Bamboo decorated with plasmonic nanoparticles for efficient solar steam generation

Natural bamboo has become a new kind of substrate for photothermal material to apply in solar steam generation due to the advantages of oriented microchannels, thermal insulation, hydrophilia, fast-growing, low-cost, and renewability. However, natural bamboo without photothermal conversion materials cannot be directly applied to solar steam generation because its optical absorptivity is low. Fortunately, plasmonic metal materials have high optical absorptivity and can be obtained on the surface of bamboo by chemical synthesis. Herein, plasmonic bamboo with low thermal conductivity was manufactured by a solution method to realize heat localization for solar steam generation. Plasmonic metal nanoparticles were uniformly deposited on the surface of the oriented vessels to form the structure of photothermal conversion. Oriented microchannels of bamboo can transform the light path by the waveguide effect and continuously transport water by the capillary effect. Meanwhile, the plasmonic effect causes high light absorption. Therefore, plasmonic bamboo demonstrated that the maximum light absorption could exceed 99% in the wavelength range of 250–2500 nm. Overall, the plasmonic bamboo showed a high conversion efficiency of 87% under a ten-sun illumination (the solar flux is 10,000 W m−2) and excellent cycling stability with no degradation after 140 h of cycling under five suns (the solar flux is 5000 W m−2). The plasmonic bamboo device is a potential candidate for efficient steam generation without any support system.