A Multifunctional Synergistic Solar-Driven Interfacial Evaporator for Desalination and Photocatalytic Degradation

The scarcity of freshwater resources and the treatment of dye wastewater have emerged as unavoidable challenges that need to be addressed. The combination of solar-driven interfacial evaporation, photocatalytic degradation, and superhydrophobic surface provides an effective approach for seawater desalination and the treatment of organic dyes. In this study, we fabricated a multifunctional synergistic solar evaporator by depositing cupric oxide nanoparticles onto polypyrrole (PPy) coating and subsequently modified it with a hydrophobic agent successfully. The evaporator achieved an evaporation rate of 1.48 kg m^-2 h^-1 under 1 kW m^-2 irradiation. Importantly, the evaporator exhibited a degradation efficiency of 95.9% toward the organic dye methylene blue. It is important to mention that PPy promotes the separation of photogenerated electron-hole pairs, thus improving the photocatalytic performance of cupric oxide. The salt resistance of the evaporator is evidenced by the absence of significant salt deposits on its surface even after 300 min of operation due to its superhydrophobic property. The evaporator also presents excellent resistance to acidic/alkaline/high-temperature/organic solvent environments. This solar evaporator offers a sustainable solution for water purification.