Scalable one-step template-free synthesis of ultralight edge-functionalized g-C3N4 nanosheets with enhanced visible light photocatalytic performance.

• Ultralight g-C 3 N 4 nanosheets have been synthesized via a facile and green one-step approach. • UMCN-wet shows a high surface area, enriched active sites and foam-like characteristics. • Fast charge separation with slow decay kinetics enhances the photocatalytic activity. • UMCN-wet exhibits high adsorption and photodegradation performance towards dye pollutants. Herein, we report a scalable, green and "bottom-up" approach for the synthesis of ultralight g-C 3 N 4 nanosheets. The ultralight g-C 3 N 4 nanosheets (9.6 mg cm−3) have been entirely synthesized in a wet atmosphere in one step without pretreatment or any other additives. The as-prepared material (UMCN-wet) appears as a foam-like exterior with ultrathin nanosheets (3.5 nm), short-order polymerization and sharp edges. The X-ray diffraction (XRD), Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) analyses confirm the formation of melon units with edge-enriched active sites. UMCN-wet exhibits a higher specific surface area (137.44 m2 g−1) and pore volume (0.2076 cm3 g−1), compared with that of the as-synthesized materials in the air (MCN-air) and nitrogen (MCN-N 2) atmospheres. The optical and electrochemical analyses reveal that UMCN-wet manifests fast photogenerated charge separation and transfer with slow decay kinetics. As a result, UMCN-wet nanosheets exhibit superb photocatalytic degradation of rhodamine B (RhB), methylene blue (MB) and methyl orange (MO) under visible light irradiation with photodegradation rate constant (k) of 0.17687, 0.02409 and 0.00537 min−1, respectively. Moreover, UMCN-wet exhibits excellent stability and reusability performance. Such a sustainable approach does not only overcome the prolonged time processing, extra energy consumption and utilization of hazardous chemicals for synthesis ultrathin g-C 3 N 4 nanosheets, but also paves a new pathway for industrial upscale production with numerous expected environmental applications. [ABSTRACT FROM AUTHOR]