Atomic layer deposition of Pd nanoparticles on TiO2/SnO2 nanofibers for improved visible-light photocatalytic degradation of acetaminophen

Micropollutants like acetaminophen are increasingly detected in aquatic environments, raising concerns due to their persistence and potential ecological impacts. Conventional wastewater treatment processes struggle to remove these emerging contaminants effectively, leading to growing interest in alternative approaches such as photocatalysis. Semiconductors are widely used as photocatalysts, however, most of them are unable to absorb visible light efficiently. In this work, we report the development of TiO 2 /SnO 2 composites modified with palladium nanoparticles (Pd NPs) to enhance visible-light photocatalytic activity. The nanocomposites were synthesized through electrospinning and further modified using atomic layer deposition. The resulting photocatalysts were characterized and evaluated for the degradation of acetaminophen (ACT) under visible-light irradiation. TiO 2 /SnO 2 -Pd composites achieved up to 94% degradation within 270 minutes, significantly outperforming pristine TiO 2 and TiO 2 /SnO 2 nanofibers. Scavenger tests revealed that superoxide radicals played the dominant role in pollutant degradation, followed by photogenerated holes and hydroxyl radicals. The enhanced activity was attributed to the roles of SnO 2 and Pd in facilitating electron transfer and suppressing charge carrier recombination. Recyclability tests demonstrated excellent stability over multiple cycles, highlighting the potential of these nanostructured photocatalysts for sustainable water treatment applications. • TiO 2 /SnO 2 nanofibers were successfully modified with palladium nanoparticles by atomic layer deposition. • Palladium incorporation significantly enhanced visible-light photocatalytic degradation of acetaminophen. • The composites achieved ACT degradations up to 94% and exhibited excellent recyclability. • Palladium improved charge separation in the heterostructure.