High-yield preparation of g-C₃N₄ nanosheet suspension by a two-step mechanochemical technique

Abstract Compared with the bulk g-C 3 N 4 , g-C 3 N 4 nanosheets have the advantages such as larger specific surface area and more active sites, making them more promising in optoelectronic applications. However, the current methods for preparing g-C 3 N 4 nanosheets have some disadvantages such as low yield, long exfoliation time and high energy consumption. Herein, a two-step mechanochemical method combining wet ball milling with ultrasonic-ball milling has been proposed, with a high yield of up to 31.8% for suspensible g-C 3 N 4 nanosheets. Adding YSZ balls during the ultrasound process can effectively improve the cutting efficiency of the g-C 3 N 4 sheets, thereby increasing the yield of the suspensible nanosheets. The stability of g-C 3 N 4 suspensions were relatively high, and the concentration of the suspensions remained above 87% after standing 24 h. The spectra of the nanosheets obtained through the two-step process had a single emission peak of 435 nm, which was suitable for photoluminescence detection.