Tailoring the Morphology and Electrochemical Behavior of TiO2 Powders via Surfactant-Assisted Synthesis by a Modified Pechini Route

Abstract

Searching for sustainable alternatives to environmental challenges has driven significant interest in metal oxides, particularly TiO2, due to its versatility in energy conversion, pollutant adsorption, and electrochemical applications. TiO2 powders were synthesized via a modified Pechini method, comparing the conventional route with the use of the Tween-80 surfactant as a structure-directing agent. Structural, morphological, and electrochemical characterizations were performed to assess the impact of the synthesis on material performance. Thermogravimetric analysis (TG) revealed distinct decomposition profiles, with the Tween-based precursor exhibiting enhanced thermal stability. X-ray diffraction confirmed the formation of anatase–rutile structures, with Tween-80 favoring a higher anatase content (74.3% anatase phase). Scanning electron microscopy (SEM) and specific surface area (SBET) measurements demonstrated that Tween-80 promoted a more porous and fragmented morphology, leading to a 21-fold increase in specific surface area. ζ potential and XRD–Rietveld analysis further elucidated the influence of the organic precursor on the surface charge and crystallite size. Electrochemical impedance spectroscopy (EIS) showed a significant reduction in charge transfer resistance (65.8 kΩ), compared to that of ethylene glycol-based films (943 kΩ), while cyclic voltammetry (CV) in the presence of methylene blue indicated improved redox activity, enhancing the applicability of this TiO2 powder in several areas.