Ternary PANI/SnO2-TiO2 heterostructure interfaces for the rapid and selective electrochemical detection of 8-hydroxyquinoline.

A ternary PANI/SnO2-TiO2 heterostructure nanocomposite was fabricated for the electrochemical detection of 8-hydroxyquinoline (8-HQ) through a combined sol-gel and in situ polymerization approach. Initially, SnO2-TiO2 hybrid nanocomposites were synthesized via the sol-gel method, followed by the in situ polymerization of aniline monomers on the hybrid surface to construct a ternary heterostructure for characterization. For electrochemical sensing applications, PANI/SnO2-TiO2 heterostructured films were fabricated on glassy carbon electrodes (GCE) through the electrochemical polymerization of aniline on pre-modified SnO2-TiO2/GCE. The structural, morphological, compositional, and electrochemical properties of the fabricated nanocomposites were systematically characterized using PXRD, UV-Vis DRS, VB-XPS, FESEM-EDS, HRTEM, BET, FTIR spectroscopy, CV, EIS, and chronoamperometry. BET analysis revealed that PANI/SnO2-TiO2 exhibited a significantly higher specific surface area (101.70 m2 g-1) than PANI/TiO2 (35.30 m2 g-1) and pristine PANI (18.70 m2 g-1), indicating enhanced electroactive surface area and abundant active sites. The developed PANI/SnO2-TiO2/GCE sensor exhibited excellent sensing performance toward 8-HQ, with a high sensitivity (224.44 μA × 10-7 M-1 cm-2), low detection limit (0.58 × 10-8 M), and wide linear range (0.1-0.8 × 10-7 M), as determined using LSV. Furthermore, remarkable selectivity, durability, reproducibility, and successful applicability for wastewater sample analysis were observed, demonstrating potential for environmental monitoring applications.