Eco-friendly synthesis of ferric ion-polyphenol-graphene aerogel for solar steam generation

Graphene based photothermal materials show great promise in solar steam generation for seawater desalination and wastewater purification. However, the facile and green fabrication of efficient graphene aerogel light absorber remains a challenge. Here we demonstrate the eco-friendly preparation of tannic acid modified graphene as solar-to-thermal material through electrochemical exfoliation and subsequent sonication procedure. The as-prepared aerogel exhibits good photothermal effect and high solar-to-evaporation efficiency. By crosslinking with ferric ion, a more efficient ferric ion-polyphenol-graphene complex aerogel was developed to construct the high-performance solar vapor generation device. The defect-free structure of exfoliated graphene and ferric ion-polyphenol complex contributed to the high evaporation rate of 1.3 kg m −2  h −1 and energy efficiency of 86.3% under one sun illumination.