Pyramidal array Janus hydrogel-based solar evaporator via broadband light trapping inspired by durian peel for efficient seawater desalination.

The solar-powered interfacial evaporation approach demonstrates extensive applicability prospects within seawater desalination domains. Traditional solar energy evaporators (SE) are often designed without regard to factors such as surface structure optimization and synergistic combination of heterogeneous materials. In this study, inspired by the unique structure of durian fruit peel, a Janus composite hydrogel SE (SPP@PAM) with pyramidal array features was innovatively designed. The upper stratum of the SE comprises polypyrrole-integrated superhydrophobic pyramidal foam, with the lower stratum being a polyvinyl alcohol/agar hydrogel matrix crosslinked with aminated carbon nanotubes. The Janus structure improves evaporation efficiency while reducing droplet attachment, lowering the enthalpy of evaporation, and increasing the rate of water transfer. The results showed that the evaporation rate of SPP@PAM reached 3.54 kg·m⁻²·h⁻¹ under a single solar irradiation condition. After 18 days of cycling experiments, there was almost no salt accumulation on the surface. This research provides a new strategy for industrial-scale desalination.