminescence (PL) measurements and their photoactivity was evaluated through photodegradation of rhodamine B (RhB) dye and 2,4-D herbicide as model pollutants. The proposed one-pot, two-steps thermochemical synthesis protocol not only leads to the preparation of thin (12 ± 3 nm) EmNs but also allows the tuning of their electronic structure, band gap, textural properties, nitrogen vacancies (N-vacancies), and photocatalytic response. Importantly, the band gap energy (E (g)), specific surface area, number of N-vacancies, and lifetimes of charge carriers (63-69 ns in EmNs vs 47 ns in pristine g-C(3)N(4)) were all found to increase with increasing NH(4)Cl/melamine ratio and after OE treatment in a synergistic manner. Resultantly, the prepared g-C(3)N(4) EmNs exhibited 4 times higher photoactivity (k (obs.) = 0.09 min(-1)) than pristine g-C(3)N(4) (k (obs.) = 0.023 min(-1)). This one-pot, two-step collaborative strategy can be used as an optimized protocol for the reproducible preparation of thin, highly photoactive, and mesoporous g-C(3)N(4) nanosheets with tailored and enhanced physicochemical properties for desired applications.