Fig. 1.

Solar vapour gap membrane distillation (SVGMD): enabling concept, key features, and operational principle. a–c Summary of the key features: a free-standing light absorber consisting interconnected skeleton and light-absorbing nanomaterials; b formation of thin water layer with self-suction and localized heating. c Solar vapour in the gap which separates the membrane from the water. d Schematic of SVGMD. Superhydrophilic light absorber ensures fast water suction. Under solar illumination, localized heat transfer leads to the efficient generation of solar vapour in the gap, which passes through the membrane and condenses with the distillate flow. e The SVGMD concept and scalable water purification system with high solar-water energy efficiency, excellent anti-fouling performance, and stable permeate flux