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

Abstract 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.