Solar vapor generation (SVG) has emerged as a promising technique of harvesting solar energy for producing fresh water from seawater. However, two main problems of insufficient energy utilization and salt accumulation on evaporation surfaces are still challenging issues for the broad application of this technique. In this work, we demonstrate a hierarchically structured bilayer aerogel by in situ deposition of polypyrrole (PPy) inside the top layer of cellulose. The light-absorbing PPy/cellulose composite with three-dimensional (3D) hierarchical structures served to convert solar energy into thermal energy and localize the heat to power the vaporization of water contained in the cellulose network. While the porous and hydrophilic cellulose matrix enabled continuous water transport and replenishment to the upper evaporative layer. Moreover, several microcracks were formed at the PPy/cellulose surface, which assisted vapor escape and salt re-dissolution. As a result, the prepared PPy/cellulose aerogel enabled a high seawater evaporation rate of 1.42 kg m⁻² h⁻¹ at energy efficiency of 97.8% under one sun illumination. The SVG system also exhibited highly efficient and stable evaporation performance in seawater without surface salt accumulation over one week.

太阳能蒸汽发电 (SVG) 已成为一种很有前景的太阳能收集技术，用于从海水中生产淡水。然而，能量利用不足和蒸发表面盐分积累两个主要问题仍然是该技术广泛应用的挑战问题。在这项工作中，我们通过原位展示了分层结构的双层气凝胶聚吡咯（PPy）沉积在纤维素的顶层内。具有三维 (3D) 分层结构的吸光 PPy/纤维素复合材料用于将太阳能转化为热能并将热量局部化，从而为纤维素网络中所含的水的蒸发提供动力。而多孔和亲水性纤维素基质使水能够持续输送和补充到上部蒸发层。此外，PPy/纤维素表面形成了几个微裂纹，这有助于蒸汽逸出和盐的重新溶解。结果，制备的 PPy/纤维素气凝胶实现了 1.42 kg m ^-2  h ^{-1的高海水蒸发率}在一次阳光照射下，能源效率为 97.8%。SVG系统在海水中也表现出高效和稳定的蒸发性能，一周内没有表面盐分积累。