Topographic Manipulation of Graphene Oxide by Polyaniline Nanocone Arrays Enables High‐Performance Solar‐Driven Water Evaporation

Abstract 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.