MOF-74-inspired Metal-Organic Complex as an Efficient Peroxidase-Mimicking Electrocatalyst for Ultrasensitive Hydrogen Peroxide Sensing

Hydrogen peroxide (H₂O₂) is a widely used oxidizing agent in industrial processes, and a 3 wt% aqueous solution is commonly employed as a disinfectant. In this study, a metal–organic complex (DHTPN) was synthesized via a one-step coordination reaction between 2,5-dihydroxyterephthalic acid (DHTP) and NiCl₂. The resulting complex exhibits a fine-tuned lattice structure resembling MOF-74(Ni) and was comprehensively characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). When immobilized onto a glassy carbon electrode, the DHTPN-modified electrode functioned as an efficient electrochemical sensor for H₂O₂ detection. Under optimized conditions, the sensor exhibited a broad linear detection range from 10 μM to 13.32 mM and an ultralow detection limit of 3.3 μM. In addition, the device demonstrated excellent selectivity, reproducibility, and operational stability, along with a rapid response time of 3.5 s. Furthermore, the sensor was successfully applied to the quantitative analysis of commercial 3 wt% H₂O₂ disinfectant without any sample pretreatment, yielding accurate and reliable results. This work highlights the potential of metal–organic complexes as advanced electrode materials in electroanalytical chemistry and provides a promising platform for rapid, sensitive, and efficient H₂O₂ detection.