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To remedy the drawbacks of weak solar‐thermal conversion capability, low thermal conductivity, and poor structural stability of phase change materials, pyramidal graphitized chitosan/graphene aerogels (G‐CGAs) with numerous radially oriented layers are constructed, in which the long‐range radial alignment of graphene sheets is achieved by a novel directional‐freezing strategy. A G‐CGA/polyethylene glycol phase change composite exhibits a thermal conductivity of 2.90 W m−1 K−1 with a latent heat of 178.8 J g−1, and achieves a superior solar‐thermal energy conversion and storage efficiency of 90.4% and an attractive maximum temperature of 99.7 °C under a light intensity of 200 mW cm−2. Inspired by waterlilies, solar‐responsive phase change composites (SPCCs) are designed for the first time by assembling the G‐CGA/polyethylene glycol phase change composites with solar‐driven bilayer films, which bloom by day and close by night. The heat preservation effect of the solar‐driven films leads to a higher temperature of SPCC for a longer period at night. The SPCC‐based solar–thermal–electric generator achieves output voltages of 499.2 and 1034.9 mV under light intensities of 200 and 500 mW cm−2, respectively. Even after stopping the solar irradiation, the voltage output still occurs because of the latent heat release and the heat preservation of the films. [ABSTRACT FROM AUTHOR]

Solar‐driven steam generation has emerged as a sustainable technology for addressing freshwater scarcity. However, significant challenges still exist in developing high‐performance, multifunctional evaporators that are adept at both efficiently evaporating water and degrading pollutants, primarily because of the trade‐offs among functional designs. Here, a self‐floating solar evaporator is reported by functionalizing balsa wood with solar‐thermal conversion material carbon nanotubes and catalytic manganese dioxide (MnO2) nanoflowers for simultaneous solar evaporation and pollutant degradation. MnO2 nanoflowers are rich in oxygen vacancies that can effectively activate peroxymonosulfate to generate reactive oxygen species for efficient organic pollutant degradation. A distinctive non‐wetted porous interior structure and a precisely targeted water pathway are spontaneously established in the multifunctional evaporator, ensuring fast water supply, thermal insulation, efficient mass transfer, and high buoyancy. The resulting evaporators successfully combine an impressive evaporation rate of 2.74 kg m−2 h−1, a high pollutant degradation efficiency (98.3% for 100 mg L−1 tetracycline and 97.4% for 200 mg L−1 Methyl orange), and stable self‐floating and self‐standing capabilities that ensure long‐term operation stability even in complex real‐world environments. This work provides an approach to design multifunctional solar evaporators, ensuring strong alignment with practical requirements while expanding their potential application scenarios. [ABSTRACT FROM AUTHOR]