Laser‐Induced Graphene on Gelatin‐Functionalized Cellulose Paper for Efficient Interfacial Solar Steam Generation

Interfacial solar steam generation (ISSG) offers a promising and eco-friendly approach to produce clean water efficiently. As a green and sustainable material, cellulose paper has been extensively used in ISSG. However, conventional methods for transforming cellulose paper into photothermal material are still cumbersome. In this work, a cellulose paper-based solar evaporator is fabricated by laser engraving. In detail, through a pretreatment process with a composite gelatin coating followed by laser direct writing, the study achieves one-step in-situ fabrication of cobalt-doped graphene on cellulose paper. The gelatin-based coating is formulated using cobalt nitrate and gelatin as precursor materials. The synergistic effects of cellulose paper's natural porous fibrous framework and gelatin coating enable the formation of a 3D porous graphene structure with superior capillary performance after laser engraving. Under 1 sun irradiation, the as-fabricated paper-based evaporator decorated with metallic cobalt and cobalt oxides nanoparticles achieves an evaporation rate of 1.50 kg m^-2 h^-1 with a 92.5% evaporation efficiency and excellent seawater desalination performance. The as-developed paper-based evaporator exhibits significant potential in seawater desalination and wastewater treatment, offering a practical technological pathway to produce freshwater.