A simple, natural 3D honeycomb structure achieving high photothermal conversion and sustainable salt-resistance for efficient desalination and potential electricity generation

Excellent light absorption and suppressed salt crystallization are required for solar evaporators to operate continuously and efficiently. Herein, we report a waste biomass-derived solar evaporator (Le/CNTs-corn stalk) with natural 3D honeycomb structure and sustainable salt-resistance for efficient desalination and potential electricity generation. This simply fabricated 3D light-absorbing nanostructure greatly increases the light transmission distance, achieving significant boost in light absorption of 94.8 % and photothermal conversion efficiency of 92.5 %. Moreover, a spontaneous salt exchange capability between vascular bundles and laser engraved channels is developed according to the Hagen-Poiseuille's law. Salt concentration difference formed by the volume flowrate is alleviated to facilitate salt dissolution and prevent salt accumulation on the surface, enabling to evaporate effectively for 8 h even in 10 % salt solutions. In addition, tentatively inserted carbon nanotubes on its internal channel surface raises the total zeta potential and causes surface negative charge. A promising electricity generation potential is explored with continually generating a steady voltage of similar to 136 mV. Our work provides a sustainable and massive strategy to realize efficient water production and simultaneous electricity generation using sufficient solar energy and biomass resources.

Automated summary

In this study, a waste biomass-derived solar evaporator (Le/CNTs-corn stalk) with a natural 3D honeycomb structure and sustainable salt-resistance was developed for efficient desalination and potential electricity generation. The 3D light-absorbing nanostructure greatly increased the light transmission distance, resulting in significant improvements in light absorption and photothermal conversion efficiency. The evaporator also exhibited spontaneous salt exchange capability and prevention of salt accumulation, allowing for effective evaporation even in high salt solutions. Additionally, the inserted carbon nanotubes enabled promising electricity generation potential. This work provides a sustainable strategy for efficient water production and simultaneous electricity generation using solar energy and biomass resources.