Ag/Ag3PO4 Nanocomposite forSimultaneous Interfacial Evaporation, Thermoelectric Generation, PhotocatalyticDegradation and Sterilization

Abstract To enhance solar energy utilization efficiency and reduce device cost, a multifunctional solar-driven photothermal conversion device with tunable thickness was constructed by loading Ag/Ag3PO4 composites with varying Ag/Ag3PO4 ratios onto flexible melamine foam (MF) using poly(vinyl alcohol) (PVA) as a binder. The synergistic interaction between Ag and Ag3PO4, combined with the porous architecture of MF, endows the device with integrated capabilities for interfacial evaporation, thermoelectric power generation, photocatalytic degradation, and sterilization. The optimal device achieves a water evaporation rate of 5.13 kg m–2 h–1 and a thermoelectric power density of 1.73 W m–2 under 1.0 kW m–2 solar irradiation. It also completely degrades Rhodamine B within 30 min and inactivates Escherichia coli within 40 min. The Ag/Ag3PO4 ratio critically governs the multifunctional performance, with Ag-rich composites favoring interfacial evaporation, thermoelectric conversion, and sterilization, whereas Ag3PO4-rich composites exhibit superior photocatalytic activity. Device thickness exerts a minor influence on evaporation but significantly affects thermoelectric output. Low-field nuclear magnetic resonance and differential scanning calorimetry analyses reveal that the hydrophilic porous framework reduces the water evaporation enthalpy by promoting the formation of weakly hydrogen-bonded intermediate water. Outdoor experiments conducted under different environmental conditions further demonstrate that ambient humidity has a noticeable impact on interfacial evaporation. This work provides a versatile strategy for developing high-performance photothermal materials to address freshwater scarcity, energy shortage, and environmental pollution.