Structural Refinement and Enhanced Interfacial Electrochemical Properties of Ultrasonic-Assisted Molasses-Derived LaFeO3 Nanoperovskites

LaFeO3 nanoperovskites were synthesized through a sugarcane-molasses-assisted combustion route using mechanically stirred (MLP) and ultrasonic-assisted (ULP) activation strategies to investigate the influence of synthesis conditions on structural and interfacial electrochemical properties. X-ray diffraction and Rietveld refinement confirmed the formation of orthorhombic LaFeO3, while ultrasonic-assisted synthesis promoted improved phase homogeneity and reduced crystallite size compared with mechanically stirred combustion. Transmission electron microscopy revealed lower agglomeration and improved particle dispersion for ULP materials, whereas thermal and vibrational analyses confirmed the formation of thermally stable LaFeO3 nanoperovskites containing residual biomass-derived species associated with the combustion process. Electrochemical characterization at screen-printed carbon electrodes demonstrated that ultrasonically synthesized LaFeO3 significantly enhanced interfacial charge-transfer behavior, yielding lower charge-transfer resistance (435 Ω), increased electroactive surface area (0.149 cm2), and improved heterogeneous electron-transfer kinetics relative to MLP and bare electrodes. The LaFeO3-modified interfaces additionally exhibited distinct electrochemical oxidation behavior toward 2-aminothiazole (2AT) and 2-aminooxazole (2AO) under acidic conditions. Scan-rate analyses revealed predominantly diffusion-controlled irreversible oxidation processes, while pH-dependent studies indicated proton-coupled electron-transfer behavior during electrooxidation. The combined structural and electrochemical results establish clear process–structure–property relationships linking ultrasonic-assisted green synthesis, nanostructural organization, and interfacial electrochemical performance in LaFeO3 nanoperovskites.