Rapid photothermal wrinkled MXene/hollow CuCo-MOF@PDMS sponge for fast viscous oils separation

Viscous oil spills (e.g., petroleum and diesel) in marine environments and domestic oily wastewater pose seriously ecological and public health risks owing to their high viscosity and poor fluidity, making the remediation a very urgent challenge. To address these issues, we designed an inherently hydrophobic MXene/hollow CuCo-MOF (H-CuCo-MOF)@PDMS sponge featuring an instantly photothermal response and a multiscale wrinkled structure. The confined effects of H-CuCo-MOF and MXene synergistically generate an efficient electron transport network, where interfacial charge transfer enhances carrier lifetime, thereby prolonging photothermal conversion efficiency. In Addition, the high specific surface area of H-CuCo-MOF and the layered structure of MXene increase confined adsorption sites while preventing MOF aggregation. Stress mismatch between flexible PDMS and rigid MXene form a highly wrinkled architecture, effectively mitigating MXene stacking. Under 1-sun irradiation, the sponge’s surface temperature quickly reaches ∼80 °C within 20 s, altering surface tension and inducing the Marangoni effect to accelerate oil absorption. Moreover, taking advantages of high match between the coated sponge and the viscous oil, the separation efficiencies are exceeding 95 % for diesel oil and rapeseed oil, and 82.7 % for crude oil. The material also proves superior durability, maintaining stable hydrophobicity after 150 friction cycles, exceptional mechanical recovery (99.2 % after 10 compressions), and notable salt resistance and antibacterial properties.