Highly Efficient Solar Steam Generation under Low Solar Flux via Carbon‐Nanotube‐Modified Sugarcane

Solar steam generation is considered as one of the most promising technologies for water desalination. The key to its widespread application is to achieve a simple, scalable, and cost‐effective method to fabricate a high‐performance solar–thermal material under low solar flux conforming to the real conditions. Herein, inspired by the unique structure of natural sugarcane, a novel strategy is demonstrated to construct a solar–thermal material composed of carbon nanotubes and sugarcane for solar steam generation. The carbon nanotube layer provides a blackbody‐like high solar absorption and the sugarcane simultaneously serves as the thermal insulator and water channel due to the honeycomb structure with closed/open pores and the excellent hydrophilicity. Based on these, this as‐prepared absorber could achieve an evaporation rate of 1.65 kg m −2 h −1 and a conversion efficiency up to 94.2% under 1 sun illumination, comparable or even higher than most of the reported solar steam generation devices. Significantly, the efficiencies are all above 88.9% even under the low solar flux (<1 sun), surpassing those of other reported solar steam generation devices under ambient conditions. Such a sugarcane‐inspired design could provide a low‐cost and scalable solution to the pressing global clean‐water‐shortage problem.