Synthesis of layered Co9S8-based composites for high-efficiency rotating evaporation of saturated brine

Harvesting freshwater via solar interfacial evaporation is a promising strategy with net-zero emissions. To achieve long-term stable freshwater acquisition, researchers have developed dynamic solar-driven water evaporators. However, these evaporators exhibit limited evaporation rates due to the insufficient photothermal conversion properties of the materials used. In this study, we prepared Co9S8/CoNiO2/Au composite materials through in-situ topological transformation, thereby improving the effect of the heterogeneous crystal lattice mismatch on electron transport. By embedding these materials into a spherical polyurethane sponge, we developed a new type of self-rotating evaporator with a solar full-spectrum absorbance of 95.84 %. The evaporator stably exhibited an evaporation rate of 3.10 kg m−2 h−1 within 240 h in saturated brine. The present work provides insights into the preparation of photothermal composites and the development of high-efficiency stable solar evaporators. [Display omitted] •Co9S8/CoNiO2/Au composites with layered stacking structure were prepared.•In-situ topological conversion of double metal hydroxide precursors to improve the electron transport.•Excellent light absorption capability of Co9S8/CoNiO2/Au in the full solar spectrum.•Self-rotating evaporator exhibited an evaporation rate of 3.10 kg m-2 h-1 within 240 h in saturated brine.