1O2-generating CdS quantum dots for water purification: innovative immobilization routes based on cold plasma discharge

Cold plasma discharge, surface synthesis and 3D printing were used to fabricate supported photocatalysts. • Three different approaches were employed to immobilize QDs on a fractal polymer substrate. • One of the fabrication routes allowed obtaining a 1 O 2 -generating catalyst. • This hybrid catalyst was more efficient for the purification of water than the free QDs and easy to reuse. Owing to their quantum confinement, quantum dots (QDs) can efficiently generate singlet oxygen, a highly reactive oxygen species (ROS). Although promising for photocatalytic water remediation, their practical application remains limited. Their nanoscale dimensions render them more challenging to deploy than bulk heterogeneous photocatalysts; specifically, their separation and recycling are complex, and catalyst leaching poses a significant issue. In this study, we evaluated several chemical immobilization methods initiated by cold plasma discharge (CPD) to fabricate supported QD-based catalysts for the photodegradation of organic pollutants. Using CdS QDs as a model system, we probed their capacity to generate singlet oxygen. The resin substrates were fabricated by LCD 3D printing and microtextured with fractal architectures. Among the different immobilization strategies, the most successful employed a secondary nanostructured ZnO support to enforce a monolayer dispersion of the QDs. Subsequent in situ encapsulation by a metal–organic framework (MOF) further improved the photostability of the catalyst. This study provides valuable insights and new directions for the facile surface immobilization of functional QDs within controlled architectures for the efficient remediation of organic-contaminated water. Download: Download high-res image (89KB) Download: Download full-size image