Plasmonic interfacial evaporation system incorporating TiN nanoparticles with AAO templates

Solar-driven interfacial evaporation systems, which efficiently drives the evaporation of liquid water through photothermal conversion, hold immense promise for addressing global water scarcity and securing clean freshwater resources. Plasmonic nanomaterials, such as gold (Au) and silver (Ag), with their unique ability to excite localized surface plasmon resonances (LSPRs), have demonstrated remarkable performance in photothermal conversion. However, these noble metal-based plasmonic materials are hampered by significant limitations, including high costs and poor stability. In this study, we introduce thermally stable titanium nitride nanoparticles (TiN NPs) with strong LSPRs as a viable alternative for realizing photothermal-driven water evaporation. Through a simple vacuum filtration technique, we assemble a TiN NP layer of a few micrometers thick onto the surface of a porous anodic aluminum oxide (AAO) template. The resulting TiN/AAO layered nanostructure capitalizes on multiple synergistic mechanisms: the plasmonic resonance of TiN NPs enhances light absorption; the low thermal conductivity of the AAO template suppresses heat dissipation; and the nanochannels of the AAO enable efficient water supply via capillary action. These features collectively elevate the solar-to-thermal conversion efficiency of the system. Under 1 Sun illumination, the TiN/AAO photothermal evaporator achieves an evaporation rate of 1.26 ± 0.05 kg m^-2·h with an impressive efficiency of 87.9%. It also exhibits > 99% light absorption across the 200-1100 nm wavelength range. This plasmonic TiN/AAO absorber represents an innovative, cost-effective, portable, and scalable solution for seawater desalination, offering a significant step forward in sustainable water purification technologies.