Article pubs.acs.org/cm
Reduced Graphene Oxide−Polyurethane Nanocomposite Foam as a Reusable Photoreceiver for Efficient Solar Steam Generation Gang Wang, Yang Fu, Ankang Guo, Tao Mei, Jianying Wang, Jinhua Li, and Xianbao Wang* Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Key Laboratory for the Green Preparation and Application of Functional Materials, Ministry of Education, Hubei Key Laboratory of Polymer Materials, School of Materials Science and Engineering, Hubei University, Wuhan 430062, China S Supporting Information *
ABSTRACT: Solar steam generation driven by local hot spots is an efficient route to use solar energy. We introduce a novel photoreceiver composed of reduced graphene oxide (rGO) and polyurethane (PU) matrix for highly efficient solar steam generation. The rGO nanosheets covalently cross-linked to PU matrix provide excellent stability and broad optical absorption, together with the property of thermal insulation served by PU resulting in rapid increase of local thermal under illumination. Moreover, the hydrophilic segments and the interconnected pores of rGO/PU can be worked as water channels for replenishment of surface water evaporated. With excellent mechanical and chemical stability, the functional rGO/PU foam exhibited a solar photothermal efficiency of ∼81% at a light density of 10 kW/m2. The novel macro design demonstrated here is low cost, simple to prepare, and highly stable, being suitable for a series of practical applications in massive seawater desalination, solar steam generation, and sterilization of waste.
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INTRODUCTION
can also realize the highly efficient conversion of solar energy and effective seawater desalination.13,14 In 2013, gold nanoparticles were first reported to induce dramatic localized heating under laser illumination for the solar steam generation at a relativity low temperature.15 After that, various heat localization nanomaterials and structures have been proved to significantly improve the evaporation efficiency, including noble-metal nanofluids16,17 and their macroassembled layers18 and carbon-related nanofluids19 and their macro designs.20 A clear trend can be concluded that low cost materials and floating macro designs attracted more attention.21,22 The characteristics of low cost, simple preparation suggest great prospects and potential for application in modern industrialization. The floating macro designs can restrain the absorbed solar energy in a thinner region to decrease dissipated heat to the bulk water. So far, the nonprecious metal materials have been explored to absorbed solar energy including titanium nitride,23 titanium oxide,24 graphene,25,26 etc. The macro designs mainly depend on the deposition or assembly of nanoparticles onto different membranes such as anodic aluminum oxide membrane, mixed cellulose membrane, and air-laid paper.27−29 Impressive high evaporation efficiency and low-cost macro designs have been achieved, but only for a
Adequate fresh water is the magnitude guarantee of the living and development of human being. However, more and more cities and regions are facing the problem of shortage of fresh water.1 Presently, over one-third of the world’s population lives in water shortage region, and this number is rising shown as in relevant statistic date; therefore, it is imperative to search for an energy-saving and efficient way to make fresh water.2 The technology of seawater solar desalination seems to be a brilliant solution to tackle this urgent problem.3,4 First, the abundant seawater resource ensures an immense, constant production of potable water, without weakening natural freshwater ecosystems.2 Second, solar energy, as a kind of clean abundant and economical energy source, can effectively alleviate the pressure of energy shortage and reduce the negative impact of fossil fuel combustion.5,6 Traditional seawater desalination industry relies on thermal desalination, where the seawater is heated and the hot steam is condensed to obtain freshwater.7,8 This method suffers from low efficiency due to the requirement for heating the bulk liquid.9 Recently, a growing interest has been seen in using nanoparticles to enhance light absorption, turning it into an ideal nanoscale heat to achieve a range of applications.10,11 One of them is achieving local evaporation in a cold bulk water without heating the bulk liquid to a relatively high temperature to realize the thermal equilibrium of the steam and the whole liquid.12 The surface plasmon resonance effects of nanoparticles © 2017 American Chemical Society
Received: March 29, 2017 Revised: June 12, 2017 Published: June 12, 2017 5629
DOI: 10.1021/acs.chemmater.7b01280 Chem. Mater. 2017, 29, 5629−5635
Article
Chemistry of Materials limited amount of solution. Besides, these designs possess a relatively low mechanical stability and difficult fabrication processes.30,31 Thus, it is imperative that low-cost and stable heat-localization macro designs be introduced and used to achieve highly efficient solar steam generation. In this work, we introduce a reduced graphene oxide (rGO)−polyurethane (PU) nanocomposite foam (rGO/PU) for solar steam generation through converting solar energy into nanoscale heat at the evaporated surface. The rGO/PU was synthesized by the reaction of diisocyanates, polyether, and polyethylene glycol (PEG) directly inside the dimethylformamide (DMF) dispersion of graphene oxide (GO), followed by the high temperature foaming and chemical reduction. PU foam is a highly attractive material with diverse industrial application due to its abundant microporous structure, excellent thermal insulation properties, and facile and scalable synthesis. Here, we use the oxygen containing groups on the GO sheets surface, such as hydroxyl and carboxyl groups to react with the isocyanate groups to form stable chemical bonds. Then, the method of in situ growth was used to obtain the GO−PU nanocomposite foam (GO/PU) and ensure the uniform dispersion of GO in the nanocomposite foam. Due to the modification of hydrophilic segments and the existence of interconnected pores, coupled with the self-floating capacity of the functional foam, this macro design can achieve the state of semiwet under illumination, which can improve the evaporation efficiency via the separation of water from bulk water. With the characteristics of high optical absorption, low thermal conductivity, effective water transmission, and the capacity of self-floating, the macro design can be an attractive material for efficient solar steam generation. Moreover, the functional foam exhibited excellent stability due to the covalent bonds formed between GO and PU matrix. The current contribution offers the opportunity for the application in modern energy, seawater desalination, environmental improvement, etc.
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Figure 1. Schematic illustration showing the fabrication of rGO/PU and setup for solar steam generation using the rGO/PU. Characterization. The morphologies of rGO/PU were observed by field-emission scanning electron microscopy (SEM; JSM7100F, Japan). GO and the reaction product of GO and TDI were investigated by Fourier transform infrared (FT-IR) spectra (NICOLET iS50, USA). The contact angles of a series of PU were recorded with a standard contact-angle analyzer (PT-705-A, Pusite Detection Equipment Co., Dongguan, China). The optical transmission and reflectivity spectrum of GO/PU and rGO/PU are measured by a Shimadze UV−vis−NIR UV3600 double beam spectrophotometer with date reaction system mode. The simulated natural sunlight was generated by a xenon lamp (CEL-HXF300, Education Au-light Co., Beijing, China). Solar Steam Generation. In order to verify the optimal amount of GO in the composites, we compared the photothermal conversion ability of different samples including water, PU foam, and several GO/ PU with different amount of GO under irradiation. The solar irradiation was simulated on the basis of a white-light source by a solar simulator xenon lamp with a light density of 3 kW m−2. During a certain time irradiation, the mass of water in the beaker was recorded by an electronic balance. The beaker wrapped by polystyrene foam as a heat-insulating wall to reduce thermal losses. The weight changes of water of different samples can be calculated accordingly. In order to compare the photothermal conversion of GO/PU and rGO/PU, the weight change of water with above samples was recorded using the real-time system at the light density of 1 and 10 kW m−2. We selected a series of optical concentrations to illuminate the rGO/PU for 30 min and record the weight of water with rGO/PU following the change of time. The steam generation process of rGO/PU was measured by recording the mass change as a functional of time, and the examination of solar steam generation was cycled for 20 times under the same experimental conditions to confirm the reusability and stability of the design. For each cycle, rGO/PU was illuminated under a white-light source by a solar simulator xenon lamp with a light density of 1 kW m−2. After 20 min, the wetted rGO/PU was dried in a vacuum oven and arranged for next repeat.
EXPERIMENTAL SECTION
Materials and Methods. 2,4-Tolylene diisocyanate (TDI, 99%), ditin butyl dilaurate (95%), and triethanolamine (99%) were supplied by Aladdin Industrial Inc., China. Polyether triols (N330, Mn = 3000), PEG (Mn = 200), and DMF were obtained from Shanghai FangYe Chemical Co., Ltd. GO was purchased from Suzhou HengQiu Graphite Technology Co., Ltd. L-Ascorbic acid (99.7%) was provided from Chinese Medicine Group Chemical Reagent Co., Ltd. Polydimethylsiloxane was supplied by Shanghai Gonghang Chemical Co., Ltd. All the chemicals were of analytical grade and used as received. Synthesis of rGO/PU. The procedure for preparing rGO/PU is presented in Figure 1. First of all, 40 mg of GO was dispersed in 4 mL of DMF with the assist of ultrasonication at 20 °C. Then, 4.56 g of N330, 2.28 g of PEG, 0.2 mL of deionized water, and 0.07 g of polydimethylsiloxane were added into the above GO suspension in the presence of ditin butyl dilaurate (0.2 wt %) as a catalyst (for determination of the amount of PEG, see Supporting Information Figure S1), and a glass rod was used to mix the hybrids evenly. Afterward, 4.35 g of TDI and 0.03 g of triethanolamine were added into the beaker, and the admixture was stirred until thickened. Second, the admixture was poured into a mold made from paper and stored in an oven at 75 °C for 0.5 h to in situ prepare GO/PU. Finally, rGO/PU was prepared by the method of chemical reduction with the assistance of microwave. Briefly, the as-prepared GO/PU was placed in a 200 mL beaker containing 50 mL of 2 mg/mL L-ascorbic acid aqueous solution. This beaker was then seated in a microwave reactor (Sineo, MAS-IIPlus, China) operating at 300 W and 95 °C over 8 min. After microwave irradiation, the product was taken out and washed for several times with deionized water, giving the stable rGO/PU.
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RESULTS AND DISCUSSION Synthesis and Characterization of Hydrophilic rGO/ PU. Graphene, a honeycomb-shaped thin film material, is formed by using sp2 heterozygous carbon atoms into keys, which exhibits attractive optical, electrical, and mechanical characteristics.32,33 While single layer graphene is an excellent transparent material, the multilayer graphene exhibits outstanding ability of light absorption from the visible to nearinfrared (NIR) region of solar spectrum and desirable photothermal conduction. So we can infer that graphene can be an attractive candidate for the rapid generation of solar steam if a novel macro composite material can be designed to stabilize the multilayer graphene at the surface of the water and expedite the water to the photothermally active region. However, it is difficult for graphene to form a durable 5630
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Figure 2. (a) Proposed reactions during the isocyanate treatment of GO. (b) FT-IR spectra of GO and isocyanate-treated GO.
Figure 3. (a) Transmittance and (b) reflectance of GO/PU and rGO/PU in the wavelength range of 300−1500 nm.
Figure 4. (a,b) SEM images of PU. (c,d) SEM images of rGO/PU.
for the interface design of GO and polymer matrix.34,35 Here, TDI was used to treat with GO, of which the carboxyl and hydroxyl groups can lead to the chemical cross-linking between GO and PU matrix via formation of amides or carbamate esters, respectively (Figure 2a). Then, GO/PU was obtained via the method of in situ thermal polymerization, which successfully solved the major problems of poor dispersion and weak
composite material with other compound due to the chemical stability. GO, as one of the most significant derivatives of graphene, has similar optical, electrical, and thermal characteristics. Therefore, GO exhibits attractive chemical activity due to the availability of various chemical groups such as epoxy and hydroxyl functional groups in the basal planes, and carbonyl and carboxyl functional groups at the edges, which can be used 5631
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Figure 5. Thermal conductivity of (a) wet PU and (b) wet rGO/PU are measured by the IR camera method. The inset in the figures are the representative picture of temperature gradient along the thickness of the wet PU and rGO/PU.
interface between graphene and polymer matrix. The chemical interaction of GO after treatment can be observed by FT-IR spectroscopy (Figure 2b). The red curve in Figure 2b displays the characteristic peaks of GO and the black curve shows the characteristic peaks of the derivatives of GO (iGO, GO, and its derivatives were washed with plenty of water, filtered, and dried under vacuum). Both GO and iGO show the stretching vibration of CO carbonyl groups (1726 and 1663 cm−1). However, a new stretch at 1530 cm−1 can be observed after treatment, which is a result of the C−N stretching vibration. This result shows that iGO was successfully grafted with amides or carbamate esters. The FT-IR spectra of GO derivatives do not show signals related to the −NCO isocyanate group (2275−2263 cm−1), illustrating that the reaction of GO with TDI results in chemical reactions and not mere absorption/ intercalation of the organic isocyanate. We recently demonstrated that rGO had a stronger ability to convert light to heat than GO due to its enhanced optical absorption.36,37 rGO/PU also have higher optical absorption ability than GO/PU, the results are shown in Figure 3. The optical transmission spectrum of the GO/PU and rGO/PU are measured in the wavelength range of 300−1500 nm. Both GO/ PU and rGO/PU showed nearly 5% optical transmittance and the transmittance of rGO/PU was slightly lower than that of GO/PU from visible to near-infrared regions. The reflectivity of the rGO/PU was detected with a UV spectrophotometer, and it was about 4%, which was also lower than that of GO/PU. Thus, about 91% of the irradiated sunlight can be absorbed by the rGO/PU. Investigation on the dispersion level of the rGO in the PU matrix and the structure of rGO/PU composites is important to understand the improvement in the ability of photothermal conversion. Because the uniform dispersion of rGO and the connected open cell structure of rGO/PU are the decisive factors affecting solar energy absorption and liquid supply. The SEM images shown in Figure 4 reveals that both PU and rGO/ PU contain abundant open porous structures, which can be worked as water channels for replenishment of surface water evaporated. From the different morphologies of PU and rGO/ PU, it can be seen that the surface of PU is smoother than rGO/PU, and the formation of coral-like rough structure is due to the successful graft of functionalized rGO sheets to PU matrix. Besides, Figure 4d rendered stable and homogeneous distributed rGO in foam surface without congregation as an indication of the fine dispersion of rGO in PU matrix. With the rough and porous surface structure to enhance multiscattering, rGO/PU possess a stronger solar absorption.
The thermal conductivities of PU and rGO/PU were explored under wet condition. Since the rGO/PU is in a hydrated state during evaporation, it is more valuable to get the thermal conductivity of the foam in the wet state. The temperature changes of the samples were record by an IR camera (Figure 5a,b, see details in Supporting Information). The result showed that the thermal conductivity of the wet PU was 0.5182 W m−1 K−1, which is lower than that of water (0.599 W m−1 K−1 at 20 °C). However, because of the remarkable thermal conductivity of rGO, the thermal conductivity of the wet rGO/PU (1.0984 W m−1 K−1) was slightly higher than that of water. The PU matrix with low thermal conductivity can help suppress local convection and contribute to focus the thermal energy by reducing the heat conduction from hot surface to the bulk water. Because the functional foam is in a state of semifloating in the water, the part near air is semiwet during the solar steam generation. The state of semiwet as well as the separation of PU matrix can promote the generation of local heat and the separation of surface water from bulk water under illumination. Efficiency Comparison. To illustrate the difference between the modified hydrophilic polyurethane foam (iPU) and hydrophobic polyurethane foam (oPU), the weight change through water evaporation for oPU under the solar illumination of 3 kW m−2 is measured and compared with iPU and pure water cases, as shown in Figure S2 (in addition to Figure S2, the rest of the article involving PU refers to iPU). The weight change of pure water over the duration of 1800 s was found to be 0.244 g. In the presence of the oPU, the weight change under identical irradiation conditions was found to be 0.099 g, which is less than half of pure water. However, the water evaporation weight of iPU was found to be 0.354 g, which is 1.45 times that of pure water. The results are due to that the oPU is buoyant on the water surface, and it can enormously limit the transfer of solar energy into the water. The reason for the different performances of iPU is its hydrophilicity, which promotes water flow to the top surface and leads to formation of a water sheet. When the iPU is exposed to light, the upper surface absorbs the solar energy and converts it into heat. Most of the heat is used to evaporate the water sheet on top of the absorber surface. The hydrophilic segments and interconnected pores of iPU can be worked as water channels for replenishment of surface water evaporated. In the process of evaporation and supplement of water, the state of semiwet is formed. The state of semiwet occurred at the top surface of photoreceiver can improve the evaporation rate via the separation of some water from bulk water. GO as the light absorbing material in the composite, its amount affects the evaporation efficiency and 5632
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Figure 6. Solar evaporation of different samples evaluated on the basis of the solar simulator with a light density of (a) 1 kW m−2 (optical concentration, Copt = 1), and (b) the temperature change of corresponding samples before and after solar illumination monitored by IR camera. Solar evaporation of different samples evaluated on the basis of the solar simulator with a light density of (c) 10 kW m−2 (optical concentration, Copt = 10), and (d) the temperature change of corresponding samples before and after solar illumination monitored by IR camera. (e) The evaporation efficiency and evaporation flux of the rGO/PU is compared with water and GO/PU under 1 and 10 kW m−2 solar illumination. The error bars of evaporation efficiency resulted from errors in the measurement of optical concentration and weight change, and the error bars of evaporation flux resulted from error in the weight change measurements. Photographs showing (f) that the functional foam is able to float on the water surface and (g) steam generation under simulated solar illumination.
1.7 °C, while the water temperature rise on the top surface of the beaker with the GO/PU and the rGO/PU reached 12.9 and 17.2 °C, respectively. The results show that both the rGO/PU and GO/PU have a strong ability to convert light to heat. However, the rGO/PU offers a better performance in enhancing the solar steam generation compared with GO/ PU, which is due to the stronger light absorption. Another fact can be observed that the vertical distribution of temperature of the beaker containing pure water is close to homogeneous after 30 min illumination, which shows a negligible temperature variation from top to bottom. However, both the beakers with rGO/PU and GO/PU showed a significant temperature gradient (∼11 °C). The upper layer was maintained at a relatively high temperature, while the lower layer almost kept at
structural stability of the composite. The details for determination of the optimum amount of GO is shown in Figure S3. In order to compare the capability of solar steam generation enabled by the GO/PU and the rGO/PU, the experiments on solar evaporation were conducted at a light density of 1 kW m−2 and 10 kW m−2. With the rGO/PU, the amount of water evaporated reached around 0.568 g after exposure to the 1 kW m−2 light source for 30 min, which is 1.16 times that of the GO/PU and 3.42 times that of pure water (Figure 6a). Meanwhile, IR photography was employed to record the temperature change during the experiment (Figure 6b). After solar illumination for 30 min, the water temperature rise on the top surface of the beaker containing only pure water reached 5633
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Figure 7. (a) Evaporation rate of rGO/PU under a range of optical density (right-hand side axis) and the corresponding evaporation efficiency of rGO/PU (left-hand side axis). (b) Weight change of evaporated water enhanced by rGO/PU versus cycle numbers under 1 kW m−2 solar illumination.
alkaline environment (pH = 10) for 24 h (Figur S4). The extreme environment does not impair the structural properties of the foam and the rGO sheets connected with PU matrix stably in the whole process. To further certify the reusability of rGO/PU, we tested the solar evaporation enhanced by rGO/ PU under the white-light source with a light density of 1 kW m−2, and the experiment of solar steam generation was conducted for 20 times under the same conditions (Figure 7b). For each cycle, after obtaining the weight change for 20 min of solar irradiation, the wetted rGO/PU was dried in a vacuum oven and arranged for next repeat. The measured results are linearly fitted to the straight line, which is approximately parallel to the X axis, all of the results are similar to the average of 0.94 g, and the macro morphology of rGO/PU has no change in the whole cycle. In summary, we have demonstrated the functional foam of rGO and PU matrix by in situ polymerization can effectively promote the generation of solar steam. Different from the conventional designs of optical absorption, the rGO/PU utilized the isocyanate groups to covalently cross-link GO nanosheets into nanocomposites, leading to the novel photoreceiver with excellent stability even under harsh chemical conditions. Owing to the modification of the hydrophilic segments and the existence of connected open cell structure, the functional foam could efficiently transport the fluid from bulk water to the illuminated surface. Moreover, with the characteristics of high optical absorption, low thermal conductivity, and excellent photothermal conversation, the rGO/PU exhibited a strong ability of solar steam generation. The current finding should offer the opportunity to develop high-performance and high stability material for solar steam generation and extend the applications of GO/PU composites.
the state before illumination. Therefore, efficient light absorption and localized heating at the air−water interface can enhance the solar energy utilization and solar steam generation. At the density of 10 kW m−2, the samples showed similar performance (Figure 6c,d). To systematically analyze the energy transfer efficiencies of rGO/PU and GO/PU, the evaporation rates were calculated by recording the mass change over time under solar illumination (1 and 10 kW m−2) within a thermal insulating layer. As shown in Figure 6e, the rGO/PU displays the highest evaporation rate, and it is 3.4 and 11.7 times higher than pure water and 1.2 and 1.3 times higher than the GO/PU at 1 and 10 kW m−2, respectively. The evaporation efficiency (ηv) was used to further analyze the performance of rGO/PU and GO/PU. The equation was defined as
ηv =
m•hlv Coptqi
where m• stands for the mass flux of the vaporized water, hlv denotes the total enthalpy of liquid−steam phase change, containing the sensible heat and the enthalpy of evaporation, and Coptqi is the total light energy to the sample provided by the light source. On the basis of the known weight change of the evaporated water, the evaporation efficiency and evaporation flux of rGO/ PU are determined under 1 and 10 kW m−2 solar irradiation (Figure 6e). At each light density, the efficiency and flux are compared with the efficiency and flux of water and GO/PU. As shows, the evaporation efficiency and evaporation flux of rGO/ PU outperforms the GO/PU, whether at low light intensity or high light intensity. Figure 6f shows that the rGO/PU can float on the water and form a water sheet on the top surface. A clear picture of steam generation can be observed at the surface of the rGO/PU under solar irradiation (Figure 6g). Efficiency of rGO/PU. Under a range of light density, we measured the evaporation rate enhanced by rGO/PU and the corresponding evaporation efficiency after 30 min illumination (Figure 7a). The evaporation rate almost increases linearly with the increase of optical concentrations and goes from 0.9 kg m−2 h−1 at 1 kW m−2 to 11.24 kg m−2 h−1 at 10 kW m−2. The evaporation efficiency of rGO/PU at solar illumination of 1 kW m−2 is 65%, whereas this efficiency at 10 kW m−2 achieves 81%. In general, the evaporation efficiency of rGO/PU is an increasing function of light density. In order to test the chemical stability of the functional foam, rGO/PU was soaked in a strong acidic (pH = 2) and strong
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ASSOCIATED CONTENT
S Supporting Information *
The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.chemmater.7b01280. Optimal ratio of polyols; effect of hydrophilic segment on solar steam generation; determination of optimum amount of GO; chemical stability test of rGO/PU; thermal conductivity measurement of wet PU and rGO/ PU (PDF) 5634
DOI: 10.1021/acs.chemmater.7b01280 Chem. Mater. 2017, 29, 5629−5635
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(17) Guo, A.; Fu, Y.; Wang, G.; Wang, X. Diameter effect of gold nanoparticles on photothermal conversion for solar steam generation. RSC Adv. 2017, 7, 4815−4824. (18) Liu, C.; Huang, J.; Hsiung, C.-E.; Tian, Y.; Wang, J.; Han, Y.; Fratalocchi, A. High-Performance Large-Scale Solar Steam Generation with Nanolayers of Reusable Biomimetic Nanoparticles. Advanced Sustainable Systems 2017, 1, 1600013. (19) Wang, X.; Ou, G.; Wang, N.; Wu, H. Graphene-based Recyclable Photo-Absorbers for High-Efficiency Seawater Desalination. ACS Appl. Mater. Interfaces 2016, 8, 9194−9199. (20) Lou, J.; Liu, Y.; Wang, Z.; Zhao, D.; Song, C.; Wu, J.; Dasgupta, N.; Zhang, W.; Zhang, D.; Tao, P.; Shang, W.; Deng, T. Bioinspired Multifunctional Paper-Based rGO Composites for Solar-Driven Clean Water Generation. ACS Appl. Mater. Interfaces 2016, 8, 14628−14636. (21) Sajadi, S. M.; Farokhnia, N.; Irajizad, P.; Hasnain, M.; Ghasemi, H. Flexible artificially-networked structure for ambient/high pressure solar steam generation. J. Mater. Chem. A 2016, 4, 4700−4705. (22) Ghasemi, H.; Ni, G.; Marconnet, A. M.; Loomis, J.; Yerci, S.; Miljkovic, N.; Chen, G. Solar steam generation by heat localization. Nat. Commun. 2014, 5, 4449. (23) Ishii, S.; Sugavaneshwar, R. P.; Nagao, T. Titanium Nitride Nanoparticles as Plasmonic Solar Heat Transducers. J. Phys. Chem. C 2016, 120, 2343−2348. (24) Ye, M.; Jia, J.; Wu, Z.; Qian, C.; Chen, R.; O’Brien, P. G.; Sun, W.; Dong, Y.; Ozin, G. A. Synthesis of Black TiOx Nanoparticles by Mg Reduction of TiO2 Nanocrystals and their Application for Solar Water Evaporation. Adv. Energy Mater. 2017, 7, 1601811. (25) Ito, Y.; Tanabe, Y.; Han, J.; Fujita, T.; Tanigaki, K.; Chen, M. Multifunctional Porous Graphene for High-Efficiency Steam Generation by Heat Localization. Adv. Mater. 2015, 27, 4302−4307. (26) Jiang, Q.; Tian, L.; Liu, K. K.; Tadepalli, S.; Raliya, R.; Biswas, P.; Naik, R. R.; Singamaneni, S. Bilayered Biofoam for Highly Efficient Solar Steam Generation. Adv. Mater. 2016, 28, 9400−9407. (27) Liu, Y.; Wang, X.; Wu, H. High-performance wastewater treatment based on reusable functional photo-absorbers. Chem. Eng. J. 2017, 309, 787−794. (28) Zhou, L.; Tan, Y.; Wang, J.; Xu, W.; Yuan, Y.; Cai, W.; Zhu, S.; Zhu, J. 3D self-assembly of aluminium nanoparticles for plasmonenhanced solar desalination. Nat. Photonics 2016, 10, 393−398. (29) Liu, Y.; Yu, S.; Feng, R.; Bernard, A.; Liu, Y.; Zhang, Y.; Duan, H.; Shang, W.; Tao, P.; Song, C.; Deng, T. A bioinspired, reusable, paper-based system for high-performance large-scale evaporation. Adv. Mater. 2015, 27, 2768−2774. (30) Ni, G.; Li, G.; Boriskina, S. V.; Li, H.; Yang, W.; Zhang, T.; Chen, G. Steam generation under one sun enabled by a floating structure with thermal concentration. Nature Energy 2016, 1, 16126. (31) Zhang, L.; Tang, B.; Wu, J.; Li, R.; Wang, P. Hydrophobic Lightto-Heat Conversion Membranes with Self-Healing Ability for Interfacial Solar Heating. Adv. Mater. 2015, 27, 4889−4894. (32) Wan, S.; Peng, J.; Jiang, L.; Cheng, Q. Bioinspired GrapheneBased Nanocomposites and Their Application in Flexible Energy Devices. Adv. Mater. 2016, 28, 7862−7898. (33) Stankovich, S.; Piner, R. D.; Nguyen, S. T.; Ruoff, R. S. Synthesis and exfoliation of isocyanate-treated graphene oxide nanoplatelets. Carbon 2006, 44, 3342−3347. (34) Mondal, T.; Bhowmick, A. K.; Krishnamoorti, R. Controlled Synthesis of Nitrogen-Doped Graphene from a Heteroatom Polymer and Its Mechanism of Formation. Chem. Mater. 2015, 27, 716−725. (35) Kim, H.; Miura, Y.; Macosko, C. W. Graphene/Polyurethane Nanocomposites for Improved Gas Barrier and Electrical Conductivity. Chem. Mater. 2010, 22, 3441−3450. (36) Wang, G.; Fu, Y.; Ma, X.; Pi, W.; Liu, D.; Wang, X. Reusable reduced graphene oxide based double-layer system modified by polyethylenimine for solar steam generation. Carbon 2017, 114, 117− 124. (37) Fu, Y.; Mei, T.; Wang, G.; Guo, A.; Dai, G.; Wang, S.; Wang, J.; Li, J.; Wang, X. Investigation on enhancing effects of Au nanoparticles on solar steam generation in graphene oxide nanofluids. Appl. Therm. Eng. 2017, 114, 961−968.
AUTHOR INFORMATION
Corresponding Author
*E-mail:
[email protected]. Fax: +862788661729. ORCID
Yang Fu: 0000-0002-1839-6053 Ankang Guo: 0000-0003-4826-7225 Jinhua Li: 0000-0002-5226-0272 Xianbao Wang: 0000-0001-7765-4027 Notes
The authors declare no competing financial interest.
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ACKNOWLEDGMENTS This work is financially supported by National Key R&D Program of China (Grant 2016YFA0200200) and National Natural Science Foundation of China (Grants 51272071, 51203045, and 21401049).
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REFERENCES
(1) Oki, T.; Kanae, S. Global hydrological cycles and world water resources. Science 2006, 313, 1068−1072. (2) Elimelech, M.; Phillip, W. A. The future of seawater desalination: energy, technology, and the environment. Science 2011, 333, 712−717. (3) Trieb, F.; Müller-Steinhagen, H. Concentrating solar power for seawater desalination in the Middle East and North Africa. Desalination 2008, 220, 165−183. (4) Sharon, H.; Reddy, K. S. A review of solar energy driven desalination technologies. Renewable Sustainable Energy Rev. 2015, 41, 1080−1118. (5) Armaroli, N.; Balzani, V. The future of energy supply: Challenges and opportunities. Angew. Chem., Int. Ed. 2007, 46, 52−66. (6) Lewis, N. S. Research opportunities to advance solar energy utilization. Science 2016, 351, aad1920. (7) Xiao, G.; Wang, X.; Ni, M.; Wang, F.; Zhu, W.; Luo, Z.; Cen, K. A review on solar stills for brine desalination. Appl. Energy 2013, 103, 642−652. (8) Gupta, M. K.; Kaushik, S. C. Exergy analysis and investigation for various feed water heaters of direct steam generation solar−thermal power plant. Renewable Energy 2010, 35, 1228−1235. (9) El-Agouz, S. A.; Abd El-Aziz, G. B.; Awad, A. M. Solar desalination system using spray evaporation. Energy 2014, 76, 276− 283. (10) Baffou, G.; Quidant, R. Thermo-plasmonics: using metallic nanostructures as nano-sources of heat. Laser & Photonics Reviews 2013, 7, 171−187. (11) de Aberasturi, D. J.; Serrano-Montes, A. B.; Liz-Marzán, L. M. Modern Applications of Plasmonic Nanoparticles: From Energy to Health. Adv. Opt. Mater. 2015, 3, 602−617. (12) Wang, J.; Li, Y.; Deng, L.; Wei, N.; Weng, Y.; Dong, S.; Qi, D.; Qiu, J.; Chen, X.; Wu, T. High-Performance Photothermal Conversion of Narrow-Bandgap Ti2O3 Nanoparticles. Adv. Mater. 2017, 29, 1603730. (13) Liu, Z.; Song, H.; Ji, D.; Li, C.; Cheney, A.; Liu, Y.; Zhang, N.; Zeng, X.; Chen, B.; Gao, J.; Li, Y.; Liu, X.; Aga, D.; Jiang, S.; Yu, Z.; Gan, Q. Extremely Cost-Effective and Efficient Solar Vapor Generation under Nonconcentrated Illumination Using Thermally Isolated Black Paper. Global Challenges 2017, 1, 1600003. (14) Li, X.; Xu, W.; Tang, M.; Zhou, L.; Zhu, B.; Zhu, S.; Zhu, J. Graphene oxide-based efficient and scalable solar desalination under one sun with a confined 2D water path. Proc. Natl. Acad. Sci. U. S. A. 2016, 113, 13953−13958. (15) Neumann, O.; Urban, A. S.; Day, J.; Lal, S.; Nordlander, P.; Halas, N. J. Solar vapor generation enabled by nanoparticles. ACS Nano 2013, 7, 42−49. (16) Jin, H.; Lin, G.; Bai, L.; Zeiny, A.; Wen, D. Steam generation in a nanoparticle-based solar receiver. Nano Energy 2016, 28, 397−406. 5635
DOI: 10.1021/acs.chemmater.7b01280 Chem. Mater. 2017, 29, 5629−5635
