extensive attention as one of the hot topics in fast-growing disciplines. [7][8][9][10][11][12] A typical SDIE system contains solar absorber (i.e., photothermal materials), substrate, and bulk water. The absorber materials convert the incident light into heat, which will heat the water at the air/absorber interface and drive the continuous water evaporation. The substrates implement the water transport and replenishment, meanwhile work as the thermal-insulating materials. An ideal evaporator should have some required attributes, including broadband solar absorption, efficient photothermal conversion, rapid water transport, and excellent heat insulation. [13] The photothermal materials for SDIE mainly include plasmonic metals, [10,14,15] semiconductor, [16,17] and carbon materials. [18][19][20][21][22] Carbon materials, represented by graphene oxide (GO), [23][24][25] are the most competitive candidates due to their low cost, excellent photothermal property, and high processability. The photothermal conversion mechanism of carbon materials is ascribed to the lattice vibration of carbon framework, which is triggered by the excitation of photo-induced electrons from the highest occupied molecular orbital to the lowest unoccupied molecular orbital and the subsequent relaxation process. [13] When the lattice points of carbon atoms are collided with the relaxation electrons, carbon atoms will vibrate. Generally, the vibrational amplitude of the carbon lattice points can be improved by the larger lattice spacing, thus facilitating the solar-to-heat conversion. Biomass materials, in particular woods, hold advantages of structural composition, including abundant microchannels, low thermal conductivity, low density, and high hydrophilicity. [26,27] Thus, woods show great potential as thermally insulative substrates for SDIE. [22,28] However, the intrinsically low solar absorbance of natural woods impedes their further solar applications. [29,30] As such, extensive efforts have been done to improve the solar absorption capability of woods, such as surface modification. [31,32] Hu's group has proposed a "treelike design" principle to implement solar desalination by horizontally cutting the natural wood and selectively carbonizing the top surface to fabricate a two-layered solar evaporator. [33] Although the solar evaporator initially works in salted water, the salt can easily crystallize and accumulate on the evaporative surface with the continuous water evaporation, which Solar-driven water evaporation technology holds great potential for mitigating the global water scarcity due to its high energy conversion efficiency. Lowering the vaporization enthalpy of water is key to boost the performance of solar-driven desalination. Herein, a highly hydratable hydrogel (PMH) network, consisting of modified needle coke as photothermal material and polyvinyl alcohol (PVA) as hydratable matrix, is crafted via simple physical cross-linking method. When capitalizing on the PMH as evaporator for 3.5 wt% NaCl solution, a high evaporation ...

Tuning the surface topography of solar evaporators is of significance for boosting light absorption and enhancing solar‐to‐vapor efficiency. Herein, a novel strategy to manipulate the surface topography of graphene oxide (GO) via electrostatic assembly coupled with in situ polymerizations of aniline is reported. The GO surface is fully hybridized with the polyaniline (PANI) nanocone arrays, manifesting periodic structures with highly foldable configurations. Additionally, the PANI arrays tune the surface chemistry of GO and retard the redispersion of GO into water, thus enabling corresponding composite (PG) robust structural durability. Featuring these intriguing attributes, when applied as an evaporator in pure water, the PG delivers an improved evaporation performance of 1.42 kg m−2 h−1 and a high evaporation efficiency of 96.6% under one sun illumination. Further investigations reveal that the periodically conical structures of PANI over GO surface strengthen light absorption via multiple reflections and facilitate heat localization. Desalination test substantiates the reliability of PG for practical freshwater production. The numerical simulations and optical microscopy observation exhibit the surface topography‐strengthened vapor generation effect. This study sheds new light on the rational manipulation of surface topography of photothermal materials for high‐efficiency solar evaporation.

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