Solar energy holds great promise for sustainable desalination to alleviate global water scarcity. Recently developed solar steam generation relying on interfacial evaporators has high solar energy-to-steam efficiency (60–90%), but its vapor collection efficiency is low, typically ~30%. Here, we present a solar-driven photothermal membrane distillation (PMD) system that offers easy and highly efficient clean vapor generation, condensation, and collection. The new photothermal membrane is thermally-engineered to incorporate a bilayer structure composed of two environmentally-sustainable materials, polydopamine (PDA) particles and bacterial nanocellulose (BNC), and it achieved a permeate flux of 1.0 kg m⁻² h⁻¹ under 1 sun irradiation and a high solar energy-to-collected water efficiency of 68%. The thermally-engineered strategy of using a bilayer structure ensures superb optical/photothermal activities, maximized membrane porosity (~93%), and reduced conductive heat transfer, thus increasing the thermal efficiency of the membrane. The strong chemically-bonded fluorosilane functional groups on the membrane surface provide stable hydrophobicity and high salt rejection (>99.9%). Moreover, under solar irradiation, the membrane shows effective interfacial photothermal disinfection to kill bacteria, enabling easy cleaning and increasing its lifespan. Using solar energy, the PMD system presented here can provide advantageous decentralized desalination for remote areas, and can support resilient community development.

太阳能有望实现可持续的海水淡化以减轻全球水资源短缺。最近开发的依靠界面蒸发器的太阳能蒸汽产生具有较高的太阳能转化效率（60-90％），但其蒸汽收集效率很低，通常约为30％。在这里，我们介绍了一种太阳能驱动的光热膜蒸馏（PMD）系统，该系统可提供简单高效的清洁蒸汽生成，冷凝和收集功能。新型光热膜经过热工程处理，结合了双层结构，该双层结构由两种环境可持续性材料（聚多巴胺（PDA）颗粒和细菌纳米纤维素（BNC））组成，渗透流量为1.0 kg m ^-2  h ^-1在1个阳光照射下，太阳能集热效率高达68％。使用双层结构的热工程策略可确保出色的光学/光热活动，最大化的膜孔隙率（约93％）和减少的传热，从而提高了膜的热效率。膜表面上牢固的化学键合的氟硅烷官能团可提供稳定的疏水性和高除盐率（> 99.9％）。此外，在太阳辐射下，该膜表现出有效的界面光热消毒作用，可以杀死细菌，从而易于清洁并延长其使用寿命。使用太阳能，这里介绍的PMD系统可以为偏远地区提供有利的分散式海水淡化，并可以支持弹性社区发展。