Robust aerogels based on conjugated microporous polymer nanotubes with exceptional mechanical strength for efficient solar steam generation

The creation of a porous medium with high solar energy harvesting and conversion efficiency as well as desired robustness is essential for construction of an efficient solar steam generation system. Herein, we report the first example of conjugated microporous polymer (CMP) aerogel-based solar steam generators, which were synthesized by using 1,3,5-triethynylbenzene, 1,4-dibromobenzene and 4,4-dibromobiphenyl as building blocks through Sonogashira-Hagihara cross-coupling reaction. The resulting CMP aerogels show high porosity of greater than 94%, owing to their porous three-dimensional network architecture which is constructed by CMP nanotubes with diameters of ca. 100 nm. The CMP aerogels possess low thermal conductivity (0.022 W m(-1) K-1) and exceptional mechanical properties with a compressive strength of up to 0.54 MPa under loading of 75% strain. Solar steam generation efficiencies of up to 81%, 85% and 88% are achieved at light intensities of 1 kW m(-2), 2 kW m(-2) and 3 kW m(-2), respectively. The findings of this study may provide a new opportunity for rational design and construction of new CMP-based solar steam generators due to the designable flexibility of CMPs which makes it possible to fine tune both porosity and chemical composition of the resulting CMP product only by varying the CMP building blocks through a simple one-pot reaction.