Vertically aligned Juncus effusus fibril composites for omnidirectional solar evaporation

Despite tremendous efforts to improve solar-driven steam generation, most solar evaporators are limited to unidirectional evaporation due to changes in the direction of solar irradiation under real-world conditions. Hence, the development of non-unidirectional evaporators, ideally allowing omnidirectional evaporation, remains a significant challenge. In this work, the first-ever vertically aligned activated carbon–juncus effusus (AC-JE) evaporator (VACJE) for omnidirectional evaporation is demonstrated. AC-JEs are produced by uniformly decorating activated carbon powder (a cost-lost material with broad efficient solar absorption) on the fibril skeletons of JE with interconnected network architectures. The surprising photothermal performance (the evaporation rate of 2.23 kg m−2 h−1 under 1 sun illumination) of the VACJE is attributed to the unique inbuilt interconnected network architecture of JE. This structural feature multiplies the available evaporation area to promote omnidirectional solar evaporation, while also providing excellent light absorption thermal management and salt-resistant. This unexpected finding reveals the hidden potential of JE as a low-cost biomass material and provides inspiration for the future design and development of high-performance solar-driven steam generators.