An electrochemical sensing platform of cobalt oxide@SiO2/C mesoporous composite for the selective determination of hydrazine in environmental samples

Abstract

An electrochemical sensor was developed for hydrazine detection in wastewater. Cobalt oxide (Co3O4) nanoparticles were in-situ synthesized in the pores and distributed uniformly within the prepared mesoporous SiO2/C. The mesoporous composite has a high surface area (SBET 432.56 m2·g−1), a bigger volume of pores (0.89 cm3·g−1), and pore size of about 7–8 nm, evaluated by BET methodology. SEM images and the corresponding elemental mapping have shown no phase segregation at the applied magnification. The prepared composite Co3O4@SiO2/C was compressed in disk shape to make a working electrode for electrochemical hydrazine detection at pH 7. The limit of detection, the limit of quantification, linear response range, and sensitivity are 0.08 μM, 0.1x10−6 M, 10–1800 μM, and 430 μA·μM cm−2, respectively. The sensor response time in the presence of hydrazine at 100 μM is less than 2 s. The sensing probe exhibited chemical stability, high sensitivity, and negligible interference with other electroactive species found in river water and industrial effluents. The sensor's repeatability was measured as 1.97% (RSD; for n = 10 at 600 μM hydrazine level).