Low‐Cost, Scalable, and Reusable Photothermal Layers for Highly Efficient Solar Steam Generation and Versatile Energy Conversion

Abstract

absorption with noticeable photothermal conversion efficiency have been developed for SSG, [7,8] plasmonic metal, [9][10][11][12][13] semiconductors, [14][15][16][17] and carbon-based materials. [18][19][20][21] However, the high-cost and complex manufacturing processes make it hard to prepare on a large-scale. [22] And the accumulation of salt deposits on the photothermal layers results in a sharp decline in SSG performance, thus lacking sustainability and recyclability. [23] Therefore, the SSG are yet far from industrialization that requires low-cost, scalable, and reusable photothermal materials.Carbonization of rampant plants into carbon materials by the high-temperatureinduced pyrolysis provides an alternative solution to these problems, but it still has great challenges. [24] With the development of this technology, a variety of plants have been explored to synthesis different photothermal layers. [25][26][27][28][29] For instance, Xu et al. [28] demonstrated mushrooms as a solar steam generator for the first time. The unique natural structure of mushroom, porous context, and fibrous stipe, make the conversion efficiency of natural and carbonized mushrooms achieve 62% and 78% under 1 sun illumination. Fang et al. [29] found that the unique macroscopic cone shape and hierarchical porous structures of the carbonized lotus seedpods resulted in an evaporation rate and the corresponding evaporation efficiency under 1 sun irradiation of 1.30 kg m −2 h −1 and 86.5%, respectively. The special structure of plant stem is conducive to improving the SSG ability, which is due to the fact that the plant stem can transport water and other nutrients to the upper layer during the whole plant growth process. [30] However, the prices of the current plants, such as mushroom, lotus seedpods, still need to be further cut down (the cost comparison is shown in Table S1 in the Supporting Information). It is of great significance to explore more abundant and low-cost plants for carbonization. Moreover, the mechanical strength and surface of the plants are destroyed by the high temperature during the carbonization process. It is still a big challenge to uniformly and stably deposit the carbonized species on substrates or assemble them to self-stand films at a large scale. [31][32][33] Most importantly, the steam generation rate and evaporation efficiency are yet to be further increased. Solar steam generation (SSG) based on the photothermal effect has beenconsidered to be a promising avenue for freshwater production. However, the fabrication of highly-efficient photothermal layers, at large-scale and low-cost is still a challenge, hindering practical applications. Herein, it is demonstrated that carbonized towel-gourd sponges (CTGS) are excellent photothermal materials. And a capillarity-driven interfacial self-coating method is developed to prepare the super-hydrophilic CTGS/paper photothermal layer. The SSG device based on the CTGS/paper exhibits a high evaporation rate of 1.53 kg m −2 h −1 with an efficiency of 95.9% under 1 sun i...

A Low‐Cost 3D Spherical Evaporator with Unique Surface Topology and Inner Structure for Solar Water Evaporation‐Assisted Dye Wastewater Treatment

“…In recent years, solar steam generation has drawn much attention due to its potential applications in desalination, [ 1 ] wastewater treatment, [ 2 ] and power generation. [ 3 ] Various 2D solar evaporators with excellent light absorption, [ 4 ] low heat conduction loss, [ 5 ] salt‐rejecting property, [ 6 ] stability, [ 7 ] and low cost [ 8 ] have been designed. However, inevitable energy loss such as reflection and radiation, enabled the evaporation efficiency of 2D solar evaporators to reach its upper limit.…”

Concentrated Acid‐Induced Dehydration of Fallen Leaves for Efficient, Sustainable, and Self‐Cleaning Solar Steam Generation

“…Biomasses, such as wood, [ 27 ] mushroom, [ 28 ] lotus seedpods, [ 29 ] kelp, [ 30 ] and towel‐gourd sponges [ 31 ] are renewable resources, which provides stable and abundant supplies for synthesis of carbon materials. Various carbon materials are obtained by pyrolysis or carbonization of biomasses for solar‐driven water evaporation.…”

Spectrum Tailored Defective 2D Semiconductor Nanosheets Aerogel for Full‐Spectrum‐Driven Photothermal Water Evaporation and Photochemical Degradation

“…The excellent wettability is conducive to water flow and vapor escaping. [ 5h,9 ] Figure 4c shows the Q s of the aerogels, which display similar values of ≈11 g g −1 due to their analogous structure (Equation S2, Supporting Information), implying a high swelling capacity. By recording the swollen time from half‐saturated state (0.5Q s ) to saturated state, the T values of the aerogels are determined to be around 5 min (Figure S10, Supporting Information).…”

“…[8] Also, it is relatively low-cost and solution based massproducible, critical towards practical application. [9] Through the ingenious integration of D-HNb 3 O 8 with PAM, the constructed hybrid aerogel inherits both the desirable properties and structural merits of the respective building blocks. Specifically, the D-HNb 3 O 8 absorbs the full solar spectrum to perform two disparate spectrally selective functions of UV-driven photocatalytic excitation and visible-NIR induced photothermal heating.…”

“…[ 8 ] Also, it is relatively low‐cost and solution based mass‐producible, critical towards practical application. [ 9 ]…”