Insight into the role of polydopamine nanostructures on nickel foam-based photothermal materials for solar water evaporation

This study developed a solar evaporator by uniformly growing polydopamine nanowires (PDA NWs) on porous nickel foam (NF) substrate using a straightforward in situ approach. The synthesized material exhibited unique nanostructures, substantial hydrophilicity, and high porosity resulting in excellent light harvesting covering much of the solar spectrum. In addition, the utilized polystyrene foam support and cotton cloth resulted in a fast water supply to the evaporator along with heat localization. Good solar water evaporation rate of 1.39 kg m(-2)h(-1), with a photothermal conversion efficiency of 87.8 % was achieved at one sun (1 kW m(-2)) illumination. The PDA NWs-NF evaporator displayed high-efficiency toward salt ions rejection and met the standard required for potable water. The synthesized material displayed good reusability and stability performance in real seawater and brine (75 g/L NaCl). The self-desalting capability of the prepared evaporator is driven via chemical advection and diffusion, resulting to fast salt dissolution. Our approach in fabricating cost-effective, scalable and environmentally friendly solar-thermal converter could meet the practical needs for solar-driven seawater desalination especially for remote communities.

Automated summary

This study developed a solar evaporator with polydopamine nanowires uniformly grown on a porous nickel foam substrate. The synthesized material has unique nanostructures, high hydrophilicity, and high porosity, allowing for excellent light harvesting and efficient solar water evaporation. It also shows high-efficiency salt ions rejection and meets the standard for potable water. The evaporator demonstrates good reusability and stability in real seawater and brine. This cost-effective and scalable solar-thermal converter can meet the practical needs for solar-driven seawater desalination, especially in remote communities.