Ultrasonic synthesis of bismuth-organic framework intercalated carbon nanofibers: A dual electrocatalyst for trace-level monitoring of nitro hazards

Abstract

Environmental nitro hazards (NO2− and NO) are important contaminants in food and aquatic environments. Consumption of excessive nitro hazards can trigger a bio-oxidation reaction between hemoglobin (Fe2+) and methemoglobin (Fe3+) through an irreversible mechanism and restrict oxygen transport, which can lead to death. Therefore, the quantitative determination of nitro hazards is essential. The present study describes the quantitative determination of NO2− and NO using Bi-MOF intercalated carbon nanofibers (CNFs). The CNFs-Bi-MOF nanocomposite was prepared by a simple and effective ultrasonic synthetic route. The synthesized nanocomposite was evaluated using various spectral and microscopic techniques. FE-SEM and TEM results revealed the biphenyl-4,4′-dicarboxylic acid MOF (Bi-MOF) with an irregular rod-like structure. The composite showed intensely incorporated Bi-MOF with CNFs. The XPS result strongly confirmed that the oxidation state of the framework metal site was Bi3+. The composite modified on the GCE and then used for electrocatalytic oxidation of NO2− and NO. The CNFs-Bi-MOF/GCE exhibited excellent electrocatalytic activity with minimized overpotential for the oxidation of NO2− and NO. The CNFs-Bi-MOF/GCE displayed a wide linear range from 2 nM – 2 mM and 10 nM – 1 mM with LODs of 0.184 nM and 3.463 nM for NO2− and NO, respectively. Finally, the method was used in environmental effluent and tap water samples for the quantitative determination of nitro hazards.