Plasmon‐Driven Defect Healing in Graphene Oxide for Green Fabrication of Superhydrophobic Viscous Oil‐Absorbent With Excellent Photothermal Performance

Chemical reduction of graphene oxide (GO) often requires harsh conditions and introduces structural defects, limiting its application in photothermal‐driven oil spill remediation. Herein, we report a novel plasmon‐driven photochemical reduction strategy using silver nanoparticles (Ag NPs) to achieve defect healing and efficient reduction of GO under solar irradiation at room temperature. The localized surface plasmon resonance (LSPR) of Ag NPs not only promotes the deoxygenation of GO to form a superhydrophobic surface but also repairs the conjugated structure of GO via hot electron transfer, reducing its defect density by 21%. The resulting Ag NPs@rGO composite exhibits strong solar‐spectrum absorption (93.8%) and high photothermal conversion efficiency (89.7%). When coated on a polyurethane (PU) sponge, the material rapidly heats to 81°C within 60 s under 1 sun irradiation, significantly reducing the viscosity of crude oil and achieving an adsorption capacity of 47.2 g/g, six times higher than that of conventional carbon‐based sponges. Remarkably, the sponge maintains stable adsorption performance over 36 absorption‐desorption cycles and demonstrates exceptional chemical/mechanical durability. This study provides an eco‐friendly approach for fabricating high‐quality rGO and highlights its potential for sustainable environmental remediation material.