Defects remodeling of g-C₃N₄ nanosheets by fluorine-containing solvothermal treatment to enhance their photocatalytic activities

Excessive or deficient defects in graphitic carbon nitride (g-C₃N₄) nanosheets are detrimental to their photocatalytic activities. In this work, the approach of fluorine-containing solvothermal treatment has been applied to remodel the defects in g-C₃N₄ nanosheets (CNS). The fabrication process has been comprehensively investigated and the samples are characterized by various techniques. The results manifest that the solvothermal treatment declines the amount of defects, while the addition of fluorine stimulates the emergence of nitrogen vacancies for producing new active sites which makes the obtained fluorine modified CNS present excellent photocatalytic activities. The average rate of photocatalytic hydrogen evolution under visible light irradiation is 2607.4 μmol·h⁻¹·g⁻¹, which is almost 13 and 1.3 times of bulk g-C₃N₄ (BCN) and CNS, respectively, and the degradation rate of rhodamine B is about 3.4 and 1.9 times, respectively.