Atomic single layer graphitic-C₃N₄: fabrication and its high photocatalytic performance under visible light irradiation

Solar energy is ideal for photocatalytic degradation of pollutants. For efficient utilization of solar energy, the development of a high-activity and low-cost visible light driven photocatalyst is desired. Here we report a new type of atomic single layer graphitic-C3N4 (SL g-C3N4) as a high-performance photocatalyst for pollutant degradation under visible light (λ > 400 nm) irradiation. This SL g-C3N4 with thickness of 0.4–0.5 nm was prepared by an ultrasonic exfoliating process employing few layer graphitic-C3N4 nanosheets (g-C3N4 NS) as precursors. As a result of this atomic single layer, prolonged photogenerated charge lifetime and improved charge transfer capability were confirmed by time-resolved fluorescence emission spectra and electrochemical measurements, respectively. During the photocatalytic process under visible light irradiation, the degradation rate of rhodamine B on SL g-C3N4 was about 3.0 and 10.2 times higher than that of the few layer g-C3N4 NS and the bulk g-C3N4, respectively. This high photocatalytic performance is attributed to the atomic single layer structure of SL g-C3N4, which lengthens the lifetime of photogenerated charges and serves as an excellent electron transporter. The excellent performance achieved in this work suggests very appealing applications of SL g-C3N4 in many areas, such as photocatalytic degradation of environmental pollutants, solar cell, photocatalytic water splitting and electronic nanodevices.