g-C3N4
- Bulk g-C3N4 (BCN) : direct heating of 5 g dicyandiamide/melamine at 550 ºC in a furnace for 4 h in a semiclosed system. The resultant yellow agglomerates can be milled into powders in an agate mortar.
- g-C3N4 nanosheets (CNNs) : acidation and ultrasonication. 1.0 g of the finely-ground bulk g-C3N4 powders are added into 50 mL concentrated nitric acid, and then agitated for 4h. Then the mixture is centrifuged and washed repeatedly with distilled water till neutrality before being dried in an oven at 60 ºC for 12 h.
- 200 mg of the obtained powders are dispersed in 100 mL ethanol at room temperature and exfoliated by ultrasonication for 8 h. The resultant suspension is centrifuged at 3000 rpm for 20 min to remove the residual unexfoliated g-C3N4.
- The as-prepared CNNs are collected by centrifuging at 12,000 rpm for 30 min and dried at 60 ºC overnight.