High-performance water purification and desalination by solar-driven interfacial evaporation and photocatalytic VOC decomposition enabled by hierarchical TiO2-CuO nanoarchitecture

Solar-driven interfacial evaporation for clean water generation has drawn significant attention as a promising and environmentally friendly avenue to tackle the global issue of water scarcity. The collected condensate can be free from most pollutants and impurities of diverse undrinkable water sources, such as heavy metals, organic dyes, minerals, and salts. However, when water is contaminated by volatile organic compounds (VOCs), this approach is ineffective because VOCs also evaporate and even can be enriched in the condensate. Here, we demonstrate TiO2-loaded CuO nanowire-covered Cu foam (TiO2-CuO-Cu-foam) for efficient solar-driven interfacial evaporation and synchronous removal of VOCs via photocatalytic degradation. The TiO2-CuO-Cu-foam nanoarchitecture possesses high solar absorption, quasi-one-dimensional water pathway, super-hydrophilicity for ultrafast water transport, long-term stability, and potential for cost-effective and scalable production for both VOC removal and desalination, meeting World Health Organization potable water standards. Our TiO2-CuO-Cu-foam evaporator simultaneously demonstrates high solar evaporation efficiency of 86.6% and efficiency of 80.0% for the removal of VOCs under one sun (i.e., 1 kW m(-2)). This result may open new opportunities for energy-efficient, clean water generation from real-world water sources using solar energy. Novelty Statement TiO2-loaded CuO nanowire-covered Cu foam (TiO2-CuO-Cu-foam) was obtained through the facile and green synthesis process. The TiO2-CuO-Cu-foam nanoarchitecture possesses high solar absorption due to surface nanostructuring, quasi-one-dimensional water pathway for localized thermal management, super-hydrophilicity for ultrafast water transport, TiO2-CuO heterojunction for enhanced photodegradation of VOCs without consumption of chemical reagents, long-term stability, and potential for cost-effective and scalable production. The nanoarchitecture is employed for clean water generation from real-world water sources.