Simply realizing durable PVDF/candle soot foam with excellent solar absorption for solar-assisted recovery of heavy oil spill

• A photothermal PVDF/candle soot sponge was prepared by sugar-templating route. • The encapsulated-candle soot endows the sponge with high sunlight absorption. • The sponge exhibits excellent mechanical properties and durability. • The sponge reduces the viscosity of crude oil via photothermal under a sunlight. • The sponge shows high sorption capacity for viscous crude oil up to 82.5 g/g. The introduction of a photothermal layer on absorbent surface is a potential solution to produce heat for promoting the absorbent performance against viscous heavy oil, but the developed photothermal absorbent is still highly desirable but challenging, considering their complicated, tedious synthesis processes and susceptible surface to mechanical damage. A simple sugar-templating strategy was promoted to fabricate a porous PVDF/candle soot sponge using sugar as a sacrificial template. The encapsulated-candle soot can not only roughen the PVDF struts for superhydrophobicity but also endows the sponge with nearly full sunlight absorption (96.5%). Under sunlight exposure, the generated heat in situ reduced the viscosity of the surrounding heavy oil. Consequently, the sponge attains a remarkable oil absorbent rate of 82.5 g/g, reaching up to the state-of-the-art levels. Benefitting from high elasticity and mechanical robustness, the sponge maintains more than 96% of its sorption capacity after 10 cycles. Moreover, the UV resistance and chemical durability in a highly salty environment enable it to respond efficiently to heavy oil spills under complex marine conditions. Owing to its simple fabrication method and outstanding integrated properties, this composite sponge is of great potential for remediating heavy oil spill. Graphical Abstract .