Joule-heating and solar-heating sorbents for efficient cleanup of viscous oil spills have emerged as effective strategies due to their high availability and feasibility. However, effectively integrating both the approaches to maximize energy input savings remains a significant challenge. This work aimed to develop an energy-optimized Joule-/solar-heating superhydrophobic sorbent for the remediation of viscous oil spills. To achieve this, copper foam (CF) was utilized as the substrate due to its inherently high thermal and electrical conductivity, and CuS nanosheet-coated CuO nanowires (CuS/CuO NWs) with enhanced near-infrared absorption and high-efficiency photothermal conversion were used as the functional coating. The sorbent, named H–CuS/CuO/CF, was fabricated by in situ constructing grass-like arrays of CuS/CuO NWs onto the CF skeleton and subsequent hydrophobic modification. The resultant sorbent retained the high Joule-heating effect and low energy consumption characteristic of metal-based sorbents. Additionally, it exhibited an enhanced sunlight absorption and a high photothermal effect attributed to the hierarchical nanostructure arrays of the CuS/CuO coating. The equilibrium temperature of the H–CuS/CuO/CF can achieve about 130 °C within 50 s at a low voltage of 1 V and around 67 °C within 300 s at 1.0 sun irradiation (light intensity of 1 kW/m2). The high-efficiency Joule/solar-to-heat capability of the sorbent enables the effective recovery of highly viscous oils (1.6 × 105 mPa s at 12 °C) that are challenging to manage at the ambient temperature. The continuous oil capacity reached about 3.25 × 103 kg·m–3 in 270 s under the assistance of an in situ pumping device and a low voltage input. Moreover, the resulting sorbent with a high mechanical skeleton and stable wettability showed high durability. Thus, the Joule/solar-heating H–CuS/CuO/CF sorbent with an efficient thermal conversion performance and high heat transfer offers a promising and energy-efficient strategy for all-weather cleanup of highly viscous oil spills.
