Ni–Fe layered double oxide on porous nickel foam: a rationalized approach to electrochemical sensing of Atrazine herbicide in water samples

Abstract

An easy and ultrasensitive detection approach is highly in demand considering the detrimental environmental and health effects of atrazine, a class 3a carcinogen. This work demonstrates the facile and label-free electrochemical detection of atrazine. The physicochemical and electrochemical characterization confirmed the successful preparation of Ni–Fe LDO. The layered morphologies of both pristine layered double hydroxide (LDH) and LDH-derived layered double oxide (LDO) are confirmed via scanning electron microscopy (SEM) analysis. The 3D porous network structure of nickel foam (NF) accommodates more electrocatalyst on its surface due to its high surface area. Powder X-ray diffraction (PXRD) reveals the crystallinity and Raman spectroscopy analysis provides information about the material's bonding environment and molecular structure. The surface and textural properties of the materials were verified using Brunauer–Emmett–Teller (BET) and contact angle measurements. The fabricated sensor exhibits excellent linearity in a wide detection range from 0.1 fM to 0.5 mM with a sensitivity of 0.1202 mA (fM)⁻¹ (cm)⁻². This LDO/NF sensor displays a limit of detection (LOD) of 0.0876 fM and a limit of quantification (LOQ) of 0.265 fM (S/N = 3.3). The outstanding performance of the sensor towards atrazine detection can be attributed to the availability of numerous catalytic active sites acquired by combining porous nickel foam and layered Ni–Fe LDO. Selectivity studies authenticated the excellent specificity of the sensor towards atrazine in the presence of various interfering analytes such as urea, uric acid, ibuprofen, human serum albumin, bovine serum albumin, glucose, sodium, and potassium ions with 100-fold higher concentrations. Real sample analysis was carried out in tap water and excellent recoveries of 105.4 and 97.38% were obtained, proving that the fabricated LDO based flexible sensor possesses promising potential in environmental and clinical applications.