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 mu mol-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. (C) 2018 Elsevier B.V. All rights reserved.