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 (similar to 3.6 A & ring;), while rGO showed efficient reduction with the removal of oxygenated functional groups. The hybrids exhibited similar band gap energies (similar to 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 similar to 3350 G (g approximate to 2.08) and the appearance of a stronger carbon-related peak near 3550 G (g approximate to 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.