Carbon nanotubes@polydopamine/nickel foam with a wavy shape applied for efficient solar-driven seawater desalination

Solar-powered water evaporation has been recognized as a potential water purification regeneration technology to alleviate the issue of global water shortage. Interfacial solar steam generation (ISSG) with a high rate of evaporation and high photo-thermal conversion efficiency is very desirable. Herein, a scalable, high-efficiency and surface tunable ISSG was developed by carbon nanotubes (CNTs) loaded on polydopamine (PDA) modified nickel foam (NF) with a honeycomb three-dimensional (3D) network structure. The surface of CNTs@PDA/NF (CPNF) solar evaporator was designed as the 3D wave-like for further improved water evaporation. The as-prepared solar steam generator has an evaporation rate of 1.61 kg m−2 h−1, and photo-thermal conversion efficiency of 91.0 % at 1.0 solar irradiance. Moreover, it displays efficient purification ability for heavy metal ions in seawater and lake water, and the concentration of Na+, Mg2+, K+ and Ca2+ in the desalinated condensate is in line with the World Health Organization's drinking water standards. Additionally, the dye-contaminated wastewater can also be purified and treated to be drinking water. Furthermore, it has a good salt self-melting function. In sum, this work provides some new insights for designing innovative solar evaporators with outstanding photothermal conversion capability.