ZnO Nanorods Aligned in a Vertical Configuration for Targeted Electrochemical Detection of Aniline.

This study demonstrates the synthesis of 1D surface vertically aligned nanorods of ZnO on the fluorine-doped tin oxide-coated glass substrate (ZnO-VANRs/FTOs) synthesized via a chemical route for the targeted electrochemical sensing of aniline. The ZnO-VANRs/FTOs were 1.57 ± 0.03 μm in length with excellent crystallinity and high density (1.52 × 10 rod no./m). ZnO-VANRs formation increased surface roughness by 2.4- and 4.7-fold compared to the bare FTOs and seeded FTOs (ZnO-seed/FTOs), respectively. The ZnO-VANRs/FTOs electrodes could increase the effective surface area from 0.154 to 0.384 cm with about 86.85% reduction in charge transfer resistance compared to the bare FTOs. The peak current response (at 0.281 V vs Ag/AgCl) of aniline deposition was boosted by 81.52% with the rise in temperature from 15 to 45 °C. The reduction of aniline at ZnO-VANRs/FTOs involved a reversible two-electron diffusion control process with a heterogeneous reaction rate constant () of 1.82 s and a formal potential () of 0.289 V vs Ag/AgCl. The ZnO-VANRs/FTOs electrode showed limits of detection of 0.193 μM (sensitivity 0.198 μA·μM·cm) and 0.588 μM (sensitivity of 0.065 μA·μM·cm) between the working ranges of 0-20 and 20-160 μM, respectively. The fabricated sensor was unprecedently selective toward aniline sensing, and -nitroaniline, chlorobenzene, chlorpyrifos, Cu, Pb, Ni, Cd, albumin bovine, , and ciprofloxacin could not interfere with aniline sensing and its sensitivity. However, the peak current was marginally decayed by 2.63% up to the 6th cycle. Moreover, ZnO-VANRs/FTOs catalyzed the sensing of aniline spiked in the environmental matrices, conforming well to liquid chromatography.