A Hydrogel‐Based Seawater Evaporator for a High Rate of Clean Water Production via Photothermal and Electrothermal Joule Heating‐Assisted Evaporation

Interfacial steam generation (ISG) at the water–air interface is one of the feasible solutions to deal with the global freshwater scarcity driven by pollution, population growth, and climate change. However, salt accumulation on light‐absorbing materials, variable weather conditions, and no sunlight at night reduce the efficacy of ISG technology. To mitigate these challenges, an innovative and simple ISG approach using starch, chitosan, and carbon black‐based hydrogel and a PDMS‐coated carbon cloth is proposed in this study. It combines the synergistic effects of photothermal and electrothermal Joule heating‐assisted evaporation for highly efficient seawater desalination that works in all weather, all day, without salt fouling on the evaporation surface. During desalination experiments, the surface temperature of the evaporator reaches ~40 °C within 10 min, achieving an impressive evaporation rate of 6.619 kg m ⁻²  h ⁻¹ under 3 V applied voltage and 1 sun illumination. These advancements pave the way for highly efficient electrothermal heating‐assisted photothermal seawater desalination systems, offering a reliable solution for all‐weather, all‐day desalination to produce freshwater while preventing salt fouling.