Surface‐Carbonized Bamboos with Multilevel Functional Biostructures Deliver High Photothermal Water Evaporation Performance

Abstract

Interfacial solar steam generation (ISSG) has attracted global attention as an important approach for water purification and desalination. The related photothermal materials based on 3D biostructures are promising due to their abundance and easy accessibility. Here, it is shown that surface‐carbonized bamboo (SC‐bamboo) as a photothermal material exhibits outstanding ISSG performance due to its multilevel functional biostructures. On a microscopic scale, the bamboo's air‐filled parenchyma cells promote thermal insulation while its vascular bundles ensure rapid water transport. On a macroscopic scale, a unique concave structure at the bamboo nodes concentrates water and heat in a confined region and the air‐filled hollow chambers in bamboo internodes also ensure thermal insulation. These multilevel functional structures of SC‐bamboo result in a solar‐thermal conversion efficiency up to 93.63% ± 1.57% under 1 kW m−2 irradiation, surpassing most biomass‐derived materials ever reported. Considering bamboo's low cost and convenience, this work sheds light on the design and fabrication of readily accessible, multilevel functional structure for efficient photothermal‐conversion devices.

Ultrablack Poly(vinyl alcohol)‐Graphite Composite Xerogel with Vertically Arranged Pores for Highly Efficient Solar Steam Generation and Desalination

“…The vertically arranged pore structures of the PGCXs are similar to vascular bundles found in many plants and help improve the water transport capacity and solar steam generation performance. [58,59] PGCXs are superhydrophilic and have high water transport rates. As shown in Figure 2c, take the PGCX-50% for example, when the PGCX-50% was placed vertically, water can be quickly transported from the bottom to the top.…”

A Stable Bilayer Polypyrrole‐Sorghum Straw Evaporator for Efficient Solar Steam Generation and Desalination

“…In recent years, some natural biomass porous materials have been used as solar evaporators due to abundant reserves, low cost, low density, low thermal conductivity, recyclability, non-pollution to the environment, and unique open-cell structure. [21,23,[42][43][44][45][46][47] Liu et al [44] successfully prepared a bilayer evaporator by carbonizing the surface of the bamboos. Sun et al [46] also successfully constructed a bilayer evaporator by coating a multi-walled carbon nanotube and titanium dioxide composite on the cross section of corn stalks.…”

“…In recent years, some natural biomass porous materials have been used as solar evaporators due to abundant reserves, low cost, low density, low thermal conductivity, recyclability, non‐pollution to the environment, and unique open‐cell structure. [ 21,23,42–47 ] Liu et al. [ 44 ] successfully prepared a bilayer evaporator by carbonizing the surface of the bamboos.…”

“…[ 21,23,42–47 ] Liu et al. [ 44 ] successfully prepared a bilayer evaporator by carbonizing the surface of the bamboos. Sun et al.…”

Natural Porous Materials for Interfacial Solar Steam Generation toward Clean Water Production

“…[50][51][52][53] However, at the same time, the naturally found porous materials often provide relatively lower solar absorbance, which has been addressed by providing an extra layer of coating using nanomaterials [54][55][56] or chemical treatment [49,57,58] and carbonization of the materials. [36,55,[59][60][61] Among many natural porous materials, wood, [62][63][64][65][66][67][68] mushroom, [60,69] straw, [55] radish, [70,71] corncob, [72,73] bamboo, [47,51,74,75] lotus seedpods and leaf, [59,76] carrot, [77,78] sunflower head, [79,80] luffa sponge, [49,81,82] coconut husk, [83] rice husk, [84,85] etc. are the most commonly investigated natural porous materials for the ISSG-based system.…”