Nature-inspired salt resistant polypyrrole–wood for highly efficient solar steam generation

Abstract

Solar steam generation has emerged as a promising and sustainable method of addressing the water shortage issue. Although various materials and structures have been reported, designing a highly efficient steam generation device with excellent salt resistant performance remains a great challenge. For the first time, a polypyrrole (PPy)–wood device has been prepared through a simple “soak and polymerization” process by in situ polymerization of pyrrole monomers into a three-dimensional (3D) porous wood matrix. The PPy particles decorated on the wood matrix can convert incident light into heat while the 3D porous wood matrix can further enhance light absorption based on light harvesting and multiple scattering effects, which allows the PPy–wood light absorption to reach as high as 97.5% in the spectral range from 250 nm to 2500 nm. Owing to the low thermal conductivity of wood, the PPy–wood can localize the converted heat at the surface of the device, enabling efficient steam generation. The hydrophilicity and the numerous aligned microchannels of the PPy–wood ensure constant water supply to the air–water interface. All these merits endow the PPy–wood with a high solar energy conversion efficiency of 83% under 1 Sun, with an evaporation rate of 1.33 kg m⁻² h⁻¹. Moreover, the fabricated PPy–wood also shows good structure stability and cycling stability as well as excellent salt resistant performance. Benefiting from the low-cost of wood and the simple fabrication process, the PPy–wood with the above merits is one of the most suitable candidates for solar desalination.