Efficient plasmonic enhanced solar evaporation achieved by laser-assisted Cu /Graphene nanocomposite

The solar-driven steam generation emerges as an appealing approach to address the pressing freshwater and energy crisis, due to the high utilization of abundant solar energy and undrinkable water resources, and its low environmental impact. Meanwhile, efficient solar absorbers featuring broadband spectra response, high solar-heat conversion, low-cost and good stability are significant to practical solar evaporation. Moreover, avoiding salt crystal accumulation on the evaporation surface thus minimizing blockage of the pathways for light absorption and vapor escape, is vital to maintain the long-term evaporation efficiency. Therefore, a portable interfacial evaporator was facilely made with a 3D-structured plasmonic enhanced photothermal nanocomposite of Cu Nanoparticles/laser-induced graphene (Cu NPs/LIG) as the efficient solar absorber via a one-step deposition method. This novel evaporator exhibits a large solar absorption (98%) over broadband spectrum (250–2500nm) that also rapidly achieves a high surface temperature (>80 °C) under 1 sun irradiation. Meanwhile, this fabricated solar-driven evaporator can realize a high evaporation rate of 2.29 kg/m².h on pure water. Moreover, due to the spontaneous salt diffusion along the vertical concentration gradients driven by the unobstructed and continuous pathways, outstanding anti-salt performance was obtained, and a high evaporation efficiency of 1.82 kg/m².h upon brine with a high salinity (20 wt%) for a long-term application was observed.