A gas bubble exfoliation method to prepare g-C3N4 nanosheets with enhanced photocatalytic activities

The exotic physicochemical properties of graphitic carbon nitride (g-C3N4) make it widely investigated and applied in photocatalysis. However, its low specific surface area, limited active sites and fast electron-hole pair recombination rate limit its further application. In this work, g-C3N4 nanosheets (CNNs) were fabricated by a simple and convenient gas bubble exfoliation method. To the best of our knowledge, this is the first time that bulk g-C3N4 (b-CN) was exfoliated by the generation and expansion of gas bubbles obtained from the electrolysis of water, which provides essential and dominant driving force to overcome the interlayer van der Waals force of b-CN, and achieve the exfoliation. The thin layer structure of CNNs was verified by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM). The surface area of CNNs was about 2.57 times that of b-CN. In addition, the photocatalytic performance of CNNs was proved by the degradation of methylene blue (MB) under visible light irradiation. Thus, gas bubble exfoliation is a new strategy to improve the photocatalytic performance of b-CN.