Efficiency Desalination of

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Full-Spectrum Solar-to-Heat Conversion Membrane with Interfacial Plasmonic Heating Ability for High-Efficiency Desalination of Seawater Mengya Shang, Nian Li, Shudong Zhang, Tingting Zhao, Cheng Zhang, Cui Liu, Haifeng Li, and Zhenyang Wang ACS Appl. Energy Mater., Just Accepted Manuscript • DOI: 10.1021/acsaem.7b00135 • Publication Date (Web): 18 Dec 2017 Downloaded from http://pubs.acs.org on December 23, 2017

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ACS Applied Energy Materials

Full-Spectrum Solar-to-Heat Conversion Membrane with Interfacial Plasmonic Heating Ability for HighEfficiency Desalination of Seawater Mengya Shang, †,‡,§ Nian Li, †,§ Shudong Zhang,*, † Tingting Zhao, † Cheng Zhang, † Cui Liu, † Haifeng Li, †,‡ and Zhenyang Wang*,† †

Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui, 230031, China.

‡

Department of Chemistry, University of Science and Technology of China, Hefei, Anhui,

230026, China. KEYWORDS: solar-to-heat conversion, interfacial solar heating, porous membrane, hydrophilicity, self-floating

ABSTRACT: The current challenge in solar thermal utilization is how to effectively convert fullspectrum sunlight into directly available thermal energy for applications at high conversion efficiency. Herein, we report a novel strategy for the construction of large-area porous CuS/polyethylene (PE) hybrid membrane as a superior interfacial plasmonic photothermal material for high-efficiency solar thermal conversion to produce steam generation off seawater. The single-layer CuS/PE membrane materials have effective full spectra sunlight absorption, excellent solar-to-heat conversion ability, low thermal conductivity, good hydrophilicity and

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open micro-/nanoscopic porosity for capillarity and self-floating, etc.. Impressively, a single piece of porous CuS/PE membrane under one sun illumination can exhibit a superior conversion efficiency of 63.9% from sunlight to heat of seawater evaporation. Meanwhile, the plasmonic photothermal CuS/PE membrane can be recycled at least 20 times. Therefore, demonstrated convenient fabrication process, low cost and high evaporation efficiency, the single-layer porous CuS/PE membrane materials offer a great promise to convert sunlight into thermal energy for practical applications of steam generation.

The solar radiation is a promising and abundant source of clean, renewable and sustainable energy.1,2 Currently, effective utilization of solar energy for the production of other energy forms, such as chemical energy, electrical energy, and thermal energy, is one of the most significant strategies to develop green energy innovation for conquering the growing global energy crisis.3-6 Among above solar utilization technologies, solar heat is greatly available in the future energy supply and has the highest solar thermal energy conversion efficiency.7-9 Nowadays, solar radiation to heat water is the most common applicable form of solar energy in the world, including solar steam generation, desalination and distillation etc..10-16 However, how to effectively harvest and convert full-spectrum sunlight into directly available thermal energy at high conversion efficiency is still a barrier in its application of water evaporation. Meanwhile, it is extremely important to develop cost-effective solar heat conversion methods. Thus the design and synthesis of relevant materials for the full-spectrum absorption of solar radiation is crucial in both energy conversion field and desalination application. Considering water evaporation process occurring in thin air-water interface, recently, using nanostructured photothermal composites, including semiconductor materials, noble metal nanostructures, carbon fibers, and graphene etc.17-20 to convert sunlight into thermal energy is considered as a rational choice and a


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new strategy to effectively harvest solar illumination for water evaporation via heat localization. In principle, the materials for heat localization enable to enhancing local temperature of interfacial water for a high steam production rate. A key issue for solar energy conversion is the effective absorption of the whole solar spectrum to achieve high energy conversion efficiency. Another key issue is low thermal conductivity of composites for reducing the heat transfer from the surface of evaporative material to the bulk water. Thirdly, the materials for heat localization are expected to have open micro-/nano-scale porosity for both vapor channels and capillarity. Fourthly, it is necessary that the materials have hydrophilic surfaces to absorb enough water for steam generation. Last but not least, the lightweight characteristic is a prerequisite for selffloating capability of these composites at air-water interface, which can gain effective production by heat localization.

Magnetron Sputtering

Porous PE membrane

Porous Cu/PE membrane

Sulfuration

H22O O Vapour Vapor H

Interfacial Heating

Porous CuS/PE membrane

Solar Irradiation

Capillarity Water

Scheme 1. Schematic illustration for the preparation of the solar-to-heat conversion CuS/PE membrane for interfacial heating and the water evaporation process by employing the hydrophilic CuS/PE membrane.


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Herein, targeting at effectively enhancing only the local temperature of interfacial water for a high water evaporation rate, we develop a novel strategy for the construction of a piece of selffloating, large-area, hydrophilic, porous and black CuS/polyethylene (PE) plasmonic photothermal membrane with harvesting and converting full-spectrum sunlight capability for interfacial solar heating (Scheme 1). The membrane was prepared by firstly deposition of Cu onto the upper surface of the porous black polyethylene substrate, a common, cheap and polymeric material,21 followed by sulfuration to synthesize CuS nanoparticles for achieving desirable solar-to-heat conversion property. CuS nanocrystals were rational chosen as the photothermal material because of their plasmonic absorption in the near infrared radiation (NIR) region, high solar-thermal conversion efficiency, and easy fabrication among various semiconductor materials.22-25 Meanwhile, the black CuS/PE membrane has a rough porous surface, which can yield high absorption of incident light due to multiscattering.26,27 The numerous micro-scale pores within the CuS/PE membrane and improved hydrophilicity can potentially leverage capillary water flow to the heated areas, leading to rapid replenishment of surface water evaporated. Simultaneously, the thermal conductivity of the porous CuS/PE membrane is as low as 0.067 W m-1 K-1, obviously lower than pure water (0.556 W m-1 K-1), while the thermal conductivity of the PE is 0.448 W m-1 K-1.28 The low thermal conductivity allows CuS/PE membrane to behave as a good thermal insulator to prevent the heat transfer from the membrane to bulk water, which can help to reduce the heat loss due to the non-evaporative portion of the water due to thermal diffusion. Therefore, the porous CuS/PE membrane has many remarkable characteristics to meet all the necessary requirements for high-efficiency water evaporation by interfacial solar heating. Impressively, a single piece of porous CuS/PE membrane under one sun illumination can exhibit a superior conversion efficiency of 63.9%


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from sunlight to heat of water evaporation, which is higher than that of most of the current solar distilling units with typical efficiencies in the range of 30%-45%.29 Meanwhile, the plasmonic photothermal CuS/PE membrane can be recycled at least 20 times. This report represents a new method for the design and fabrication of better solar heating system and thus in the long run contributes to global efforts to solve the world's energy and water problems.

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Figure 1. (A) Optical picture of the CuS/PE membrane; (B) Optical microscope (OM) image of the CuS/PE membrane; (C) and (D) SEM images of the CuS/PE membrane; (E) UV-vis-NIR reflection/transmission/absorption spectra of CuS/PE membrane (Inset: UV-vis-NIR absorption spectra of CuS/PE, Cu/PE and PE membranes, respectively). (F) Time-courses of the


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temperature of CuS/PE (red line) , the Cu/PE membrane (blue line) and the PE (black line) membranes, under a halogen illumination; (G) and (H) Contact angles of water droplets on the PE and CuS/PE membrane, respectively.

Figure 1A shows that the black CuS/PE membrane can be fabricated in large area (15*15 cm), nearly a half of an A4 paper. There are open micro-scale porous channels in the CuS/PE membrane observed by optical microscope (Figure 1B), which can generate enough capillary forces that enable the replenishment of water as CuS/PE membrane’s surface water evaporates. Figure 1C shows the scanning electron microscope (SEM) image of the CuS/PE membrane which has a similar porous morphology to the PE membrane and Cu/PE membrane (Figure S1, Supporting Information). The average pore size of PE and Cu/PE membranes doesn’t change before and after sputtering Cu, which can be attributed to the low Cu content (1.46 wt %) which is not enough to change the comparatively large pore size of PE membrane. The CuS/PE membrane has a smooth edge differently to the rough-edge PE membrane and has an average pore size of ~73.9 µm and a thickness of ~112 µm (Figure S2, Supporting Information). The surface roughness of CuS/PE membrane adds extra evaporative surface area at the air-water interface and helps improve the evaporation rate. The structure of CuS/PE plays the important role of interfacial plasmonic heating for seawater desalination. Herein, the CuS NPs are mainly attached on the upper surface of the PE membrane, and there are little CuS NPs distributed in the micro-pores and back-side. Actually, the Cu was firstly coated on the surface of the porous PE matrix membrane through megnetron sputtering process. Due to the micro-pores existed in the PE matrix, a little of Cu was fell in the edges of the micro-pores and back-side. Subsequently the Cu was transferred to CuS NPs due to the sulfuration function of thiourea (Tu) molecules. Therefore, the finally formed plasmonic CuS nanoparticles are mainly attached on the upper


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surface of the CuS/PE membrane (Figure S3, Supporting Information), which have an average diameter of ~40 nm, as shown in Figure 1D. The new peaks appeared on the CuS/PE membrane’s XRD pattern demonstrate the successfully generation of CuS nanoparticles (Figure S4, Supporting Information) and the well-defined diffraction peaks within the 2θ range between 25° and 65° can be indexed as hexagonal phase (JCPDS Card NO.06-0464).30 The broader diffraction peaks show the formation of crystallites with smaller size and the strong and sharp diffraction peaks suggest that the obtained CuS nanoparticles are well crystalline in nature. HRTEM image shows that the lattice fringe is 0.278 nm, corresponding to the interplanar distance of (103) of hexagonal CuS (Figure S5, Supporting Information).31 As X-ray photoelectron spectroscopy (XPS) analysis shows (Figure S6, Supporting Information), the peaks taken for the Cu region are in agreement with Cu2+ and the peaks measured in the S energy region are typical values for metal sulfides and were assigned to S2-.32,33 Moreover, the CuS nanoparticles are tightly attached on the upper surface of PE substrate membrane, and there are no exfoliation of CuS nanoparticles even though folding the CuS/PE membrane several times (Figure S7, Supporting Information). This excellent foldability is convenient in transportation process, thus beneficial for effectively harvest solar illumination for water evaporation. Furthermore, the nanoparticles distributed structure on the upper surface of PE (Figure 1D) may have an effect on some characters of CuS/PE membrane, such as wettability, flexibility, etc..34 The black and rough surface of the CuS/PE membrane and plasmon absorption at or near infrared (NIR) range of CuS nanoparticles that has strong free carrier absorption by holes due to increased copper vacancies can increased the light absorption events and thus the absorption of the CuS/PE membrane,35 so the UV-vis-NIR absorption spectra of the CuS/PE, Cu/PE and PE membranes were measured to confirm the excellent light absorption property of CuS/PE


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membrane (Figure 1E). The reflection/transmission/absorption spectra show that the CuS/PE membrane has relatively high absorption (~93%), low transmittance (~2.5%) and reflection (~ 4%) , implying that most of solar light has been absorbed by CuS/PE membrane. On the other hand, the absorption spectra of Cu/PE and the PE membranes (Figure 1E Inset) are lower than that of the CuS/PE membrane due to the absence of the dark surface or CuS nanoparticles, which result in the less harvest of solar energy. Thus, the CuS/PE membrane with strong light absorption, higher than that of the AuNPs film and porous graphene sheets,13,19 can be utilized as an outstanding light-harvesting material for solar energy conversion. Next, the photothermal property of different membranes was evaluated under a halogen illumination (Experimental Details, Supporting Information). Figure 1F shows the surface temperature of the CuS/PE, Cu/PE and PE membranes, respectively. As can be seen, the surface temperature of the CuS/PE membrane increased quickly to its steady-state surface temperature of ~52 °C, with the ambient temperature being constant at ~26 °C. A steady-state temperature of the membrane could be reached, which indicates that an equilibrium temperature had been reached due to the balance between the heat generation under light irradiation and heat dissipation due to radiative heat flux. However, the Cu/PE membrane showed a steady-state surface temperature of ~42 °C while the PE membrane showed a steady-state surface temperature of ~33 °C which represented only ~7 °C increase under the halogen illumination. This result definitely demonstrates the efficient light-to-heat conversion property of the CuS/PE membrane. Moreover, the water evaporation rate (v) has a relationship with the temperature (T) as v=aT2, where a is a coefficient. And as Clapeyron-Clausius equation shows, lnP = -∆H/RT + C (where P is vapor press, ∆H is enthalpy, T is temperature, R and C are coefficients), higher temperature (T) lead to higher vapor press (P), and the evaporation rate (v) would be accelerated. Having shown an effective light-to-heat


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conversion performance, the CuS/PE membrane is obviously beneficial for practical applications such as desalination of seawater. Since the hydrophilicity and self-floating property of the CuS/PE membrane can help to absorb enough water for steam generation during localized interfacial heating, the highly hydrophilicity of the CuS/PE membrane was identified by contact angle measurement (Figure 1G and 1H). The PE and Cu/PE membranes show a strong hydrophobic behavior with large contact angles of 117.8° and 117.9° (Figure S8a, Supporting Information), respectively. For PE membrane, there is no exist of Cu, and the Tu and PVP molecules can’t react with PE membrane, thus the contact angle of PE membrane slightly changed when treated with different reagents (Figure S9, Supporting Information). However, the sulfuration process can significantly improve the wettability of Cu/PE membrane (Figure S8b-d, Supporting Information). The contact angle of the indicator water droplet changed to 9.6° within 0.96 s (Figure S10, Supporting Information), which shows the significant hydrophilicity of CuS/PE membrane. Herein, Polyvinylpyrrolidone (PVP) and thiourea (Tu) molecules may absorbed on the surface of CuS/PE membrane during the sulfuration process (absorbed PVP can be identified by N signal peak in XPS analysis in Figure S6d, Supporting Information), which mainly contributes to the improved hydrophilic property of CuS/PE membrane. All the results above demonstrate the excellent hydrophilicity of the CuS/PE membrane that is beneficial for the replenishment of water during interfacial solar heating.


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Figure 2. (A) The surface temperature of the water with CuS/PE membrane floating on the water surface (red line) and without membrane (black line) under solar irradiation (one sun); (B) The IR images of water beakers with CuS/PE membrane (b1) and without membrane (b2), without light (left) and under solar irradiation for 1 h (right). The bar is 2 cm; (C) Mass changes versus time (red line: with the CuS/PE membrane; black line: without membrane); (D) Evaporation cycle performance over 20 cycles, with each cycle sustained over 1 h using a beaker container.

Considering water evaporation process occurring at thin air-water interface, in principle, the materials for heat localization enable to enhancing local temperature of interfacial water for a high steam production rate. Although the Cu/PE membrane exhibited a good light absorption and a high steady-state surface temperature, the Cu/PE membrane was not proper for desalination of seawater without sulfuration due to the hydrophobic property of Cu/PE membrane with the contact angle of 117.97o (Figure S8a, Supporting Information). The water below couldn’t arrival to the surface and be heated. Additionally, the hydrophobicity of the Cu/PE membrane hindered the replenishment of water during interfacial solar heating. All these reasons lead to low steam production rate of Cu/PE membrane. On the other hand, the as-prepared CuS/PE membrane has


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many remarkable characteristics, including open micro-scale porosity for capillarity, effective full spectra sunlight absorption, high solar-to-heat conversion ability, good hydrophilicity, selffloating and low thermal conductivity, etc. to meet all the necessary requirements for highefficiency water evaporation by interfacial solar heating. Therefore, we measured the water evaporation performance with the CuS/PE membrane floating on the water surface under a simulated one-sun solar light with an intensity of 1000 W m−2 (Experimental Details, Supporting Information). As is shown in Figure 2A, after 1 h of simulated solar light irradiation, the surface temperature of the CuS/PE membrane that was floating on the water surface increased to its steady-state surface temperature of 37.6 °C which represented an obvious increase of ~11 °C, with the ambient temperature being constant at ~25.5 °C. Meanwhile, the water surface without a membrane showed a steady-state surface temperature of 31.6 °C which represented only an increase of ~6 °C under the solar irradiation. This result definitely demonstrates the efficient solar-to-heat conversion property of the CuS/PE membrane during the steam generation performance. IR images were captured and shown in Figure 2B. Due to the low thermal conductivity of CuS/PE membrane (0.067 W m-1 K-1), the thermal image of the beaker with the surface self-floating CuS/PE membrane (the right part of Figure 2b1) showed a sharper temperature gradient than the one without the membrane (Figure 2b2), where a uniform water temperature profile was obtained. These evidences prove that the heating without CuS/PE membrane results in the conventional bulk heating scheme and when there is a CuS/PE membrane floating on the water surface, the interfacial heating takes place. After 1 h of simulated solar light irradiation with the Cu/PE membrane floating at the surface of water, the mass loss of water with CuS/PE membrane and in absence of membrane was 1.28 g and 0.48 g (Figure 2C), respectively. The water evaporation rate was then calculated to be 1.021 kg m−2 h−1


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and 0.383 kg m−2 h−1, respectively. In order to differentiate the thermal performance of CuS/PE membrane, we utilize Formula (1) to calculate the solar energy to heat of water evaporation conversion efficiency (η). η = Qe/Qs

(1)

Where Qs is the incidence solar power (1000 W m−2), and Qe is the power of evaporation of the water, which can be calculated by Formula (2). Qe = He×(dm/dt) = He×v

(2)

Where He is the heat of evaporation of water (~2260 kJ kg−1), m is the mass of evaporated water, t is time, and v is the evaporation rate of water. The water evaporation conversion efficiency (η) of CuS/PE membrane was then estimated to be ~63.9%, which is much higher than the condition without the membrane, whose η was 23.9% then. This conversion efficiency of the CuS/PE membrane for solar energy to heat of water evaporation is also higher than that of most current solar stills, whose typical efficiencies are in a range of 30%-45%. Low thermal conductivity of CuS/PE membrane contributes to the high water evaporation conversion efficiency. The CuS/PE membrane has quite low thermal conductivity（0.067 W m-1 K-1), and when the CuS/PE membrane is floating on the bulk water, heat diffusion can be minimized and heat loss can be reduced from the evaporative surface to the non-evaporative portion of the water. Moreover, the CuS/PE membrane exhibits excellent stability. As shown in Figure 2D, the stable performance of CuS/PE membrane used in the water evaporation process over 20 cycles was demonstrated, with each cycle lasting 1 h using a beaker, and there was no obvious decrease in the solar energy to heat of water evaporation conversion efficiency of CuS/PE membrane under one sun irradiation. The results certify the successful strategy for interfacial water heating by using CuS/PE membrane.


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As is well-known, the power of light is in direct proportion to evaporation rate of water and the obtained CuS/PE membrane was illuminated under a high-power halogen lamp illumination to evaluate the interfacial plasmonic heating ability (Figure S11, Supporting Information). With the CuS/PE membrane floating on the water surface, the temperature of the surface increased to 64 °C while the temperature of water surface without a membrane increased to 59 °C. The minor difference in temperature was due to the high hydrophilicity of the CuS/PE membrane and the cold water beneath the membrane penetrated the pores of the CuS/PE membrane during the water evaporation process. The corresponding IR thermal images were shown in Figure S10c, when the illumination time is 0, 1 min and 14 min, respectively. The membranes can rise to a higher temperature in shorter time than those under solar irradiation, illustrating the significant photothermal conversion property of CuS/PE membrane. The mass changes were 1.18 g and 0.29 g, with and without CuS/PE membrane, respectively. For the CuS/PE membrane, the water evaporation appeared firstly and the final evaporation rate was 4.03 kg m−2 h-1, which represented 408% that of the case without the membrane (0.99 kg m−2 h-1). The self-floating CuS/PE membrane can potentially enhance the output of the water evaporation process, reduce the cost of extra thermal insulation installment, and further increase the usage of such clean water generation process. The full-spectrum interfacial plasmonic heating CuS/PE membrane with high water evaporation conversion efficiency is suitable for large-area production and has a great promise to directly produce freshwater. A simple and all-in-one solar distillation device was designed and fabricated based on the concept of solar-to-heat interfacial heating for simulated solar desalination process (Figure S12, Supporting Information). This device consists of light transparent plastic walls and a declining glass cover (Slope angle=10°).29 Inside the evaporation


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chamber, there is a solar-power electrical fan which is used to generate an air flow field. The collecting chamber is beneath the glass cover, which can collect the condensate water flowing down the cold glass cover when the device is illuminated by solar light and the water vapor is generated. The evaporation chamber is bottomed with the hydrophilic CuS/PE membrane (15*15 cm), which spontaneously floats on the surface of simulated sea water (Experimental Details, Supporting Information). The enhanced water collection property by the device with the CuS/PE membrane floating on the water surface is the result of excellent solar-to-heat conversion and reduced heat loss at the air-water interface. The result demonstrates the practical application of solar-to-heat CuS/PE membrane for point-of-use freshwater production. In conclusion, we have developed for the first time a common, low-cost and plasmonic CuS/PE membrane as an excellent interfacial solar heating material for highly effective desalination of seawater by effectively converting the sunlight to thermal energy. The obtained single-layer CuS/PE membrane only floating at seawater-air interface could generate a local high temperature to increase steam generation off seawater. A single piece of porous CuS/PE membrane under one sun illumination can exhibit a superior conversion efficiency of 63.9% from sunlight to heat of water evaporation. Meanwhile, the plasmonic photothermal CuS/PE membrane can be recycled at least 20 times, showing a good circulation property. Furthermore, we believe the plasmonic photothermal single-layer CuS/PE membrane will hold a great promise as a cost-effective material for next-generation solar heating system to harvest solar illumination into thermal energy for practical application of desalination of seawater. ASSOCIATED CONTENT


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Supporting Information. Structural information for the membranes, SEM, EDS, XRD, TEM, HRTEM, XPS and water contact angles, experimental details for the photothermal conversion under the halogen lamp and digital photograph of the point-of-use device. AUTHOR INFORMATION Corresponding Author * S.D. Zhang, E-mail: [email protected]; Z.Y. Wang, E-mail: [email protected]. Author Contributions The manuscript was written through contributions of all authors. All authors have given approval §

to the final version of the manuscript. Mengya Shang and Nian Li contributed equally.

Funding Sources This work was financially supported by the National Natural Science Foundation of China (No. U1432132, 61605222, 51202253 and 21703255), the Major/Innovative Program of Development Foundation of Hefei Center for Physical Science and Technology (2014FXZY001) and Natural Science Foundation of Anhui Province (Grant 1708085MB35). Notes The authors declare no competing financial interest. REFERENCES (1) Quoilin, S.; Orosz, M.; Hemond, H.; Lemort, V. Performance and Design Optimization of a Low-cost Solar Organic Rankine Cycle for Remote Power Generation. Solar Energy. 2011, 85, 955-966.


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(2) El-Agouz, S. A.; Abd El-Aziz, G. B.; Awad, A. M. Solar Desalination System Using Spray Evaporation. Energy 2014, 76, 276-283. (3) Zhuang, T.; Liu, Y.; Li, Y.; Zhao, Y.; Wu, L.; Jiang, J.; Yu, S. Integration of Semiconducting Sulfides for Full-Spectrum Solar Energy Absorption and Efficient Charge Separation. Angew. Chem. Int. Ed. 2016, 55, 6396-6400. (4) Han, S.; Gu, C.; Zhao, S.; Xu, S.; Gong, M.; Li, Z.; Yu, S. Precursor Triggering Synthesis of Self-coupled Sulfide Polymorphs with Enhanced Photoelectrochemical Properties. J. Am. Chem. Soc. 2016, 138, 12913-12919. (5) Zhao, G.; Sun, Y.; Zhou, W.; Wang, X.; Chang, K.; Liu, G.; Liu, H.; Kako, T.; Ye, J. Superior Photocatalytic H2 Production with Cocatalytic Co/Ni Species Anchored on Sulfide Semiconductor. Adv. Mater. 2017, 29, 1703258. (6) Zhang, R.; Wang, X.; Yu, S.; Wen, T.; Zhu, X.; Yang, F.; Sun, X.; Wang, X.; Hu, W. Ternary NiCo2Px Nanowires as pH-Universal Electrocatalysts for Highly Efficient Hydrogen Evolution Reaction. Adv. Mater. 2017, 29, 1605502. (7) Gao, X., Ren, H., Zhou, J., Du, R., Yin, C., Liu, R., Peng, H., Tong, L., Liu, Z., Zhang, J. Synthesis of Hierarchical Graphdiyne-Based Archithcture for Efficient Solar Steam Generation. Chem. Mater. 2017, 29, 5777-5781. (8) Walter, M. G.; Warren, E. L.; McKone, J. R.; Boettcher, S. W.; Mi, Q.; Santori, E. A.; Lewis, N. S. Solar Water Splitting Cells. Chem. Rev. 2010, 110, 6446-6473. (9) Brabec, C. J.; Sariciftci, N. S.; Hummelen, J. C. Plastic Solar Cells. Adv. Funct. Mater. 2001, 11, 15-26. (10) Finnerty, C., Zhang, L., Sedlak, D., Nelson, K., Mi, B. Synthetic Graphene Oxide Leaf for Solar Desalination with Zero Liquid Discharge. Environ. Sci. Technol. 2017, 51, 11701-11709.


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TOC Interfacial Plasmonic Heating

H2O Vapor Interfacial Heating

Capillarity Water

100 µm

Solar-to-heat Conversion Film


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Efficiency Desalination of

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