Fluorine functionalized graphitic carbon nitride for cataluminescence sensing of H2S

[Display omitted] •Fluorine functionalized graphitic carbon nitride (F-g-C3N4) was successfully synthesized under mild and simple conditions.•F-g-C3N4-based CTL sensor exhibits lower LOD than metal-free-based sensors and equivalent sensitivity of metal-based sensors.•The CTL mechanism of H2S on F-g-C3N4 and the role of fluorine were deeply explored by experiments and DFT. Graphitic carbon nitride, as an excellent metal-free catalyst, is a promising candidate for cataluminescence (CTL) sensing of H2S owing to its high sulfur tolerance, environmental friendliness and low cost. Herein, in view of inner chemical inertness and low special surface area of g-C3N4, fluorine with strong electronegativity was employed to adjust the electron density of g-C3N4 to obtain fluorine functionalized graphitic carbon nitride (F-g-C3N4) for H2S sensing. As expected, the CTL response of F-g-C3N4 exhibits more than 30 times higher towards H2S by contrast with that of g-C3N4. Results demonstrated that F-g-C3N4 was more conducive to the adsorption of O2 and H2S due to the enlarged special surface area, the easier formation of hydrogen bond and the changed electronic structure, which was also supported by density functional theory calculations. Additionally, the F-g-C3N4-based sensor exhibits as high sensitivity as that of metal catalyst-based sensors but a longer lifetime. Meanwhile, the F-g-C3N4-based sensor has much higher CTL responses in the range of 1.27∼64.00 μg mL−1, lower detection limit of 0.07 μg mL−1 when comparing with previously reported metal-free catalyst-based sensors. Undoubtedly, this work not only opened up a novel approach to improve the sensing performance of g-C3N4, but also proposed an efficient strategy for obtaining satisfying catalytic performance of other metal-free layered materials.