Synthesis of mesoporous Fe3Si aerogel as a photo-thermal material for highly efficient and stable corrosive-water evaporation

Abstract

Synthesis of photothermal materials with high efficiency and anti-corrosion stability is key for photothermal corrosive-water evaporation, but remains a great challenge. Herein, for the first time, we developed mesoporous Fe₃Si aerogel as a new photothermal material for remarkably efficient and stable corrosive-water evaporation. The as-prepared Fe₃Si aerogel presented narrow mesopores with a size of 2–3 nm that could greatly reduce the thermal conductivity to 0.04 W m⁻¹ K⁻¹, which is the lowest reported value so far, and depressed the latent heat of water evaporation. The obtained Fe₃Si aerogel supported on melamine foam demonstrated outstanding seawater evaporation rate of 2.08 kg m⁻² h⁻¹ and high solar-thermal utilization efficiency of 91.8% under one solar level irradiation, exceeding those of most of the photothermal materials. Notably, owing to the strong corrosion resistance, the support-free hydrophobic Fe₃Si aerogel displayed utrastable solar-thermal water evaporation performance, with more than 1 kg m⁻² h⁻¹ of water evaporation and outstanding cycling stability in two highly corrosive solutions, namely, 0.5 M H₂SO₄ and 1 M NaOH. Therefore, we believe that the Fe₃Si aerogels have great potential for wide industrial applications such as seawater desalination, salt production, brine management and water purification.