▎ 摘 要
The high aspect-ratio morphology of two-dimensional (2D) nanostructures endues them with distinct advantages for photocatalytic or photoelectrical applications. Although various attempts have been devoted to the liquid exfoliation of graphitic carbon nitride (g-C3N4) to obtain ultrathin nanosheets (CNNSs), the high exfoliation efficiency, well preservation of in-planar structure and facile operation cannot be simultaneously realized. Furthermore, functionalization of CNNSs is highly desired to promote the capability of photoabsorption, charge separation and transfer. Herein, we one-step prepared well-dispersed graphene quantum dots (GQDs)-modified CNNSs (GQDs/CNNSs) colloids via a facile and efficient GQDs-assisted exfoliation approach in a normal ultrasonic water bath. The exfoliation procedure was optimized by tuning the dopant in GQDs, ultrasonic time and GQDs dosage. The obtained colloidal GQDs/CNNSs show a typical 2D morphology with lateral size of several 100 nm and ultrathin thickness of 1.5-1.8 nm. What is more, we can tailor the semiconductive behavior of GQDs by heteroatom doping and achieve a p-n-type P-doped GQDs-modified CNNSs colloids. This p-n GQDs/CNNSs material presents the enhanced separation efficiency of photoexcited carriers and photocatalytic activity in comparison with bulky g-C3N4 (CN) and other CNNSs materials from acid or alkali exfoliation.