Bi-doped VO₂ coated onto wood as a highly efficient photoabsorber in interfacial solar steam generation

Addressing the challenge of water scarcity effectively involves employing a scalable, affordable, maintainable, porous, and efficient interfacial surface solar steam generator (ISSG). Herein, we explore that the efficacy of Bi-doped VO₂ (Bi:VO₂) as an efficient photothermal material coated on poplar wood is investigated within the ISSG of seawater. The integration enhances the photothermal conversion efficiency of VO₂, primarily via the surface plasmon resonance (SPR) effect. The optimal performance was achieved for Bi:VO₂ with the concentration of 2 g L⁻¹. This configuration achieved a remarkably high evaporation flux of 3.4 kg m⁻² h⁻¹ and was achieved under the power density of 3 sun (1 sun = 1 kW m⁻²), surpassing the evaporation rate of seawater alone by sixfold. Significantly, this photoabsorber reduced Na⁺ concentration in seawater from 1200 to 100 mg L⁻¹. The high ISSG performance of the Bi:VO₂ photoabsorber in the ISSG can be attributed to several factors, notably the absorption of visible and near-infrared light, the SPR effect induced by Bi, and the low thermal conductivity and porous structure of wood as a substrate. Furthermore, the Bi:VO₂ photoabsorber demonstrates remarkable stability, maintaining consistent efficiency even after 10 cycles.