Remediation‐Driven Upcycling of Aqueous Pb Pollutants Into X‐Ray Detector Materials via a Nitrogen‐Doped MXene/Prussian Blue Heterostructure

ABSTRACT Bridging toxic metal remediation with high‐value materials manufacturing remains a major challenge for sustainable materials science. Here, we report a remediation‐driven upcycling strategy that directly converts aqueous Pb pollutants into an active material for X‐ray detection using a nitrogen‐doped MXene/CuFe Prussian blue heterostructure (NMPB). Nitrogen‐doped MXene serves as both a conductive scaffold and an interfacial coordination platform, enabling the uniform growth of CuFe‐Prussian blue nanocubes and enhanced electronic coupling within the hybrid framework. Upon exposure to Pb 2 + ‐containing water, the heterostructure captures and immobilizes Pb through a framework‐confined ion‐exchange process, delivering a high uptake capacity of 501.1 mg g − 1 together with excellent tolerance to acidic conditions. The resulting Pb‐loaded composite combines the strong X‐ray attenuation of heavy atoms with efficient charge transport through the conductive MXene network. As a direct‐conversion X‐ray detector, the recycled material achieves a sensitivity of 1.3 × 10 4 µC·Gy air −1 ·cm −2 and a detection limit of 42 nGy air ·s −1 , while maintaining stable operation after prolonged acid treatment. In addition, scalable spray coating enables large‐area and flexible device integration. This work establishes a route for transforming toxic metal pollutants into structurally robust functional materials, providing a general platform for waste‐to‐device upcycling.