Biomimetic vertically aligned aerogel with synergistic photothermal effect enables efficient solar-driven desalination

Abstract

Taking sustainable solar energy for efficient rapid clean water production is eagerly desired to overcome the water shortage issue. However, great challenges remain in constructing short water transport channels and enhancing sunlight utilization efficiency. Herein, a biomimetic solar-driven interfacial evaporator with rapid water transport and high photothermal conversion efficiency inspired by natural-trees was successfully developed, via engineer vertically aligned hydrophilic sodium alginate (SA) aerogels while hierarchically assembled MXene interwoven carbon nanotube (CNT) networks as micro/nano light absorb layer. Due to the synergistic photothermal effect between 2D MXene nanosheets and 1D CNT with multiple reflective nanostructure and strong light-absorption over a broad spectrum, and super-hydrophilic SA with highly oriented water transport channels, which enables fast water/vapor transport while utilizing solar energy efficiently. Vertically aligned aerogel exhibits an excellent water evaporation performance which as high as 2.416 kg m−2 h−1 (deducting dark conditions) and remarkable solar energy utilizing efficiency of 90.56 %, which are extremely higher than that of most reported desalination devices. Furthermore, the solar-driven evaporator also exhibits strong antibacterial properties and long-term operation stability. The biomimetic vertically aligned aerogel with excellent water evaporation and light utilization efficiency holds great promise for high-performance water purification and desalination applications. Synopsis statementResearch on the rapid clean water production from wastewater/seawater with high solar energy utilization efficiency has become a hot topic, and solar-driven desalination offers a sustainable solution to meet water demands. This study reports a biomimetic solar-driven interfacial evaporator with oriented water transport nanochannel and multi-reflective solar absorber for efficient clean water production.