Solar vapour generation is an efficient way of harvesting solar energy for the purification of polluted or saline water. However, water evaporation suffers from either inefficient utilization of solar energy or relies on complex and expensive light-concentration accessories. Here, we demonstrate a hierarchically nanostructured gel (HNG) based on polyvinyl alcohol (PVA) and polypyrrole (PPy) that serves as an independent solar vapour generator. The converted energy can be utilized in situ to power the vaporization of water contained in the molecular meshes of the PVA network, where water evaporation is facilitated by the skeleton of the hydrogel. A floating HNG sample evaporated water with a record high rate of 3.2 kg m⁻² h⁻¹ via 94% solar energy from 1 sun irradiation, and 18–23 litres of water per square metre of HNG was delivered daily when purifying brine water. These values were achievable due to the reduced latent heat of water evaporation in the molecular mesh under natural sunlight.

产生太阳蒸气是一种收集太阳能以净化污染水或盐水的有效方法。然而，水蒸发受太阳能利用效率低下的困扰或依赖于复杂且昂贵的聚光配件。在这里，我们演示了基于聚乙烯醇（PVA）和聚吡咯（PPy）的分层纳米结构凝胶（HNG），该凝胶可用作独立的太阳能蒸汽发生器。转换后的能量可以原位用于为PVA网络的分子网中所包含的水的蒸发提供动力，其中水凝胶的骨架可促进水的蒸发。浮动的HNG样品蒸发水的速度达到了创纪录的3.2 kg m ^-2  h ^-1通过1次太阳照射产生的94％的太阳能，净化盐水时，每天每平方米HNG输送18-23升水。由于在自然阳光下分子网中水蒸发的潜热降低，因此可以实现这些值。