Three-dimensionally interconnected porous PDMS decorated with poly(dopamine) and Prussian blue for floatable, flexible, and recyclable photo-Fenton catalyst activated by solar light

Abstract Floating photocatalysts (FPCs) have recently attracted considerable interest for water treatment owing to their uniform light utilization regardless of their location in water and facile recycling. Various materials (e.g., polystyrene, silica gel, and glass) have been explored as self-floating substrates; however, these materials have certain limitations such as a low light transmittance, mechanical instability during floating, and insufficient adhesion with the active photocatalyst nanoparticles (NPs). Herein, we propose three-dimensionally interconnected porous poly(dimethylsiloxane) (3D-p-PDMS) as a new potential self-floating substrate with high transparency, elasticity, and chemical stability for FPCs. 3D-p-PDMS was fabricated using sacrificial alginate hydrogel beads, which could be easily removed by heat treatment. On the internal surface of 3D-p-PDMS, Prussian blue (PB) NPs were conformally deposited using polydopamine (PDA) as an adhesion-promoting layer (3D-p-PDMS@PDA@PB). The 3D-p-PDMS@PDA@PB photocatalyst can be a promising solar-active photo-Fenton catalyst because of its broadband absorbance and the presence of iron (in PB), along with its excellent mechanical and optical properties. With optimized conditions (pore size and density), 3D-p-PDMS@PDA@PB showed a high photo-Fenton performance for degrading model dye contaminants (methylene blue, methyl orange, and Congo red). Furthermore, 3D-p-PDMS@PDA@PB exhibited excellent recyclability and an insignificant decrease in photo-Fenton activity over five cycles of reuse.