Hollow Carbon Fiber Decorated by Nano Structure Surface for High‐Efficiency Water Steam Generation

Abstract

Utilization of carbon materials for harvesting solar energy is a green, feasible, sustainable, and promising way to manufacture freshwater from sewage and seawater. However, sunlight absorption efficiency, light to thermal conversion efficiency, and expensive cost are still limitations for large‐scale solar steam generation. Here, a solar steam evaporator which is fabricated by carbonized willow catkins films and activated by different metal chlorides under nitrogen at 800 °C is demonstrated. Under the light irradiation intensity of one sun (1000 W m−2), water evaporation rate of the prepared evaporator is up to ≈2.17 kg m−2 h−1, and the surface temperatures reach up to 50 and 91.7 °C under water‐saturated and dry situations, respectively, indicating good steam generation ability and heat localization performance of the fabricated evaporator. The SEM, BET, DSC, and ICP‐MS results show that such a high water evaporation rate of the prepared carbon materials is due to the typical tubular micro‐structure, which decreases water enthalpy of evaporation and the water evaporation in the form of molecular clusters. This method of carbonized and activated willow catkins films provides a sustainable way for efficiently harvesting solar energy to produce fresh water from seawater and sewage.

Carbon fiber coated by quinoa cellulose nanosheet with outstanding scaled salt self-cleaning performance and purification of organic and antibiotic contaminated water

“…It should be noted that evaporation rates of CFQC based evaporator are far beyond the theoretical value under the light intensity of 1000 W m −2 (1.592 kg m −2 h −1 , the detailed calculation process as shown in supplementary information), with apparent energy utilization rate over 100%, and those results seems unreasonable. But similar experimental phenomena have been observed in some previous literatures, such as polyvinyl alcohol (PVA) based evaporators 19 , 53 , 54 , self-blacking cellulose and graphene oxide composite gel 41 and hollow carbon fiber 13 have the higher evaporation rate than that of theoretical under one sun, where a water clusters based evaporation have been proposed and can be well elucidate the phenomenon of beyond the biggest value 53 – 55 .…”

“…The challenges of energy and clean water scarcity, especially in the remote areas, are becoming a more and more serious issue and would severely influence on economic and society development 1 , 2 . Currently, many technologies have been proposed to solve these problems 3 – 5 , for instance reverse systems 6 , 7 , multi-stage flash 8 , 9 , adsorbed treatment 10 , tiny-fog collection 2 , 11 , 12 and interface solar assisted evaporation 13 , 14 , among which solar assisted evaporation is regarded as a promising strategy to address the fresh water scarcity by treating the seawater on account of its economically, easy operation, renewable energy sources, sustainability and environment friendliness 15 , 16 . The biggest advantage of interfacial evaporation is high solar energy utilizing efficiency which attributes to its excellent energy management by remarkably suppressing heat loss to bulk water via thermal insulation foam between the bulk water and work interface, and good water management enabled by hydrophilic properties of photo-thermals conversion materials 13 , 17 – 19 .…”

“…Additionally, some new advanced technology has been introduced in solar steam generation field to enhance the water evaporation efficiency 31 – 35 , such as atomic layer deposition (ALD) 31 technology, Janus materials fabricating technology 30 , 32 , 33 , 36 , piezoelectric and solar steam synergistic technology 35 , 37 and photovoltaic and solar steam generation synergistic technology 23 , 38 . For photo-thermal conversion materials, carbon materials have attracted largely interests in virtue of its excellent chemical stability, thermal stability, broadband absorption of solar lights, and extensive sources from nature and industrial goods 13 , 39 – 41 . Carbon fiber (CF) as commercial products with the performance of “light and strong” is widely used in advanced composites materials (aerospace, military, sports, automobile and others applications) due to its excellent properties, including low density, outstanding mechanical properties, corrosion resistance, creep resistance, chemical stability, good thermal conductivity, and peculiarly good adsorption of sunlight 42 – 45 .…”

A carbonized carbon dot-modified starch aerogel for efficient solar-powered water evaporation

“…10,11 To realize a high photothermal-conversion efficiency, many efforts have been made to develop efficient solar water evaporators. [12][13][14][15][16][17][18][19][20][21] Recently, biomass-based evaporators have attracted increasing attention due to some unique advantages, such as an inherent porous structure, [22][23][24][25] the potential to form hydrogels, 26 environmental friendliness and low cost. 27,28 Nevertheless, the further design and optimization of the inherent porous structure of biomass-derived evaporators would be restricted.…”

A Simple, Scalable, Low‐Cost Honeycomb‐Like Carbonized Corncob for Highly Efficient Solar Steam Generation

“…A satisfactory STCM should have the following characteristics: 1) high solar absorption within a broadband wavelength range (the entire solar spectrum); 2) high light-to-heat conversion; 3) low thermal conductivity; 4) good hydrophilicity; 5) convenient porous channels; 6) good salt-resistant performance. [7][8][9][10][11] At present, STCMs mainly include metal particles, [12] semiconductors, [13] carbon materials, [14][15][16][17][18][19][20] natural materials, [21][22][23][24][25][26][27][28][29][30] and so on. Scholars have made a lot of explorations on different materials.…”