Enhanced solar-driven interfacial evaporation through a reduced graphene oxide–coated perforated wood structure

• A passive rGO-coated perforated wood structure for solar desalination was developed. • The rGO coating achieved 97% solar absorption across 250–2500 nm. • Evaporation reached 1.41 kg/m²-h with 95% efficiency under 1 sun, 3.5 wt% NaCl. • The evaporation rate was 236% higher than uncoated wood without perforation. • Stable evaporation was maintained during a 15-hour test without salt fouling. Solar-driven interfacial evaporation offers a promising and energy-efficient approach for seawater desalination. However, challenges such as limited solar absorption, salt accumulation, and inefficient water transport constrain performance. In this study, a reduced graphene oxide (rGO)-coated pine wood evaporator with perforated holes was developed to enhance solar absorption and salt rejection. The rGO coating provided strong broadband absorption of 97% across the 250–2500 nm spectrum, while the drilled holes facilitated salt transport and continuous water replenishment. Under 1-sun irradiation with a 3.5 wt% NaCl solution, the rGO-coated perforated wood achieved an evaporation rate of 1.41 ± 0.08 kg/m²-h and a solar-to-vapor conversion efficiency of 95%, representing a 236% improvement over uncoated wood without perforation. Moreover, stable evaporation was maintained during 15-hour continuous operation and a 3-hour outdoor test without major salt fouling. The evaporation phenomena were further explained using thermal analysis. Integrating perforated wood structures with rGO photothermal coatings offers a cost-effective and scalable route toward high-performance solar desalination for sustainable freshwater generation.