Novel oil-repellent photothermal materials based on copper foam for efficient solar steam generation

Abstract Solar steam generation (SSG) has emerged as one of renewable and environmentally friendly technologies for production of fresh water. Here, we demonstrate the preparation of a novel oil-repellent photothermal materials based on copper foam (CF) for efficient SSG. Only by a simple chemical oxidation treatment on CF (named as R–CF), the smooth CF skeleton changes to be rough, leading to an enhanced light absorption of up to 90% which is far higher than that of untreated CF (10–70%). By combination of its high porosity (89.6%) and high specific surface area (230 m2 g−1), the R–CF shows superior ability on SSG as well as salt-resistance, i.e., its evaporation efficiency in water and high saline solution reaches 85.25% and 70.19% under 1 kW m−2 irradiation, respectively. In addition, R–CF was further treated by a surface chemical modification to achieve hydrophilicity while oil-repellent wettability (named as OR-R-CF), enabling it solar vaporization even in oily water, e.g., an evaporation efficiency of 77.0% was obtained in oily water, which is great advantageous to those existing photothermal materials usually suffer the drawbacks of poor oil-repellent or anti-fouling property and thus shows significant potentials for practical SSG applications in both seawater and oily water.