Graphitic Carbon Nitride Nanosheets Decorated with Strontium Tungstate Nanospheres as an Electrochemical Transducer for Sulfamethazine Sensing

Sulfamethazine (SMZ) is one of the most frequently utilized sulfonamides, and it is regularly found in animal-derived foods, posing a health risk. Hence, developing a quick, easy, selective, and sensitive analytical method for on-site detection of SMZ is essential for improving food safety. Recently, transition-metal oxides have attracted great interest as promising sensors for detecting sulfamethazine due to their superior redox behavior, electrochemical activity, and electroactive sites. However, they tremendously suffer from poor electrical conductivity and electrochemical stability, which limits their commercial reality. Herein, a highly selective sensor consisting of two-dimensional (2D) graphitic carbon nitride nanosheet (g-C3N4) networks anchored to strontium tungstate nanospheres (denoted as SrWO4/g-C3N4) is developed for nonenzymatic sulfamethazine detection. When employed as the sensing platform, the SrWO4/g-C3N4 hybrid shows enhanced sensing performance with a fast response time, high sensitivity, low detection limit of 0.0059 μM, wide detection ranges from 0.2 to 600 μM, and prolonged cycle life of over 30 days. The sensor performs well in sulfamethazine in real sample analysis, reflecting its practical applicability. Such a performance may be attributed to the numerous electroactive sites, confined electronic structures, and high synergistic interaction between active SrWO4 species and the g-C3N4 matrix. This work demonstrates an innovative protocol for developing SrWO4/g-C3N4-based sensing platforms with nanoscale architectures and high interface configurations.