Eutectic solvent mediated synthesis of carbonated CoFe-LDH nanorods: The effect of interlayer anion (Cl-, SO42-, CO32-) variants for comparing the bifunctional electrochemical sensing application.

ABSTRACT

The unabated usage of priority anthropogenic stressors is a serious concern in the global environmental context. Pharmaceutical drugs such as furazolidone (FL) and nilutamide (NL) have far-reaching repercussions due to the presence of the reactive nitroaromatic moiety. Despite the widespread awareness regarding the dangers posed by nitroaromatic drugs, the promises to alleviate the environmental consequences of drug pollution are often unmet. Accordingly, implementing practices to monitor their presence in various media is a highly desirable, but challenging undertaking. With the advent of deep eutectic solvent-assisted synthesis, it has become possible to fabricate LDH-based sensor materials with minimal energy inputs in a sustainable and scalable manner. In this work, we have framed a series of CoFe-LDH electrocatalysts utilizing deep eutectic solvent-assisted hydrothermal strategies for the simultaneous detection of FL and NL. The CoFe-LDHs intercalated with three distinct anions, namely, (i) Cl-, (ii) SO42-, and (iii) CO32- are compared so as to establish a relationship between anion intercalation and electrochemical activity. Amongst the prepared electrodes, the CF-LDH-ii/SPCE displays highly appreciable selectivity, linear response range (0.09-237.9 µM), low detetion limits (FL = 1.2 nM and NL = 3.8 nM), high sensitivity (FL = 29.71 µA µM⁻1 cm⁻2 and NL = 19.29 µA µM⁻1 cm⁻2), good reproducibility and repeatability towards FL and NL in water and urine samples. Thus, with tailored gallery anions, the proposed electrocatalyst establishes enhanced electrocatalytic performance for the real-time analysis of pharmaceutical contaminants.