A Shape-Recoverable Aerogel With Lowered Surface Energy for Highly Efficient Solar Steam Generation

A porous-architected matrix is advantageous for solar steam generation because of its large evaporative surface available for vapor production. However, most of the solar evaporators have been constructed based on hydrophilic building blocks, which carry a high-energy surface for hindering water molecule departure. To overcome this issue, incorporating hydrophobic moieties with a low-energy surface in the evaporator skeleton opens an opportunity for boosting water vaporization. Herein, an interconnected porous aerogel has been fabricated by introducing hydrophobic carbon nanofibers (CANF) in the aerogel framework via a Pickering emulsion-mediated synthesis strategy. The plentiful pores in the resultant aerogel facilitated the vapor formation and diffusion process, while its lowered surface energy eased the vapor detachment from the evaporative surface. An ultrahigh evaporation rate of 7.573 kg m^-2 h^-1 is attained over the obtained aerogel under 1.0 sun. By applying an external convective flow (2 m s^-1), its internal pores could be maximally utilized to deliver a remarkably increased evaporation rate of 18.079 kg m^-2 h^-1. This study offers an inspiration for surface wettability adjustment and structure tailoring toward the real-world applications of solar vapor generation.