Morning Glory-Inspired 3D LIG/PDA Paper Evaporators for Efficient Solar Steam Generation

Freshwater scarcity has become a critical global issue, highlighting the urgent need for low-cost and efficient technologies for seawater desalination and wastewater purification. Inspired by the hopper-shaped corolla of the Morning Glory, which efficiently concentrates sunlight and directs water along its conical surface, we developed a paper-based solar evaporator constructed from cellulose paper via laser-induced graphene (LIG) and further modified with polydopamine (PDA) to enhance hydrophilicity. The paper substrate was folded into a three-dimensional (3D) conical structure, which enlarged the evaporation area, improved light absorption, and optimized thermal management. Under 1 sun irradiation, the optimized 3D device achieved an evaporation rate of 2.02 kg m^-2 h^-1 with an efficiency of 125.1%, outperforming its two-dimensional counterpart. The conical geometry also facilitated edge crystallization of salts, ensuring long-term operational stability. Outdoor tests further verified its capability for freshwater production, demonstrating the potential of this bioinspired, low-cost, and scalable paper-based evaporator for sustainable desalination and clean water generation.