Sustainable desalination device capable of producing freshwater and electricity

Freshwater shortage and the growing demand for electricity are the most common issues on the path toward achieving global sustainability. Therefore, finding creative solutions involving the use of renewable energy sources presents the main challenge. Herein, we developed a cost-effective and highly efficient 2-in-1 integrated conical device consisting of multi-walled carbon nanotubes deposited filter paper, and iron wire, capable of simultaneously generating not only freshwater but also electricity from seawater. The 3D multi-walled carbon nanotubes/paper conical structure is an interconnecting link between steam and electricity generation, providing spacious surface area for both interfacial evaporation and oxygen reduction reaction (as a cathode of metal-air battery). The use of multi-walled carbon nanotubes not only secure high broadband light absorptance (~97% in UV–Vis-NIR) but also its conductivity is vital for efficient electricity generation. The device is capable of generating a power density of 13.50 W·m−2 while maintaining an evaporation rate of 1.53 kg·m-2·h−1 under 1 kW·m−2 solar illumination. In the current implementation, the energy density and built-in characteristics of the device, along with desalination capabilities can be a modest but invaluable solution for freshwater and energy needs in off-grid areas.