Controllable Preparation of Photosensitive Nanozymes Based on Metal–Organic Frameworks for Peroxidase-Mimicking Activities: Realizing Integrated Atrazine Visual Detection and Photocatalytic Degradation

Atrazine management in water environments typically requires two separate steps: detection and degradation. Furthermore, their integration is more beneficial because it allows for removal at the moment of discovery, preventing the spread of pollution and the need for complicated operating procedures. In this study, the photosensitive nanozyme MIL-125 (Ti/Fe)-1.0%-N2 was created to integrate the visual detection of atrazine and photocatalytic degradation through the alteration of hydroxyl generation under dark conditions or light irradiation. The increased visible light absorption, the decreased rate of photogenerated electron–hole recombination, and the favorable environment for electron transfer achieved through the modification of the NH2 functional group, the collaborative creation of Ti and Fe bimetals, and the calcination at a N2 atmosphere all work together to improve the photoresponse performance. As a result, it caused the transfer of long-lived photogenerated electrons and accelerated the Fe2+/Fe3+ redox cycle in the H2O2 catalytic conversion process. MIL-125 (Ti/Fe)-1.0%-N2 has a wide pH availability and recycling range, and it can perform the combined function of visual detection (1–50 μg/L) and effective degradation (1–100 mg/L) for atrazine. This is based on the dual-path mechanism of Fenton catalysis under dark conditions and electron transfer enhancement under light irradiation.