Sustainable 3D‐Printed Platforms with Durable Photocatalytic Coatings for Efficient Water Treatment

Abstract This study presents a robust and sustainable 3D‐printed scaffold with engineered surface properties for durable and wear‐resistant coating of photocatalytic nanocomposites. Copper‐doped titanium dioxide/reduced graphene oxide nanocomposites are synthesized to enable visible‐light activation, achieving 89% methylene blue removal within 60 min under visible light illumination. The coating's mechanical and chemical stability is systematically evaluated under UV exposure, sonication‐induced vibration, and cyclic regeneration using chemical washing. Scaffold design parameters, including pore architecture, surface topology, and chemistry, are optimized to enhance nanocomposite loading and retention. Among the tested infill designs, the gyroid structure provides the highest surface area (3259.2 mm²) and supports the largest nanocomposite mass. Incorporation of polydopamine as a bioadhesive significantly improves coating adhesion (378% increase in nanocomposite loading) and stability (200% reduction in leaching). Surface engineering also facilitates the formation of uniform, few‐layer coatings, resulting in a removal efficiency of 93% within 120 min, which is comparable to that of colloidal nanocomposites reported in the literature. The nano‐enabled scaffold maintains excellent performance across 30 regeneration and reuse cycles, with a final‐cycle removal efficiency of 91.4%, outperforming existing systems by more than fourfold in terms of reusability.