Flexible polyurethane foam supported ZnO nanorods-graphene hybrids for efficient broad-spectrum photodegradation of toluene

A novel flexible hybrid photocatalyst was first fabricated by immobilizing zinc oxide nanorods (ZnO NRs) with graphene oxide (GO) and reduced graphene oxide (rGO) on a three-dimensional (3D) polyurethane (PU) foam. Structural and optical analyses confirmed the formation of well-aligned ZnO NRs and successful hybridization with GO and rGO layers. GO exhibited an expanded interlayer spacing (∼3.6 Å), while rGO showed efficient reduction with the removal of oxygenated functional groups. The hybrids exhibited similar band gap energies (∼3.22 eV), however, GO and rGO modification broadened light absorption into the visible region (400–700 nm) and reduced photoluminescence (PL) intensity. Electron spin resonance (ESR) results indicated suppression of the ZnO-related signal at ∼3350 G (g ≈ 2.08) and the appearance of a stronger carbon-related peak near 3550 G (g ≈ 1.90). rGO modification improved toluene removal efficiency under UVA light, from 79 % to 96 % and increased CO₂ conversion proportionally. The flexible hybrids also maintained stable performance with less than 5 % loss of efficiency over five cycles, confirming their structural durability.