Tunable Water Delivery in Carbon-Coated Fabrics for High-Efficiency Solar Vapor Generation

Abstract

Solar vapor generation by localized heating and evaporation has potential to be a viable and “green” way to produce fresh water. This work reports a carbon black-coated cotton fabric with a tunable water delivery property for high-efficiency solar vapor generation under 1 sun. The fabric is prepared by an electrospray of poly­(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) on one-side of the fabric followed by dip-coating of the fabric with carbon black as a photothermal absorber. Depending on the duration of electrospray, the roughness gradient generated by the PVDF-HFP layer in the fabric leads to guided and continuous one-way water transport from the electrosprayed hydrophobic side to the hydrophilic side with a tunable delivery rate. The tunable water delivery capability of the fabric regulates the amount of water supplied to the vicinity of the photothermal absorber. Additionally, the fabric shows excellent broadband absorption and low thermal conductivity. In comparison with the carbon black-coated fabric without a roughness gradient, the regulation of water improves the solar vapor conversion efficiency, owing to reduced heat loss and better heat allocation. Under optimal conditions, a solar vapor conversion efficiency of 88.9% and a stable water evaporation rate of 1.33 kg (m2·h)−1 under 1 sun are achieved.

Nature Inspired MXene-Decorated 3D Honeycomb-Fabric Architectures Toward Efficient Water Desalination and Salt Harvesting

“…The value is much higher than that of all previously reported MXene-based and fabric-based evaporators and the evaporation rate and evaporation efficiency are among the highest of all solar absorbers (Fig. 4f and Table S1) [11,34,36,38,55,[57][58][59][60][61][62]. This result demonstrates the advantage of a honeycomb structure in energy utilization.…”

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

“…As confirmed previously, the moderate hydrophilicity of photothermal film can further reduce heat loss and improve water evaporation efficiency. [ 49 ] To further improve the hydrophilicity of the photothermal film, the 80FLPD6‐MCEP was treated by oxygen plasma. The contact angle of the treated film (80FLPD6‐MCEPO 2 ) is reduced to 49°.…”

Sunlight‐Responsive Photothermochromic Fabric with Reversible Color Changing Based on Photothermal Conversion

“…Commonly, the surface of carbon black shows the amino resin (CH), carbonyl group (C═O), and the amido bond (NH 2 ) due to the oxidation effect. [ 20 ] It can be characterized by the absorption peaks of the sunlight‐responsive heating paste at 820, 1710, and 1170 cm −1 respectively.…”

“…[17][18][19] The strong absorptance of carbon materials in the spectrum relevant to solar radiation, in combination with the low cost and commercial availability of the material, makes it good choice as a photothermal absorber. [20][21][22] However, the temperature of the sunlightresponsive heating fabric is proportional to the irradiation power density of solar, and the high temperature generated by photothermal conversion will bring great risk of scald to the human body. [23] Therefore, it is imperative to develop novel sunlightresponsive heating fabric with sensitive temperature-monitoring functions.Thermochromic textiles present reversible color changing in response to the variation of external temperature and have shown various potential applications, such as temperature indicators, wearable electric devices, health monitoring, and military camouflage.…”