Ti2O3-based phase-change aerogels with synergetic photothermal-latent heat storage for all-day desalination

Energy time decoupling aerogel for 24 h solar desalination by photothermal PCM storage. • 91% solar absorption, 55.3 °C surface temp, 71.05 J·g −1 latent heat and excellent stability. • It has a high evaporation rate of 1.88 kg m −2  h −1 with stable cycling and salt rejection. • This work presents a viable strategy for all-day solar desalination. Interfacial solar vapor generation holds great promise for sustainable freshwater production but is fundamentally limited by the intermittent nature of sunlight. To overcome this challenge, we developed a novel composite aerogel integrating photothermal conversion and latent heat storage for continuous desalination. The aerogel was fabricated by incorporating Ti 2 O 3 nanoparticles as the photothermal medium and polyethylene glycol (PEG) as the phase-change material into a PVA/CNF scaffold via freeze-drying. Excess heat is stored during peak irradiation and released during low or no-light periods, thereby decoupling evaporation performance from direct sunlight availability. The composite aerogel achieves a broadband solar absorption of 91% and attains a surface temperature of 55.3 °C under 1 sun. It delivers a high evaporation rate of 1.88 kg m −2  h −1 and demonstrates excellent cyclic stability and salt/bacteria resistance. Outdoor experiments demonstrated its practical viability, yielding a freshwater production of 3.661 L m −2 over ten hours. This work provides a feasible material strategy for all-day solar desalination and opens avenues for efficient solar-thermal energy utilization in water purification applications.