Defect-engineered activated bimetallic MOFs on laser-induced graphene for enhanced NO2 sensing

Abstract

With the acceleration of global urbanization, the efficient monitoring of nitrogen dioxide (NO2), a harmful pollutant linked to respiratory and cardiovascular diseases, has become increasingly critical. However, real-time detection of NO2 remains challenging due to limited response, slow response, and poor recovery characteristics. Here, we report a flexible and high-performance NO2 sensor based on Fe-doped MOF-5, synthesized via post-synthetic modification (PSM) and transmetalation for precise Fe integration. Laser-induced graphene (LIG) is employed as a conductive and mechanically flexible substrate, significantly enhancing gas sensing performance. The resulting LIG@bimetallic MOF hybrid exhibits a hierarchical porous structure, promoting rapid gas diffusion and high analyte accessibility. As a result, the sensor achieves ultrafast and highly sensitive NO2 detection at room temperature, with one of the fastest response times and lowest detection limits reported to date. The synergistic combination of MOF engineering and LIG integration provides mechanical flexibility, microscale patternability, and robust sensing performance, offering a promising platform for next-generation wearable and environmental gas sensors.