Bimetallic metal–organic framework derived Mn, N co-doped Co-Carbon for electrochemical detection of nitrite

Detection and control of nitrite are major concerns in recent years for ensuring food and environmental safety. In this study, Mn, N co-doped Co-Carbons (CoMnN-Cs) were synthesized by calcination of bimetallic Co-Mn zeolite-imidazolate framework (CoMnZIF-67) materials at different temperatures (600–900 °C) in nitrogen atmosphere. Many characterizations, such as scanning electron microscope (SEM), elemental mapping, and, N 2 adsorption–desorption were performed to analyze the morphology, structure, and composition of the CoMnN-Cs. SEM revealed the generation of rich carbon nanotubes (CNTs). Mn-doping was obtained, which could be seen from the elemental mapping. The characterization also revealed that the pyrolysis temperature has an important effect to catalytic activities. From obtained results, it was found that the CoMnN-Cs prepared at 800 °C (CoMnN-Cs-800), showed better detection performance compared with CoMnN-Cs developed at other temperatures. As a result, the CoMnN-Cs-800-based sensor manifested an extended linear range (from 0.2 to 7000 μM), a low detection limit of 0.16 μM, and high sensitivity. Meanwhile, the developed sensor exhibited good selectivity, reproducibility, and long-term stability. Moreover, the sensor achieved satisfactory recoveries for the quantification of nitrite in tap water and sausage samples. This study implies CoMnN-Cs-800 is a promising material for the measurement of nitrite. Graphical abstract