Advanced Sonochemical Engineering of PANI/TiO₂ and Ag/PANI/TiO₂ Nanocomposites for High-Performance Photocatalysis

Polyaniline/titanium dioxide (PANI/TiO₂) is a multifunctional nanocomposite composed of conductive polyaniline (PANI) and titanium dioxide (TiO₂) nanoparticles. It has attracted considerable interest for environmental remediation, particularly in the photocatalytic degradation of organic dyes and water pollutants. Incorporating PANI into TiO₂ improves charge transport and extends light absorption into the visible region, addressing limitations of pure TiO₂ photocatalysts. The addition of silver nanoparticles (Ag) can further enhance photocatalytic efficiency by promoting charge separation and increasing visible-light activity.

At the PANI/TiO₂ interface, efficient charge transfer suppresses the recombination of photogenerated electron–hole pairs, leading to improved photocatalytic performance under both UV and visible light. Upon UV irradiation, TiO₂ generates electron–hole pairs. Electrons migrate to the PANI matrix while holes remain in TiO₂, enabling effective charge separation and extending carrier lifetimes.

In this study, crystalline PANI/TiO₂ and Ag/PANI/TiO₂ nanocomposites were synthesized using a sonochemical method. Both composite photocatalytic materials were synthesized using commercial titania(Kronos). For the PANI/TiO₂ the amino group loading on TiO₂ is 30% w/w. For the Ag/PANI/TiO₂ the amino group loading is 47% w/w and the Ag loading is 3%w/w on TiO₂. The band gap of the new semiconductors is improved. (TiO₂ 3.1, Ag/PANI/TiO₂ 3.05, PANI/TiO₂ 2.9).
The synthesized materials were characterized using X-ray diffraction (XRD) for identifying their crystal structure, scanning electron microscopy (SEM) for studying their morphology and size distribution, and UV-Vis spectroscopy for studying the energy gap of the photocatalysts.
All catalysts were tested for the photocatalytic degradation of organic pollutants using UV radiation. Methylene blue (MB) has been used as model pollutant for the application of photocatalysis.
The composite of Ag/Kronos/PANI gives results of almost 100% degradation of ΜΒ namely 98.7% under solar irradiation
The TiO2 semiconductor have been improved and enhanced through the preparation of the composites.