Preparation of multi-defect state photo-responsive N-GQDs/CuS/Cv-CNNs materials and study of their properties

The imperative detection and elimination of hexavalent Cr(VI), a potent environmental pollutant and living organism hazard, is paramount for ecological conservation. The precipitation technique and charge action principles were used in this work to synthesis a cost-effective multi-defect nitrogen-doped graphene quantum dots/copper sulfide/carbon nitride composite photo-responsive materials (N-GQDs/CuS/Cv-CNNs, N-GCC) with good performance. To improve Cr(VI) detection and removal efficiency, multiple-point defects were generated to optimize the material's electrical structure and photo-responsivity. The multi-point defects were proved to greatly improve the light absorption of N-GCC, photosensitivity and consequently, the recognition rate of Cr(VI). The electron-rich multi-point defect structure accelerated the electrostatic adsorption and photoreduction of Cr(VI), which made the rapid removal of high Cr(VI) concentration possible, and it could remove 95.76 % of 120 mg/L Cr(VI) in 50 min with the specific surface area of N-GCC of 28.81 m²/g only. This study reveals the great potential of multi-point defect structures in treating Cr(VI) heavy metal pollution and opens up a new pathway for the remediation of chromium-contaminated environments.