Surface Defects‐Induced Photoactivation of Carbon Dots‐NiFe<sub>2</sub>O<sub>4</sub> Nanocomposite: Synthesis, Mechanism and Applications
Ruyan Xie, Shuzhe Zhang, Yanhua Song, Xiaozhen Zhang, Shihou Sheng, Haifeng Zou
Abstract
Abstract The optical properties of quantum dots are significantly influenced by photoactivation. However, the progress in the development of photoactivation carbon dot (CDs) is still stagnant. Herein, a method for preparing photoactivated CDs/NiFe 2 O 4 by introducing affluent defects onto the surface of CDs through modification with NiFe 2 O 4 , extremely filling the gap of photoactivated CDs is proposed. Interestingly, a fantastic fluorescence detection strategy in a unique “OFF‐ON‐OFF” mode, combined with Ag + ‐assisted fluorescence enhancement, to establish a dual‐channel regulation mechanism for ultra‐sensitive detection of Hg 2+ is first proposed. By increasing surface traps and non‐radiative recombination, defect‐induced manipulation on the surface of CDs creates favorable conditions for enhancing photoactivation capacity. Unexpectedly, the CDs/NiFe 2 O 4 shows a 25‐fold enhancement in fluorescence intensity after exposure to UV‐lamp. Compared to CDs/NiFe 2 O 4 , Ag + ‐assisted photoactivation CDs/NiFe 2 O 4 exhibits superior selectivity and sensitivity for Hg 2+ detection, with low detection limits of 0.7 nM. Moreover, TiO 2 @CDs/NiFe 2 O 4 catalyst is successfully prepared by anchoring CDs/NiFe 2 O 4 onto the surface of TiO 2 , which demonstrates efficient degradation of tetracycline within 90 min under visible light irradiation, with a degradation rate of 98.3%. This work first provides a novel defects modification strategy for developing highly active photoactivated CDs technology that is significant for future environmentally sensitive applications.