Robust and Low-Cost Flame-Treated Wood for High-Performance Solar Steam Generation

A Critical Perspective on Photothermal De-Icing

To tackle the formidable challenges posed by extreme cold weather events, significant advancements have been made in developing functional surfaces capable of efficiently removing accreted ice. Nevertheless, many of these surfaces still require external energy input, such as electrical power, which raises concerns regarding their alignment with global sustainability goals. Over the past decade, increasing attention has been directed toward photothermal surface designs that harness solar energy-a resource available on Earth in quantities exceeding the total reserves of coal and oil combined. By converting solar energy into heat, these designs enable the transformation of the interfacial solid-solid contact (ice-substrate) into a liquid-solid contact (water-substrate), significantly reducing interfacial adhesion and facilitating rapid ice removal. This critical perspective begins by emphasizing the advantages of photothermal design over traditional de-icing methods. It then delves into an in-depth analysis of three primary photothermal mechanisms, examining how these principles have expanded the scope of de-icing technologies and contributed to advancements in photothermal surface design. Finally, key fundamental and technical challenges are identified, offering strategic guidelines for future research aimed at enabling practical, real-world applications.

Interdisciplinary Hybrid Solar-Driven Evaporators: Theoretical Framework of Fundamental Mechanisms and Applications

The global water and energy crisis seems to be mitigated with promising prospects of emerging interdisciplinary hybrid solar-driven evaporator technology (IHSE). However, the lack of numeric standards for comparison between enormously reported systems and the synergistic effects of interdisciplinary hybridization remains a significant challenge. To entice researchers from various domains to collaborate on the design of a system for realistic, large-scale applications, this study provides a comprehensive overview of the interdisciplinary approaches to IHSE from the domains of physics, chemistry, materials science, and engineering, along with their guiding principles and underlying challenges. First, an in-depth analysis of IHSE with the basic scientific foundations and current advancements in recent years is discussed. Then, the physical principles/scientific principles alongside the overall system improvement enhancement techniques at the macro and micro scale are highlighted. Furthermore, the review analyzes the impact of significant physical factors that alter or restrict the efficiency of IHSE, as well as their connection and potential regulation. In addition, a comprehensive study of emerging sustainable applications for insight into the design and optimization of IHSE is provided for scientists from different fields. Lastly, the current challenges and future perspectives of interdisciplinary IHSE for large-scale applications are emphasized.

A facile and versatile preparation method of sodium alginate-copper sulfide photothermal coating for efficient solar evaporation

Utilizing inexhaustible solar energy for water purification represents a green and sustainable solution to water scarcity. However, the developments of efficient, inexpensive, convenient and reliable photothermal materials remain a major challenge. Herein, a facile and versatile preparation strategy of sodium alginate (SA)-CuS composite coating with superior adhesion and stability has been proposed toward high-efficiency solar-driven interfacial evaporation. The fabrication process can be quickly completed in aqueous solution with cheap reagents. The SA-CuS coating can be firmly adhered on different substrates, which can withstand rinsing treatment, iterative freeze-thaw cycles as well as high and low pH environments. The SA-CuS coating can convert various substrates into photothermal materials with broad light absorption for desirable solar evaporation because of high CuS loading and rough surface. As a proof of concept, a wood evaporator covered with the SA-CuS coating can achieve a water evaporation rate of ∼2.2 kg m-2 h- 1 under one sun illumination, which is superior to most reported wood-based solar evaporators.

Salvinia natans-Based Hierarchical Structures for Solar Thermal Clean Water Production from High-Salinity Wastewater

Biomaterial-based solar-driven evaporation has great potential for wastewater treatment and seawater desalination with a high energy conversion and utilization efficiency. However, technology gaps still exist for effectively and directly applying multiscale structures and intrinsic water transport channels of natural materials to enhance high-efficiency photothermal evaporation. In this study, a high-performance biomass-derived photothermal evaporative material was obtained using Salvinia natans, a common aquatic floating plant, together with simple poly(m-phenylenediamine) oxidation modification, building a hybrid biomass evaporator. With advantageous natural features of adequate water transport, microscale-nanoscale hierarchical structures, effective water activation, and antisalt-fouling function, the hybrid biomass evaporator achieves a high evaporation rate of 2.24 kg m-2 h-1 under one sun radiation (1 kW m-2). In addition, modified Salvinia natans also demonstrate certain ability to remove heavy metals during the photothermal evaporation of wastewater. This work offers a new perspective on the synthesis of an environmentally friendly and cost-effective solar-driven evaporator material, which has the advantages of low cost, simple process, and high photothermal conversion efficiency, and can be widely applied to seawater desalination and the treatment of wastewater with high salt concentrations.

Fabrication of Low-Cost Porous Carbon Polypropylene Composite Sheets with High Photothermal Conversion Performance for Solar Steam Generation

The development of absorber materials with strong light absorption properties and low-cost fabrication processes is highly significant for the application of photothermal conversion technology. In this work, a mixed powder consisting of NaCl, polypropylene (PP), and scale-like carbon flakes was ultrasonically pressed into sheets, and the NaCl was then removed by salt dissolution to obtain porous carbon polypropylene composite sheets (P-CPCS). This process is simple, green, and suitable for the low-cost, large-area fabrication of P-CPCS. P-CPCS has a well-distributed porous structure containing internal and external connected water paths. Under the dual effects of the carbon flakes and porous structure, P-CPCS shows excellent photothermal conversion performance in a broad wavelength range. P-CPCS-40 achieves a high temperature of 128 °C and a rapid heating rate of 12.4 °C/s under laser irradiation (808 nm wavelength, 1.2 W/cm2 power). When utilized for solar steam generation under 1 sun irradiation, P-CPCS-40 achieves 98.2% evaporation efficiency and a 1.81 kg m-2 h-1 evaporation rate. This performance means that P-CPCS-40 outperforms most other previously reported absorbers in terms of evaporation efficiency. The combination of carbon flakes, which provide a photothermal effect, and a porous polymer structure, which provides light-capturing properties, opens up a new strategy for desalination, sewage treatment, and other related fields.

High-Efficiency Photothermal Water Evaporation under Low-Intensity Sunlight Using Wood Biochar Monolith

Utilizing energy directly from the sun, solar water evaporation drives the global hydrological cycle and produces freshwater from saline water in the oceans and on land. As water is a poor solar absorber, a photothermal material is needed to facilitate the conversion of photons to thermal energy and increase the efficiency of solar desalination. However, the current photothermal materials are less efficient and expensive to be manufactured. Inspired by nature, we created a new photothermal material called a wood biochar monolith (WBM) by carbonizing wood using the pyrolysis process at 1000 °C and subsequently steaming at high pressure. Under low light intensity (193 W/m2), the light to vapor efficiency of maple WBM is more than 100%. The outstanding performance of WBM is attributed to (1) the facilitated water transport in the hierarchical, open-pore network preserved from the wood precursor in WBM and (2) the reduced evaporation enthalpy of confined water in WBM and the high broadband sunlight absorptivity of WBM. Moreover, the high evaporation rate causes the temperature of WBM to be lower than that of the surrounding water, enabling thermal energy harvesting by WBM from water and making a light-to-vapor efficiency of >100% feasible. This discovery offers opportunities for developing low-cost, high-performance water desalination or humidification devices deployable in remote areas with nonconcentrated natural sunlight.

A Sandwich Structure Ag/MgFe2O4-Deposited Surface Carbonized Wood for Integrated Solar Steam Generation and Photoreduction of Cr(VI)

The severe deterioration of the marine ecosystem significantly negatively impacts the performance of solar-driven steam generation (SSG) and the quality of the obtained freshwater. Herein, a bifunctional Ag/MgFe2O4@SCW reactor with a sandwich structure is designed for efficient SSG and Cr(VI) reduction, which is constructed via in situ deposit Ag nanoparticles (NPs) and MgFe2O4 onto surface carbonized wood (SCW). Owing to the advanced sandwich structure and strong interfacial interactions between each component, an ultra-high evaporation rate of 1.55 kg m-2 h-1 and the efficiency of 88.6% are achieved using Ag/MgFe2O4@SCW under 1 sun. The system exhibits the long-term evaporation performance in the simulated sewage and strong acid/base solutions along with water-harvesting capacity in outdoor solar desalination. The quality of distilled water after desalination of actual seawater and NaCl solutions with different concentrations meets the WHO-recommended drinkable water standards. Furthermore, Ag/MgFe2O4@SCW shows outstanding antibacterial property, self-desalting capacity, as well as reusability and structure stability. Most importantly, the fast carrier separation endows Ag/MgFe2O4@SCW with superior photocatalytic activity and Cr(VI) photoreduction of up to 96.1% after 180 min of illumination. The bifunctional Ag/MgFe2O4@SCW reactor provides an advanced synergistic mechanism for improving SSG and photocatalytic performance, while being promising for solar-powered production of clean water.

Recycling of waste coffee grounds as a photothermal material modified with ZnCl2 for water purification

The aim of this study was to develop a photothermal material modified with carbonization and ZnCl2 impregnation and supported by polyvinyl alcohol (PVA) for water purification using the waste coffee grounds. Scanning electron microscopy (SEM) characterization of the prepared material revealed that a significant surface modification was achieved due to the carbonization and ZnCl2 impregnation. X-ray diffraction analysis (XRD) pattern of the samples showed two broad peaks at 18.4° and 22.2°, this is due to the crystal planes of β-crystal phase structure, which indicates the existence of strong hydrogen bonds between the micro-structures and therefore less suspectable to chemical attack. Additionally, thermogravimetric analysis (TGA) result suggests a slight mass reduction between the temperature range of 65-75 °C implying the thermal stability of the prepared material. The produced modified material had a photothermal conversion efficiency of 74% and could produce vapor at a rate of 1.12 kg/m2h under 980 W/m2 irradiation at 1 sun. A significant reduction in Cu2+ ion concentration (83%), turbidity (91%), total dissolved solids (TDS) (61%), microbial load (95.6%), and total hardness (41.2%) were achieved. Therefore, waste coffee grounds can be considered as a future eco-friendly and low-cost candidate for water purification.

Solar interfacial evaporation devices for desalination and water treatment: Perspective and future

Water is an essential commodity for society, and alternate resources such as seawater and wastewater are vital for the future. There are various desalination technologies that can provide sufficient and sustainable water sources. Renewable energy-based desalination technologies like solar-based interfacial evaporation are very efficient and sustainable desalination methods. Solar-based interfacial evaporation has been a focus due to its efficient and easy-to-use methods. Still, research is needed for fouling resistance, scalable and low-cost materials, and devices for solar interfacial evaporation. Recent research focuses on the materials for evaporation devices, but various other aspects of device design and fabrication methods are also necessary to improve device performance. In this article, all the evaporator device configurations and strategies for efficient evaporator devices are compiled and summarized. The evaporator devices have been classified into eight main categories: monolayer, bilayer, tree-like design, low-temperature designs, 3D-Origami-based designs, latent heat recovery design, design with storage/batch process, and contactless design. It was found that a good absorber, well-engineered air-water interface, and bottom-layer insulation are necessary for the best systems. The current research focuses on the vapor production output of the devices but not on the water production from devices. So, the focus on device-based water production and the associated cost of the water produced is essential. This article articulates the strategies and various scalable and efficient devices for evaporation-based solar-driven desalination. This article will be helpful for the researchers in improving devices output and coming up with a sustainable desalination and water treatment.

Interfacial Solar Evaporation: From Fundamental Research to Applications

In the last decade, interfacial solar steam generation (ISSG), powered by natural sunlight garnered significant attention due to its great potential for low-cost and environmentally friendly clean water production in alignment with the global decarbonization efforts. This review aims to share the knowledge and engage with a broader readership about the current progress of ISSG technology and the facing challenges to promote further advancements toward practical applications. The first part of this review assesses the current strategies for enhancing the energy efficiency of ISSG systems, including optimizing light absorption, reducing energy losses, harvesting additional energy, and lowering evaporation enthalpy. Subsequently, the current challenges faced by ISSG technologies, notably salt accumulation and bio-fouling issues in practical applications, are elucidated and contemporary methods are discussed to overcome these challenges. In the end, potential applications of ISSG, ranging from initial seawater desalination and industrial wastewater purification to power generation, sterilization, soil remediation, and innovative concept of solar sea farm, are introduced, highlighting the promising potential of ISSG technology in contributing to sustainable and environmentally conscious practices. Based on the review and in-depth understanding of these aspects, the future research focuses are proposed to address potential issues in both fundamental research and practical applications.

Research Advances in Wood Composites in Applications of Industrial Wastewater Purification and Solar-Driven Seawater Desalination

In recent years, the ecosystem has been seriously affected by sewage discharge and oil spill accidents. A series of issues (such as the continuous pollution of the ecological environment and the imminent exhaustion of freshwater resources) are becoming more and more unmanageable, resulting in a crisis of water quality and quantity. Therefore, studies on industrial wastewater purification and solar-driven seawater desalination based on wood composites have been widely considered as an important development direction. This paper comprehensively analyzes and summarizes the applications of wood composites in the fields of solar-driven seawater desalination and polluted water purification. In particular, the present situation of industrial wastewater containing heavy metal ions, microorganisms, aromatic dyes and oil stains and related problems of solar-driven seawater desalination are comprehensively analyzed and summarized. Generally, functional nanomaterials are loaded into the wood cell wall, from which lignin and hemicellulose are selectively removed. Alternatively, functional groups are modified on the basis of the molecular structure of the wood microchannels. Due to its three-dimensional (3D) pore structure and low thermal conductivity, wood is an ideal substrate material for industrial wastewater purification and solar-driven seawater desalination. Based on the study of objective conditions such as the preparation process, modification method and selection of photothermal conversion materials, the performances of the wood composites in filtration, adsorption and seawater desalination are analyzed in detail. In addition, this work points out the problems and possible solutions in applying wood composites to industrial wastewater purification and solar-driven seawater desalination.

Redesigning Natural Materials for Energy, Water, Environment, and Devices

The United Nations Framework Convention on Climate Change (UNFCCC) acknowledges that global cooperation is paramount to mitigate climate change and further warming. The global community is committed to renewable energy and natural materials to tackle this challenge for all humankind. The widespread use of natural materials is embraced as one such action to reach net-zero carbon emissions. Given the hierarchical framework and earth abundance, cellulose-based materials extend their negative carbon benefits to our daily products and accelerate our pace toward carbon neutrality. Here, we present an overview of recent developments of cellulose-based materials in upsurging applications in radiative cooling, thermal insulation, nanofluidics, and wearable devices. We also highlight various modifications and functionalized processes that transform massive amounts of cellulose into green products. The prosperous development of functionalized cellulose materials aligns with a circular economy. Expedited interdisciplinary fundamental investigations are expected to make fibrillated cellulose penetrate more into carbon downdraw at speed and scale.

Phonon-Engineered Hard-Carbon Nanoflorets Achieving Rapid and Efficient Solar-Thermal Based Water Evaporation and Space-Heating

Generation and utilization of green heat produced from solar energy demand broadband absorbers with the elusive combination of strong phonon-driven photon thermalization and, contrastingly, weak phonon-lattice thermal conductivity. Here, we report a new class of porous, nanostructured hard-carbon florets (NCFs) consisting of isotropically assembled conical microcavities for greater light entrapment and efficient broad-band absorption (95% over 250-2500 nm). Resembling marigolds, the NCF exhibits short-range graphitic order that promotes instantaneous and efficient solar-thermal conversion (ηSTC = 87%) while exhibiting long-range intrinsic disorder providing low thermal conductivity (1.5 W m-1 K-1) to minimize thermal loss (13%). Solution processable NCF coatings on arbitrarily substrates (filter paper, terracotta, Cu and Al tubes) generate surface temperature of 400 ± 2 K and exhibit high thermal effusance (519 W s0.5 m-2 K-1) to achieve highest combination of (a) rate of solar-driven interfacial water evaporation (Rw = 5.4 kg m-2 h-1, 2 sun), (b) solar-vapor conversion efficiency (ηSVC = 186%), and (c) ηSTC (87%) among known materials. Such robust performance is retained for beyond 30 days of continuous operation and under different solar power (1 sun to 5 sun). Furthermore, active space heating (outlet air temperature = 346 ± 3 K) using NCF coatings is demonstrated.

A high-efficient and salt-rejecting 2D film for photothermal evaporation

The solar-driven desalination is seen as a sustainable way to combat water scarcity. However, the solar steam generation efficiency has long been restricted by the high vaporization enthalpy of water and low energy density of natural sunlight. We introduced graphene oxide (GO) cross-linked with polyethyleneimine (PEI) as the photothermal material, with the enriched ammonic functional groups in modified GO membrane (GPM) activating water molecules to evaporate with much lower energy consumption. The vaporization enthalpy at the air-film interface is reduced up to 42% in GPM film by tuning the thermodynamic states of water. Consequently, GPM film enables a high evaporation rate of 2.48 kg m-2 h-1 with 95.7% energy conversion efficiency under 1 sun. With the aid of positive charges introduced by hydrolysis of PEI, the GPM exhibits excellent salt resistance and delivers an evaporation rate around 1.8 kg m-2 h-1 when treating 20 wt % NaCl solution.

Lamellar Wood Sponge with Vertically Aligned Channels for Highly Efficient and Salt-Resistant Solar Desalination

Solar-assisted interfacial evaporation is a promising approach for purifying and desalinating water. As a sustainable biomass material, wood has attracted increasing interest as an innovative substrate for solar desalination, owing to its intrinsic porous structure, high hydrophilicity, and low thermal conductivity. However, developing wood-based solar evaporators with high evaporation rates and excellent salt resistance still remains a significant challenge, owing to the absence of large pores with high interconnectivity in natural wood. Herein, by converting the honeycombed structure of natural wood into a lamellar architecture via structural engineering, we develop a flexible wood sponge with vertically aligned channels for efficient and salt-resistant solar desalination after surface coating with carbon nanotubes (CNTs). The special lamellar structure with an interlayer distance of 50-300 μm provides the wood sponge with faster water transport, lower thermal conductivity, and water evaporation enthalpy, thus achieving higher evaporation performances in comparison with the cellular structure of natural wood. Noteworthy, the vertically aligned channels of the wood sponge facilitate sufficient fluid convection and diffusion and enable efficient salt exchanges between the heating interface and the underlying bulk water, thus preventing salt accumulation on the surface. Benefiting from the distinctive lamellar structure, the developed wood-sponge evaporator exhibits exceptional salt resistance even in a hypersaline brine (20 wt %) during continuous 7-day desalination under 1 sun irradiation, with a high evaporation rate (1.38-1.43 kg m-2 h-1), outperforming most previously reported wood-based evaporators. The lamellar wood sponge may provide a promising strategy for desalinating high-salinity brines in an efficient manner.

Accelerating the solar-thermal energy storage via inner-light supplying with optical waveguide

Solar-thermal storage with phase-change material (PCM) plays an important role in solar energy utilization. However, most PCMs own low thermal conductivity which restricts the thermal charging rate in bulk samples and leads to low solar-thermal conversion efficiency. Here, we propose to regulate the solar-thermal conversion interface in spatial dimension by transmitting the sunlight into the paraffin-graphene composite with side-glowing optical waveguide fiber. This inner-light-supply mode avoids the overheating surface of the PCM, accelerates the charging rate by 123% than that of the traditional surface irradiation mode and increases the solar thermal efficiency to ~94.85%. Additionally, the large-scale device with inner-light-supply mode works efficiently outdoors, indicating the potential of this heat localization strategy in practical application.

Photothermal Nanomaterials: A Powerful Light-to-Heat Converter

All forms of energy follow the law of conservation of energy, by which they can be neither created nor destroyed. Light-to-heat conversion as a traditional yet constantly evolving means of converting light into thermal energy has been of enduring appeal to researchers and the public. With the continuous development of advanced nanotechnologies, a variety of photothermal nanomaterials have been endowed with excellent light harvesting and photothermal conversion capabilities for exploring fascinating and prospective applications. Herein we review the latest progresses on photothermal nanomaterials, with a focus on their underlying mechanisms as powerful light-to-heat converters. We present an extensive catalogue of nanostructured photothermal materials, including metallic/semiconductor structures, carbon materials, organic polymers, and two-dimensional materials. The proper material selection and rational structural design for improving the photothermal performance are then discussed. We also provide a representative overview of the latest techniques for probing photothermally generated heat at the nanoscale. We finally review the recent significant developments of photothermal applications and give a brief outlook on the current challenges and future directions of photothermal nanomaterials.

Omnidirectionally irradiated three-dimensional molybdenum disulfide decorated hydrothermal pinecone evaporator for solar-thermal evaporation and photocatalytic degradation of wastewaters

Although most solar steam generation devices are effective in desalinating seawater and purifying wastewaters with heavy metal ions, they are ineffective in degrading organic pollutants from wastewaters. Herein, we design novel solar-driven water purification devices by decoration of three-dimensional pinecones with MoS₂ nanoflowers via a one-step hydrothermal synthesis for generating clean water. The vertically arrayed channels in the central rachis and the unique helically arranged scales of the hydrothermal pinecone can not only transfer bulk water upward to the evaporation surface, but also absorb more solar light from different incident angles for solar-thermal evaporation and photodegradation of wastewaters under omnidirectional irradiations. The decorated MoS₂ nanoflowers can not only enhance the solar-thermal energy conversion efficiency, but also decompose organic pollutants in the bulk water by their photocatalytic degradation effects. The resultant hydrothermal pinecone with in situ decorated MoS₂ (HPM) evaporator exhibits a high evaporation rate of 1.85 kg m^-2 h^-1 under 1-sun irradiation with a high energy efficiency of 96 %. During the solar-driven water purification processes, the powdery HPM can also photodegrade organic pollutants of methylene blue and rhodamine B with high removal efficiencies of 96 % and 95 %, respectively. For practical demonstration, by floating in the methylene blue solution under 1-sun irradiation, the bulky HPM can generate clean water by simultaneous solar-thermal evaporation and photocatalytic degradation. The integration of solar steam generation and photocatalytic degradation mechanisms makes the HPM evaporator highly promising for practical high-yield purification of wastewaters.

3D Janus structure MXene/cellulose nanofibers/luffa aerogels with superb mechanical strength and high-efficiency desalination for solar-driven interfacial evaporation

Interfacial solar steam generation (ISSG) is considered to be an attractive technique to address the water shortage. However, developing a sustainable thermal management, salt rejection, and excellent mechanical strength ISSG device for long-term stability desalination is still a challenge. Herein, a biomass ISSG device with superb mechanical properties was prepared by introducing a luffa sponge as the skeleton and constructing the MXene/cellulose nanofibers (CNFs) aerogels via freeze-drying. The Janus MXene-decorated CNFs/luffa (JMCL) aerogels integrated the multifunction of fast water transport, good thermal management, and efficient photothermal conversion in a single module, to achieve high-efficiency desalination. 3D Janus structure endowed the JMCL aerogel with opposite wettability, which is feasible to construct the localized photothermal generation and self-floating. The mechanical strength of JMCL aerogels is 437 times that of MXene/CNFs aerogels. The JMCL aerogels delivered a water evaporation rate of 1.40 kg m^-2h^-1 and an efficiency of 91.20% under 1 sun illumination. The excellent salt resistance during 24 h working and long-term solar vapor generation of up to 28 days were achieved. The multifunctional JMCL aerogels with 3D Janus structure offer new insights for developing good durability and eco-friendly biopolymer-based steam generators.

Modulating photothermal properties by integration of fined Fe-Co in confined carbon layer of SiO2 nanosphere for pollutant degradation and solar water evaporation

Environmental governance by photothermal materials especially for the separation of organic pollutants and regeneration of freshwater afford growing attention owing to their special solar-to-heat properties. Here, we construct a special functional nanosphere composed of an internal silica core coated by a thin carbon layer encapsulated plasmonic bimetallic FeCo₂O₄ spinel (SiO₂@CoFe/C) by a facile self-assembled approach and tuned calcination. Through combining the advantage of bimetallic Fe-Co and carbon layer, this obtained nanosphere affords improved multiple environmental governing functions including peroxymonosulfate (PMS) activation to degrade pollutants and photothermal interfacial solar water evaporation. Impressively, fined bimetal (FeCo) species (20 nm) acted as main catalytic substance were distributed on the N-doping carbon thin layer, which favors electron transfer and reactive accessibility of active metals. The increasing treatment temperature of catalysts caused the optimization of the surface active metal species and tuning catalytic properties in the AOPs. Besides, the incorporation of Co in the SiO₂@CoFe/C-700 could enable the improved PMS activation efficiency compared to SiO₂@Fe/C-700 and the mixed SiO₂@Co/C-700 and SiO₂@Fe/C-700, hinting a synergetic promotion effect. The bimetal coupled catalyst SiO₂@CoFe/C-700 affords enhanced photothermal properties compared to SiO₂@Co/C-700. Furthermore, photothermal catalytic PMS activation using optimal SiO₂@CoFe/C-700 was further explored in addressing stubborn pollutants including oxytetracycline, sulfamethoxazole, 2, 4-dichlorophenol, and phenol. The free radical quenching control suggests that both the sulfate radical, hydroxyl radical, superoxide radical, and singlet oxygen species are involved in the degradation, while the hydroxyl radical and singlet oxygen play a dominant role. Furthermore, the implementation of a solar-driven interfacial water evaporation model using SiO₂@CoFe/C-700 was further studied to obtain freshwater regeneration (1.26 kg m^-2 h^-1, 76.81% efficiency), indicating the comprehensive ability of the constructed nanocomposites for treating complicated environmental pollution including organics removal and freshwater regeneration.

Dual-Functional Solar-to-Steam Generation and SERS Detection Substrate Based on Plasmonic Nanostructure

Solar-to-steam (STS) generation based on plasmonic materials has attracted significant attention as a green method for producing fresh water. Herein, a simple in situ method is introduced to fabricate Au nanoparticles (AuNPs) on cellulose filter papers as dual-functional substrates for STS generation and surface-enhanced Raman spectroscopy (SERS) sensing. The substrates exhibit 90% of broadband solar absorption between 350 and 1800 nm and achieve an evaporation rate of 0.96 kg·m^-2·h^-1 under 1-sun illumination, room temperature of 20 °C, and relative humidity of 40%. The STS generation of the substrate is stable during 30 h continuous operation. Enriched SERS hotspots between AuNPs endow the substrates with the ability to detect chemical contamination in water with ppb limits of detection for rhodamine 6G dye and melamine. To demonstrate dual-functional properties, the contaminated water was analyzed with SERS and purified by STS. The purified water was then analyzed with SERS to confirm its purity. The developed substrate can be an improved and suitable candidate for fresh water production and qualification.

Wooden Solar Evaporator Design Based on the Water Transpiration Principle of Trees

The double-sided carbonization of poplar with different sections forms a three-layer structure inspired by tree water transpiration. A photothermal evaporation comparison experiment was conducted to simulate the influence of solar radiation intensity (1 kW·m^-2) on uncarbonized and single- and double-sided carbonized poplar specimens. The tissue structure, chemical functional group changes, and profile density of the specimens were analyzed using scanning electron microscopy, Fourier transform infrared spectrometry, and X-ray profile density testing, respectively. The results showed that the tissue structure of the specimen changed after treatment, and the relationship of water evaporation was shown as follows: cross-section (C) > Radial section (R) > Tangential section (T), and Double-sided carbonized poplar (DCP) > Single-sided carbonized poplar (SCP) > Non-carbonized poplar (NCP). Of these, the maximum photothermal evaporation was from the cross-section of the double-sided carbonized poplar (NCPC) with a value of 1.32 kg·m^-2·h^-1, which was 21.97% higher than single-sided carbonized poplar (SCPC) and 37.88% higher than non-carbonized poplar (NCPC). Based on the results, double-sided carbonization three-layer structure treatment can improve the evaporation force of the poplar interface, thereby improving the moisture migration ability of wood, and can be applied to solar interface absorber materials.

Robust, Scalable, and Cost-Effective Surface Carbonized Pulp Foam for Highly Efficient Solar Steam Generation

Recently, a solar-driven evaporator has been applied in seawater desalination, but the low stability, high cost, and complex fabrication limit its further application. Herein, we report a novel, low-cost, scalable, and easily fabricated pulp-natural rubber (PNR) foam with a unique porous structure, which was directly used as a solar-driven evaporator after facile surface carbonization. This surface carbonized PNR (CPNR) foam without interface adhesion or modification was composed of a top photothermal layer with light absorption ability and a bottom hydrophilic foam layer with a porous and interconnected network structure. Due to the strong light absorption ability (93.2%) of the carbonized top layer, together with the low thermal conductivity (0.1 W m K^-1) and good water adsorption performance (9.9 g g^-1) of the bottom layer, the evaporation rate and evaporation efficiency of the pulp foam evaporator under 1 sun of illumination attained 1.62 kg m^-2 h^-1 and 98.09%, respectively, which were much higher than those of most cellulose-based solar-driven evaporators. Furthermore, the CPNR foam evaporator with high cost-effectiveness presented high light-thermal conversion, heat localization, and good salt rejection properties due to the unique porous structure. Additionally, the CPNR foam evaporator exhibited potential applications in the treatments of simulated sewage, metal ion concentration, and seawater desalination. Its cost-effectiveness was clearly higher than that of most reported evaporators as well. Therefore, this novel, low-cost, and stable pulp foam evaporator demonstrated here can be a very promising solution for water desalination and purification.

Waste sawdust-based composite as an interfacial evaporator for efficient solar steam generation

Interfacial evaporation is the technology of localizing heat energy at the air-water interface and is used for getting potable water from salty or seawater effectively. In this work, we introduce a novel interfacial evaporator by blending different weight ratios of waste sawdust (1 g, 2 g, 3 g and 4 g) with bisphenol-A epoxy resin (LY556) and triethyltetramine hardener (HY951). The fabricated epoxy hardener sawdust (EHS) composite material was subjected to various characterizations for the possibility of using it in solar steam generation. Consequently, EHS displayed high light absorption, amorphous structure, functional groups, and large number of pores. The main objective of the study was to investigate interfacial solar steam generation with and without interfacial evaporators (EHS-1g, EHS-2g, EHS-3g, and EHS-4g) under indoor conditions. The maximum mass loss of water, evaporation rate and evaporation efficiency were found to be 4.5 g, 1.398 kg m-2 h-1, and 92.99%, respectively, for the EHS-4g evaporator. The salinity of the distilled condensed water was measured and was below the WHO standards. The results are due to (i) the large number of cross-linked porous structures used to permeate water at the evaporative surface by capillary action, (ii) low thermal conductivity of the composite that offers an efficient broad and strong light absorption, and (iii) existence of a larger hydraulic diameter and small tortuosity of pores, which reduces the salt ion penetration distance and dispatch back to bulk water.

3D carbonized grooved straw with efficient evaporation and salt resistance for solar steam generation

Solar steam generation (SSG) is considered an effective solution to the global shortage of freshwater resources. To solve the practical application challenges of SSG in remote outdoor environments where electricity is scarce, it is of great importance to developing new solar evaporators. In this study, a three-dimensional (3D) biochar solar evaporator based on carbonized grooved straw was prepared from agricultural waste corn straw, which had high solar energy conversion efficiency and excellent salt resistance. The existence of grooves increases the surface area to absorb more sunlight and makes the light multilevel reflection improve the evaporation rate. The excellent light absorption, super hydrophilic, and heat shielding properties of 3D carbonized grooved straw resulted in a good evaporation rate (1.57 kg⋅m^-2·h^-1) and energy efficiency (85.9%) under 1 sun irradiation. The 3D grooved biochar solar distiller also demonstrated efficient formation evaporation performance and excellent salt resistance in practical applications in seawater desalination and surface water purification. The 3D grooved biochar solar distiller prepared from agricultural waste has the advantages of being economical and environmentally friendly, with good application prospects.

Biomass-based materials for solar-powered seawater evaporation

Clean and safe water is crucial to maintaining human life on earth. Solar-powered seawater desalination (SSD) is a promising and feasible way to use solar energy resources to overcome water scarcity. Among all the candidate materials for solar seawater evaporators, biomass-based materials stand out thanks to their excellent inherent natural structure, ease of preparation, low cost, and abundant resources. In this article, we review biomass-based materials, from angiosperms, algae, and fungi to animal materials and other atypical biomass materials, proposed for solar-powered seawater evaporation in the shape of the nanofluid, membrane, gels, composite sponge structures, composites Janus structures and other composites. The approaches for improving biomass-based solar seawater evaporators (BSSE) performance are emphasized, including optical absorption regulation, system thermal management optimization, adequate water supply, salt resistance, and effective steam condensate recovery. In the end, the opportunities and challenges of biomass-based materials for SSD are illustrated.

Inhibition of Phenol from Entering into Condensed Freshwater by Activated Persulfate during Solar-Driven Seawater Desalination

Recently, solar-driven seawater desalination has received extensive attention since it can obtain considerable freshwater by accelerating water evaporation at the air-water interface through solar evaporators. However, the high air-water interface temperature can cause volatile organic compounds (VOCs) to enter condensed freshwater and result in water quality safety risk. In this work, an antioxidative solar evaporator, which was composed of MoS₂ as the photothermal material, expandable polyethylene (EPE) foam as the insulation material, polytetrafluoroethylene (PTFE) plate as the corrosion resistant material, and fiberglass membrane (FB) as the seawater delivery material, was fabricated for the first time. The activated persulfate (PS) methods, including peroxymonosulfate (PMS) and peroxodisulfate (PDS), were applied to inhibit phenol from entering condensed freshwater during desalination. The distillation concentration ratio of phenol (R_D) was reduced from 76.5% to 0% with the addition of sufficient PMS or PDS, which means that there was no phenol in condensed freshwater. It was found that the Cl^- is the main factor in activating PMS, while for PDS, light, and heat are the dominant. Compared with PDS, PMS can make full utilization of the light, heat, Cl^- at the evaporator's surface, resulting in more effective inhibition of the phenol from entering condensed freshwater. Finally, though phenol was efficiently removed by the addition of PMS or PDS, the problem of the formation of the halogenated distillation by-products in condensed freshwater should be given more attention in the future.

Reviewing wood-based solar-driven interfacial evaporators for desalination

Solar‒driven interfacial water evaporation is a convenient and efficient strategy for harvesting solar energy and desalinating seawater. However, the design and fabrication of solar evaporators still challenge reliable evaporation and practical applications. Wood-based solar-driven interfacial water evaporation emerge as a promising and environmentally friendly approach for water desalinating as it provides renewable and porous structures. In recent years, surface modifications and innovative structural designs to prepare high performance wood-based evaporators is widely explored. In this review, we firstly describe the superiority of wood for the fabrication of wood-based solar evaporators, including the pore structure, chemical structure and thermal insulation. Secondly, we summarize the recent developments in wood-based evaporators from surface carbonization, decoration with photothermal materials, bulk modification and structural design, and discuss from the aspects of water transportation capacity, thermal conductivity and photothermal efficiency. Finally, based on these previous results and analysis, we highlight the remaining challenges and potential future directions, including the selection of high-efficient photothermal materials, heat and mass transfer mechanism in wood-based evaporators including large-scale production at a low cost.

Reclaimable MoS2 Sponge Absorbent for Drinking Water Purification Driven by Solar Energy

With the fast development of modern industries, scarcity of freshwater resources caused by heavy metal pollution (i.e., Hg²⁺) has become a severe issue for human beings. Herein, a 3D-MoS₂ sponge as an excellent absorbent is fabricated for mercury removal due to its multidimensional adsorption pathways, which decreases the biomagnification effect of methylmercury in water bodies. Furthermore, a secondary water purification strategy is employed to harvest drinkable water with the exhausted adsorbents, thus alleviating the crisis of drinking water shortage. Compared to the conventional landfill treatment, the exhausted MoS₂ sponge absorbents are further functionalized with a poly(ethylene glycol) (PEG) layer to prevent the heavy metals from leaking and enhance the hydrophilicity for photothermal conversion. The fabricated evaporator displays excellent evaporation rates of ∼1.45 kg m^-2 h^-1 under sunlight irradiation and produces freshwater with Hg²⁺ under the WHO drinking water standard at 0.001 mg L^-1. These results not only assist in avoiding the biodeposition effect of mercury in water but also provide an environment-friendly strategy to recycle hazardous adsorbents for water purification.

Marangoni Effect Drives Salt Crystallization Away from the Distillation Zone for Large-Scale Continuous Solar Passive Desalination

Solar desalination shows great potential in dealing with global water scarcity. A multistage passive solar distiller with thermal localization is especially attractive for its high-water yield. However, achieving long-term stability in large-scale devices remains a challenge because of the easy accumulation of crystallized salt inside the distiller. Here, we reported that the Marangoni effect can drive crystallized salt away along a long distance in a capillary wick, which endow the multistage passive solar distiller with the ability of salt-rejecting. In a 36 h continuous testing, the salinity of the distillation zone is limited below 12 wt % and crystallized salt only accumulates outside the device. The water yield is about 1.7 kg m^-2 h^-1 in a three-stage device, with a solar-to-vapor conversion efficiency of 114% under one sun. This novel design proves a new principle for high efficiency and long-term stable solar desalination.

Efficient Preconstruction of Three-Dimensional Graphene Networks for Thermally Conductive Polymer Composites

Electronic devices generate heat during operation and require efficient thermal management to extend the lifetime and prevent performance degradation. Featured by its exceptional thermal conductivity, graphene is an ideal functional filler for fabricating thermally conductive polymer composites to provide efficient thermal management. Extensive studies have been focusing on constructing graphene networks in polymer composites to achieve high thermal conductivities. Compared with conventional composite fabrications by directly mixing graphene with polymers, preconstruction of three-dimensional graphene networks followed by backfilling polymers represents a promising way to produce composites with higher performances, enabling high manufacturing flexibility and controllability. In this review, we first summarize the factors that affect thermal conductivity of graphene composites and strategies for fabricating highly thermally conductive graphene/polymer composites. Subsequently, we give the reasoning behind using preconstructed three-dimensional graphene networks for fabricating thermally conductive polymer composites and highlight their potential applications. Finally, our insight into the existing bottlenecks and opportunities is provided for developing preconstructed porous architectures of graphene and their thermally conductive composites.

Synergy of copper Selenide/MXenes composite with enhanced solar-driven water evaporation and seawater desalination

Despite significant of solar energy to power water evaporation in seawater desalination, the commercial application of this technology is limited by the poor light absorption and low photothermal conversion of existing photothermal materials. Herein, we report a simple method for solar-driven water evaporation using a device comprising Cu_2-xSe/Nb₂CT_x nanocomposites supported by a glass microfiber membrane, which utilizes cotton thread as water transport pathway. The proposed device demonstrates excellent light absorption, water transportation, and thermal management. Benefiting from the strong synergetic photothermal effect of Cu_2-xSe and Nb₂CT_x, the Cu_2-xSe/Nb₂CT_x nanocomposites function as an efficient solar absorber with excellent photothermal conversion efficiency. The rough surface, low thermal conductivity and good hydrophilicity of glass microfiber membrane could maximize light capture, limit heat loss, and timely replenish water during the water evaporation process. When evaluated as a water evaporation system for outdoor seawater desalination, the system achieved a water evaporation of 12.60 kg·m^-2 within 6 h. High fresh water generation rate is an important embodiment of high photothermal conversion efficiency. This study demonstrates a new route for designing solar desalination devices with high photothermal conversion properties.

Hierarchical WO3-x Ultrabroadband Absorbers and Photothermal Converters Grown from Femtosecond Laser-Induced Periodic Surface Structures

Oxygen-vacancy-rich WO3-x absorbers are gaining increasing attention because of their extensive absorbance-based applications in near-infrared shielding, photocatalysis, sterilization, interfacial evaporator and electrochromic, photochromic, and photothermal fields. Thermal treatment in an oxygen-deficient atmosphere enables us to prepare WO3-x but lacks the capacity for finely manipulating the grown structures. In this work, we present that laser-induced periodic surface structure (LIPSS) obtained by femtosecond laser ablation is a good template to grow various hierarchical WO3-x ultrabroadband absorbers and photothermal converters by thermal oxidation annealing in air. Increasing annealing temperature from 600 to 1000 °C allows the manipulation of WO3-x crystal sizes from ∼70 nm to ∼4 μm, accompanied by a color transition from brown to dark blue and finally to yellow. Benefiting from annealing-induced surface cracks and phase transition into WO3-x (containing both WO3 and W18O49) at 600 °C, excellent UV-vis-NIR-MIR ultrabroadband absorbers were produced: >90% UV-NIR absorbance (0.3-2.5 μm) and 50-90% MIR absorbance (2.5-16 μm), much better than most W-based metamaterial absorbers. The higher the annealing temperature (1000 > 800 > 600 °C), the better the photothermal performances (sample temperature as the indicator) of annealed interfaces due to the increased oxidation rates and resultant thicker oxide layers (6, 150, and 507 μm), a trend which is more apparent upon the irradiation of high-density (3160 mW/cm2) and ultrabroadband (200-2500 nm) light but much less apparent for shorter-band (200-800, 420-800, 800-2500 nm, etc.) and less-intensity (1694, 1540, 1460 mW/cm2, etc.) light irradiation. This phenomenon indicates that (1) higher-performance ultrabroadband absorbers possess a higher photothermal conversion capacity; (2) thicker-WO3-x oxide layer converters are more effective in preserving photothermal heat; and (3) both the W-LIPSS and metal tungsten substrate can quickly dissipate the photothermal heat to inhibit heat accumulation in the oxide photothermal converters. It is also proved that ablation-induced high-pressure shockwaves can produce deformation layers in the subsurfaces to release annealing-induced stresses, beneficial for the formation of less-cracked non-stoichiometric WO3-x interfaces upon annealing. High-pressure shockwaves are also capable of inducing grain refinement of LIPSS, which facilitates a homogeneous growth of small non-stoichiometric metal-oxide crystals upon annealing. Our results indicate that femtosecond laser ablation is a convenient upstream template-fabrication technique compatible with the thermal oxidation annealing method to develop advanced functional oxygen-vacancy metal-oxide interfaces.

The emerging development of solar evaporators in materials and structures

To tackle the increasingly severe freshwater resource scarcity problem, desalination using solar evaporators is potentially an effective approach. This article reviews the research progress of solar evaporators in recent years, including materials, structures, and performance evaluations. In terms of material research, this article introduces the mechanism of photothermal conversion of metallic, semiconductor, polymeric, and carbon-based materials and their applications in the research of solar evaporators. The structure design of solar evaporators that can improve the photothermal conversion efficiency and water transport efficiency are summarized in detail. Regarding the evaluation of the evaporator performance, common evaluation methods for steam efficiency and environmental benefits of solar evaporators were introduced. Finally, this article analyzes the current problems of evaporators and proposes a prospect for the development of new types of high-efficiency evaporators.

Mechanically robust biomass-derived carbonaceous foam for efficient solar water evaporation

The biomass-derived carbonaceous foam with excellent mechanical strength and evaporation efficiency has promising potential for practical interfacial solar water treatment.

Metal-free functionalized carbonized cotton for efficient solar steam generation and wastewater treatment

Water desalination via solar steam generation is one of the most important technologies to address the increasingly pressing global water scarcity. Materials for solar photothermal energy conversion are highly sought after for their cost savings, environmental friendliness and broad utility in many applications including domestic water heating and solar-driven desalination. Herein, we report the successful development of metal-free, low weight and cost effective functionalized carbonized cotton (CC) fibers for efficient solar water desalination and wastewater treatment. The CC fibers with nearly full solar spectrum absorption, efficient photo-thermal conversion and low-cost could provide excellent alternatives to the high-cost plasmonic-based materials for solar water desalination. We also report on a novel and simple device to mitigate the issues associated with conductive heat loss by utilizing the economically viable carbonized cotton materials as an irradiation surface placed on a low-density polyethylene foam that floats on the surface of seawater. The CC solar steam generation device exhibits average water evaporation rates of 0.9, 6.4 and 10.9 kg m^-2 h^-1 with impressive solar-to-vapor efficiencies of 59.2, 88.7 and 94.9% under 1, 5 and 8 sun illumination, respectively. Moreover, the device displays excellent durability showing stable evaporation rates over 10 steam generation cycles under 5 sun of solar intensity. Furthermore, the applicability of the CC device for the removal of organic dyes from contaminated water through solar steam generation is also demonstrated. The low-cost, simple design, high solar thermal evaporation efficiency, excellent stability and long-term durability make this CC device a perfect candidate for applications in seawater desalination and wastewater treatment by solar steam generation.

Design of a Separated Solar Interfacial Evaporation System for Simultaneous Water and Salt Collection

Solar-driven interfacial evaporation (SIE) is very promising to alleviate the freshwater scarcity issue. However, salt deposition on the sample surface will reduce evaporation performance, and compromised light absorption will result in a low water collection rate in conventional SIE apparatuses. Here, we report the design of a separated SIE system composed of a polypyrrole@Co₃O₄@aluminum sheet and a T-shaped superhydrophilic polyethylene/polypropylene nonwoven fabric right under the sheet. The photothermal surface exposed outside the closed SIE system is separated from the evaporation surface. Thus, salt fouling of solar evaporators is thoroughly avoided and the freshwater collection rate is greatly enhanced. Compared with conventional SIE systems, the separated SIE system has many advantages: simultaneous water and salt collection, a long-term stable evaporation rate even for concentrated brine (1.25 kg m^-2 h^-1 under 1 kW m^-2 (1 sun) illumination, 15 wt % NaCl_(aq), ≥120 h), high salt collection efficiency (≥97%), and a high water collection rate under natural sunlight, e.g., 0.72 kg m^-2 h^-1 in early spring (0.5-0.6 sun, 19-24 °C) and 0.33 kg m^-2 h^-1 in cold winter (0.3-0.4 sun, -6 to 4 °C). We foresee that the separated SIE system holds great potential for practical freshwater and salt collection from seawater.

Efficient Solar-Driven Water Purification Based on Biochar with Multi-Level Pore Bundle Structure for Preparation of Drinking Water

Water is an important source for humankind. However, the amount of available clean water has rapidly reduced worldwide. To combat this issue, the solar-energy-driven evaporation technique is newly proposed to produce clean water. Here, biochar derived from sorghum stalk with a multi-level pore bundle structure is utilized to fabricate a solar-driven evaporator for the first time. The biochar displays rapid water transfer and low thermal conductivity (ca. 0.0405 W m⁻¹ K⁻¹), which is vitally important for such an application purpose. The evaporation rate and energy conversion efficiency of the solar evaporator based on carbonized sorghum stalk can achieve up to 3.173 kg m⁻² h⁻¹ and 100%, respectively, which are better than most of the previously reported biomass materials. Furthermore, the carbonized sorghum stalk also displays good resistance to salt crystallization, anti-acidic/basic, and organic pollutants by producing drinking water using seawater, acidic/basic waste water, and organic polluted water, respectively. The direct application of processed water in food production was also investigated. The present solar steam evaporator based on the carbonized sorghum stalk has the potential to create practical drinking water production by using various water sources.

Carbon Materials for Solar Water Evaporation and Desalination

Seawater desalination is viewed as a promising solution to world freshwater scarcity. Solar assisted desalination is proposed to overcome the high energy consumption in current desalination technologies, as it uses abundant and sustainable solar energy as the only energy input. Interfacial solar vapor generation (SVG) has attracted considerable research interest due to its high energy conversion efficiency, simple implementation, and cost-effectiveness. Among all the candidate materials for solar evaporators, carbon-based materials stand out due to their intrinsic high solar absorption, highly tunable structure, easy preparation, low cost, and earth-abundancy. In this review, the recent progress on carbon-based materials for the development of interfacial SVG is summarized. First, a brief introduction to the basic design principles of the interfacial SVG system is presented. Then, recent efforts in carbon-based solar evaporators, from artificial structures to bioinspired configurations, focusing on their structure-function relationship are highlighted. Strategies for designing antisalt-fouling desalination systems are also summarized. Last, the challenges and opportunities of carbon-based materials for solar evaporation technology are elaborated.

Harvesting Light To Produce Heat: Photothermal Nanoparticles for Technological Applications and Biomedical Devices

The photothermal properties of nanoparticles (NPs), that is, their ability to convert absorbed light into heat, have been studied since the end of the last century, mainly on gold NPs. In the new millennium, these studies have developed into a burst of research dedicated to the photothermal ablation of tumors. However, beside this strictly medical theme, research has also flourished in the connected areas of photothermal antibacterial surface coatings, gels and polymers, of photothermal surfaces for cell stimulation, as well as in purely technological areas that do not involve medical biotechnology. These include the direct conversion of solar light into heat, a more efficient sun-powered generation of steam and the use of inkjet-printed patterns of photothermal NPs for anticounterfeit printing based on temperature reading, to cite but a few. After an analysis of the photothermal effect (PTE) and its mechanism, this minireview briefly considers the antitumor-therapy theme and takes an in-depth look at all the other technological and biomedical applications of the PTE, paying particular attention to photothermal materials whose NPs have joined those based on Au.

g-C3N4/MoS2 based floating solar still for clean water production by thermal/light activation of persulfate

Currently, seawater desalination based on air-water interface solar heating has triggered significant research interests because it effectively makes use of the solar energy and avoids fossil fuel consumption. However, to prevent the volatile organic compounds (VOCs) from volatilizing with water vapor which later will liquefy and enter the condensed freshwater is still a challenge. In this work, a g-C₃N₄/MoS₂ based floating solar still (CM-FSS) combined with thermal/light activation of persulfate (PS) at air-water interface was applied for clean freshwater production for the first time. The CM-FSS was composed of a g-C₃N₄/MoS₂ top layer for solar absorption, simultaneous thermal/light activation of PS and then VOCs degradation at air-water interface, a floating layer of expandable polyethylene (EPE) foam for heat isolation, and a transport channel of air-laid paper (ALP) for seawater and PS solution delivery. The water evaporation rate of the CM-FSS was measured at 1.23 kg m^-2 h^-1 under 1 kW m^-2, which is 4.09 times higher than that of pure water without an evaporator. With the assistance of g-C₃N₄/MoS₂ photocatalytic degradation and thermal/light activation of PS at the air-water interface, a high removal efficiency of a selected model VOCs pollutant of nitrobenzene (NB) could reach to 98.2% in condensed freshwater. Finally, when real seawater samples were employed as source water for solar distillation, the typical water-quality indices such as salinity, turbidity, anions, cations and organics of the condensed freshwater were below the limit values of the Standards for Drinking Water Quality in WHO, US EPA and China.