Enhancement of photothermal effect of Cu2S@CuS homojunction and applications of crude oil–water separation and ice removal

The recycle of crude oil with high viscosity from wastewater and anti-icing of outdoor power transmission lines are still challenges. High photothermal responses with excellent superwetting properties are critical issues for solving these problems. In the paper, the porous nanosheet arrays of Cu2S@CuS homojunction with narrow band have been prepared by anodizing Cu foam. After the surface modification of stearic acid (STA), the array surface is endowed with excellent wetting states of super-hydrophobicity and super-lipophilicity, and is suitable for the oil–water separation. The narrow band and homojunction structure induce the excellent light absorption, and further increase the photothermal conversion efficiency of the prepared Cu2S@CuS nanoarray to the value of 8.81 %. Under the irradiation of Xe lamp with 0.1 W/cm2, the surface temperature of Cu2S@CuS nanosheet array in air promptly increases to 96.5 ℃ from room temperature of 20.9 ℃ within 30 s, and increases to 69 ℃ from room temperature within 45 s in crude oil. Obviously, the prepared Cu2S@CuS nanoarrays with excellent photothermal responses are very suitable to be used as filter film for the crude oil–water separation. With the increase of light irradiation time, the local temperature of crude oil near the filter film continues to be increased to 69 ℃ within 45 s, and the gradually warmed crude oil was continuously pumped to the oil collecting beaker through rubber pipe, showing the high efficiency and excellent stability. Of course, it is also used to efficiently separate the oil with low viscosity from oil-water mixtures and emulsion.