Interfacial solar steam generation by sawdust coated with W doped VO2.

Interfacial solar steam generation (SSG) has emerged as a promising solution to address the global challenges of water scarcity. Herein, for the first time, by pressing micro-scale sawdust into a polystyrene mold using a manual hydraulic press and enclosing it in an aluminum grid (S/Al), a substrate for SSG was made. Adjusting the porosity of the SSG device has a significant effect on the evaporation performance due to its potential in regulating the transfer of bulk water to the evaporation surface and controlling the thermal conductivity of substrate. The optimal sawdust-based photoabsorber with a 62% porosity represented 59% evaporation efficiency under 2.2 kW m−2. In addition, to improve the photothermal performance for the first time, vanadium dioxide nanoparticles doped by tungsten (W3-VO 2) as a photothermal layer on the sawdust-based substrate were used. The results were compared with those of carbonized sawdust-based substrate supported by black aluminum grid (S/C/Al–B). The excellent performance belonged to S/Al/W3-VO 2 device with 90% evaporation efficiency under 2.2 kW m−2 which was 3.3 and 1.2 times greater than pure water and S/C/Al–B, respectively. The concentration of four ions of Na+, Mg2+, K+, and Ca2+, which are responsible for the salinity of water, in the collected seawater after condensation of vapor decreased by about three orders of magnitude. Due to high performance, environmentally friendly, cost-effectiveness, and availability of the proposed device, the S/Al/W3-VO 2 photoabsorber can be used in remote areas for large-scale applications. Herein, the double-layer SSG device consisting of sawdust as a substrate and tungsten-doped vanadium dioxide NPs as photothermal material is designed. The advantages of sawdust including low cost, accessibility, ability to regulate porosity leads to control of water transfer and TC of the substrate. Although the performance of the double-layer SSG device is optimized by adjusting the permeability of substrates, heat loss, long-term stability, and cost-effectiveness of the devices are still challenging and require further research. In this work, sawdust is molded into polystyrene to minimize the manipulation of the chemical structure and then it is pressed under various pressures. Finally, it is enclosed in an aluminum grid to prevent the photoabsorber device from being damaged after the expansion due to water absorption. The aluminum grid in addition to keep sawdust in the mold, thanks to its plasmonic properties which increases the light absorption of the SSG device. To enhance the aluminum light absorption, the color was changed to black by coating W3-VO 2 NPs on the substrate. • A cost effective approach is suggested to harvesting solar energy. • A sawdust coated with W doped VO 2 is used in interfacial solar steam generation. • Performance of the carbonized sawdust with W -VO 2 was compared. • Sawdust-based photoabsorber with the porosity of 62% showed high solar absorption. • S/Al/W3-VO 2 photoabsorber can be used as low-cost for a large-scale application. [ABSTRACT FROM AUTHOR]