Engineered 3D-printed Bi4O5I2@hematite scaffolds for visible light photocatalytic degradation of cresols

Abstract

Catalyst leaching hampers reusability in photocatalysis, posing secondary pollution risks. In the present study, Bi₄O₅I₂ is decorated onto an engineered 3D-printed hematite scaffold (Bi₄O₅I₂@3DH), integrating additive manufacturing with photocatalysis for efficient cresol degradation in diverse water matrices. The hematite grid, fabricated via direct ink writing, exhibited excellent rheological behavior (τ_y = 24 Pa), allowing precise shape retention, while Bi₄O₅I₂ was immobilized via a simple dip-coating method. The Bi₄O₅I₂@3DH composite achieved 99.78% degradation of 20 mg L⁻¹ p-cresol within 240 min and retained 84.28% efficiency after 10 reuse cycles with negligible leaching. Density functional theory (DFT+U) simulations confirmed S-scheme heterojunction formation, facilitating interfacial charge transfer (≈−0.9 e⁻) and enhanced photocatalytic activity. The engineered scaffold performed consistently across varied water matrices, with in vitro and in silico analyses revealing reduced toxicity of degradation products. The current work demonstrates a scalable strategy for coupling additive manufacturing with advanced photocatalysis using earth-abundant minerals for sustainable water treatment.