Innovative high-energy nanocomposite absorbers for superior solar-driven water desalination through broadband solar energy harvesting

A novel solar-driven water desalination system utilizing a full-band spectrum approach with thermal fluids composed of innovative nanocomposite materials as solar absorbers is developed and evaluated. The study investigates the role of light-matter interactions, driven by nanostructure type, size, and solar radiation intensity, in enhancing photothermal conversion efficiency and maximizing solar evaporation performance. The results demonstrate that composite materials such as Fe₂O₃@Au, Graphite@Au, and ZnO@Au enhance the solar evaporation rate by 125.86, 146.43, and 229.55 %, respectively, compared to their conventional counterparts. Furthermore, advanced ZnO-based composites (ZnO@Ag, ZnO@Au, ZnO@Al, and ZnO@Cu) significantly boost evaporation rates by 317.14, 265.72, 314.29, and 331.43 %, respectively, due to enhanced light-matter interactions and optical absorption. At elevated solar irradiation densities (2500 W/m2), Fe₂O₃@Cu, Graphite@Cu, and ZnO@Cu composites show substantial increases in evaporation rates of 808.08, 787.27, and 766.63 %, along with heat gain improvements of 234.96, 222.06, and 210.15 %, respectively. Moreover, reducing the shell thickness to 4 nm of these materials further enhances energy transfer by improving nanoparticle-fluid interactions, leading to faster heating and vaporization. Graphite@Ag, Graphite@Au, Graphite@Al, and Graphite@Cu composites, thus, exhibit improved heat gain by 4.35, 8.19, 2.7, and 1.55 %, respectively, resulting in evaporation rate improvements of 8.66, 16.72, 5.1, and 3.36 %. Enhancing the core dimension from 10 to 40 nm lessens interfacial interactions, on the other hand, leading to a decrease in evaporation rates. Overall, these innovative colloidal solutions significantly enhance the solar desalination systems’ performance, offering a promising, cutting-edge solution to alleviate global water scarcity.