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

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.