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Interfacial solar steam generation is considered as economical and more effective implementation of Solar steam generation (SSG) where solar energy is concentrated at the liquid surface via the utilization of heat localization materials (HLM). Herein we report the fabrication of an HLM constituted of a nanocomposite absorber of graphitic carbon nitride (g-C3N4) and covellite copper sulfide (CuS) supported on a mixed cellulose ester membrane, with a substrate of air laid paper-wrapped polystyrene foam. This structure allowed for strong broad-spectrum absorbance, increased hydrophilic character and minimal thermal losses. The HLM system absorbed 98% of the material and had an evaporation rate of 2.58 kgs per square meter per hour. This is twice the evaporation rate of water tested under the same conditions. Moreover, as fabricated HLM was also incorporated in a solar still in order to assess its practical performance in solar distillation. Initial studies proved that HLM modified solar still was more effective than conventional solar stills.

The global increase in population, the phenomenon of climate change, the issue of water pollution and contamination, and the inadequate management of water resources all exert heightened strain on freshwater reserves. The potential utilization of the interfacial solar steam generation (ISSG) system, which utilizes photothermal conversion to generate heat on material surfaces for wastewater purification and desalination purposes, has been successfully demonstrated. Textile-material-based ISSG devices, including (woven, nonwoven, and knitted) fabrics and electrospinning membranes, exhibit distinct properties such as a rough surface texture, high porosity, significant surface area, exceptional flexibility, and robust mechanical strength. These characteristics, combined with their affordability, accessibility, and economic viability for widespread implementation, make them extremely attractive for applications in SSG. In this review, a comprehensive analysis of the emerging concepts, advancements, and applications of textile materials, such as woven, nonwoven, and knitted fabrics and electrospun membranes, in ISSG for wastewater purification and desalination is presented. We also emphasize significant obstacles and potential prospects in both theoretical investigations and real-world implementations, aiming to contribute to future advancements in the domain of textile-material-based interfacial evaporation in wastewater purification and desalination. Furthermore, the drawbacks and the challenges of ISSG systems are also highlighted. [ABSTRACT FROM AUTHOR]

Interfacial solar steam generation (ISSG) offers a sustainable and environmentally friendly strategy for addressing the energy and water crises. In this study, we fabricated a highly efficient and cost-effective plasmonic photoabsorber for ISSG of seawater by coating silver nanoparticles (Ag NPs) on pinecone (PC). The PC with low thermal conductivity and numerous aligned microchannels for fast water transport, provides sufficient water supply and reduces the bulk heat loss. In addition, Ag NPs strongly absorb solar radiation through the surface plasmon resonance effect. Using Ag/PC under 1 sun (1 kW m–2), we achieved an evaporation flux and efficiency of 1.82 kg m–2 h–1 and 100%, respectively. Moreover, Ag/PC removed more than 99% of Na+, K+, Mg2+, and Ca2+ ions from seawater. The plasmonic PC also exhibited excellent cycling during 10 cycles efficiency of ISSG. Furthermore, treatment of paper industry wastewater with Ag/PC resulted in a significant decrease in the concentration of ions. [ABSTRACT FROM AUTHOR]

In this pioneering work, we propose a manufacturing plan for a 3D hollow hemispherical solar selective absorber (HSSA). The HSSA stands out as a superior choice compared to planar absorbers, thanks to its numerous benefits and wide-ranging applications, particularly in solar harvesting and photothermal desalination. Importantly, HSSAs reduce radiative losses by emitting thermal radiation along their curved surfaces, which enhances concentration ratios and minimizes these losses. This study addresses the intricacies of fabricating the HSSA's 3D convex shape. Our approach draws inspiration from a set of 2D flat solar selective absorbers (SSAs), each fine-tuned to adapt angles and intensities in response to solar radiation. These optimized SSAs are then arranged within a grid shell framework. As an illustrative example, we consider the widely-used selective coating W/Al2O3-W/Al2O3. We optimize parameters, including layer thicknesses and the incorporation of metal in the absorber, to attain optimal values for photothermal conversion output under varying oblique incidence angles. For this optimization process, we employ the non-parametric particle swarm algorithm known as 'phasor,' recognized for its autonomous search for global optima in complex and multimodal optimization problems. Our calculations yield a remarkable photothermal conversion efficiency, reaching up to 0.966429. This research is driven by the aspiration to maintain such high efficiency, even in the face of fluctuations in solar radiation incidence and intensity throughout the day. Simplifying calculations, we divide the hemisphere into five spots, optimizing each for peak performance according to its positioning. These collective efforts and innovations culminate in the development of a compact solar water desalination system, engineered for efficient operation, even in the presence of one sun. [ABSTRACT FROM AUTHOR]

A scalable, cost-effective, maintainable, porous, and high-efficient interfacial solar steam generation (ISSG) device is of great importance to address the challenge of water scarcity. The performance of Ag or/and Ni doped g-C3N4 as efficient photothermal materials coated on poplar wood in ISSG of seawater is evaluated. The photothermal conversion efficiency of g-C3N4 as a photothermal material improves by doping it with Ag or Ni due to the surface plasmon resonance effect of these metals. The Ag doped g-C3N4 represents more solar evaporation efficiency with respect to Ni doped g-C3N4 owing to its stronger absorption in visible and infrared regions. The highest evaporation flux of 3.72 kg m−2 h−1 is achieved for the wood coated by Ag doped g-C3N4 under 3 sun. For this photothermal material, the concentration of Na+ of Caspian seawater decreases from 3150.2 to 3.8 mg L−1. The Ag doped g-C3N4/wood evaporator device is exhibited a stable water generation ability in ten evaporation cycles. [ABSTRACT FROM AUTHOR]

[Display omitted] • The bilayer aerogel was obtained by cellulose skeleton with PVAP hydrogel and CNT. • An evaporation rate of 4.02 kg m−2 h−1 was achieved by CPC under 1 sun irradiation. • Water evaporation increased to 11.37 kg m−2 h−1 with convective flow of 2.0 m s−1. • The 10.70 kg m−2 h−1 was obtained in salt water by utilization multiple energy. • Cost-effectiveness and significant desalination highlight wide application of CPC. Interfacial solar steam generation (ISSG) provides a sustainable approach of clean water production through desalination and water purification. It is still needed to pursue a fast evaporation rate, high-quality freshwater production, and low-cost evaporators. Herein, a three-dimensional (3D) bilayer aerogel was fabricated using cellulose nanofiber (CNF) as a skeleton filled with polyvinyl alcohol phosphate ester (PVAP), and carbon nanotubes (CNT) as a light absorbing material in the top layer. The CNF/PVAP/CNT aerogel (CPC) had broadband light absorption ability and exhibited an ultrafast water transfer rate. The lower thermal conductivity of CPC effectively confined the convert heat in the top surface and minimized heat loss. Additionally, a large amount of intermediate water caused by water activation decreased the evaporation enthalpy. Under 1 sun irradiation, the CPC-3 (3.0 cm height of CPC) achieved a high evaporation rate of 4.02 kg m−2 h−1 with an energy conversion efficiency of 125.1%. The additional convective flow and environmental energy made CPC achieve an ultrahigh evaporation rate of 11.37 kg m−2 h−1, surpassing 673% of the solar input energy. More importantly, the continuous solar desalination and higher evaporation rate (10.70 kg m−2 h−1) in seawater revealed that CPC was a promising candidate for practical desalination. Outdoor cumulative evaporation was up to 73.2 kg m−2 d−1 in weak sunlight and lower temperature, which would meet the daily drinking water demands of 20 people. The excellent cost-effectiveness of 1.085 L h−1 $−1 presented its potential for a wide range of practical applications, such as solar desalination, wastewater treatment, and metal extractions. [ABSTRACT FROM AUTHOR]

Interfacial solar steam generation (ISSG) is a novel and potential solution to global freshwater crisis. Here, based on a facile sol-gel fabrication process, we demonstrate a highly scalable Janus aramid nanofiber aerogel (JANA) as a high-efficiency ISSG device. JANA performs near-perfect broadband optical absorption, rapid photothermal conversion and effective water transportation. Owning to these features, efficient desalination of salty water and purification of municipal sewage are successfully demonstrated using JANA. In addition, benefiting from the mechanical property and chemical stability of constituent aramid nanofibers, JANA not only possesses outstanding flexibility and fire-resistance properties, but its solar steaming efficiency is also free from the influences of elastic deformations and fire treatments. We envision JANA provides a promising platform for mass-production of high-efficiency ISSG devices with supplementary capabilities of convenient transportation and long-term storage, which could further promote the realistic applications of ISSG technology.

Aiming to achieve the goals of high evaporation rate, eco-friendly and facile preparation with low-cost raw materials, a type of photothermal hydrogel which use tannic acid-iron ion complexes as photothermal material and gelator was successfully synthesized by a facile blending method. The photothermal hydrogel can achieve a high rate of 1.897±0.11 kg·m−2·h−1 and an energy efficiency of 89.7±2.73% under 1 sun irradiation and has been proven to realize efficient sewage treatment and desalination in outdoor condition. [Display omitted] • The tannic acid-Fe3+ complex is used as photothermal material and gelators. • A photothermal hydrogel evaporator is prepared by a blending method. • All the raw materials are eco-friendly and low-cost. • A high evaporation rate of 1.897 ± 0.11 kg·m−2·h−1 under 1 sun irradiation is achieved. The field of solar vapor generation has developed rapidly in recent years, but achieving the goals of a high evaporation rate, eco-friendliness and rapid preparation with low-cost raw materials is still a challenge. In this work, a type of photothermal hydrogel evaporator was prepared by blending eco-friendly poly(vinyl alcohol), agarose, Fe3+ and tannic acid (TA) together, in which the tannic acid-ferric ion (TA*Fe3+) complexes served as photothermal materials and effective gelators. The results indicate that the TA*Fe3+ complex exhibits excellent gelatinization ability and light-absorption performance, which leads to a compressive stress of 0.98 MPa at 80% strain and up to 85% light absorption ratio in the photothermal hydrogel. For interfacial evaporation, a high rate of 1.897 ± 0.11 kg·m−2·h−1 corresponding to an energy efficiency of 89.7 ± 2.73% under 1 sun irradiation is achieved. Moreover, the hydrogel evaporator exhibits high stability in a 12-hour test and a 20-cycle test without a decline in evaporation performance. The outdoor testing results show that the hydrogel evaporator can achieve an evaporation rate of > 0.70 kg/m2 and effectively purify wastewater treatment and seawater desalination. [ABSTRACT FROM AUTHOR]

[Display omitted] • Photothermal P-NMO/NF structure is well designed and successful synthesized. • Broadband P-NMO/NF enables efficient thermal management and adequate water transport. • P-NMO/NF evaporator achieves high evaporation rate and evaporation efficiency. • P-NMO/NF evaporator achieves efficient water purification for freshwater production. • P-NMO/NF shows great potential for practical solar evaporation under natural sunlight. Interfacial steam generation by harnessing renewable solar energy has been recognized as a sustainable solution to global freshwater crisis. A promising evaporator with key components of high spectral absorption, efficient thermal management and adequate water transport is highly desired. In the present study, an integrated design for three-in-one functionality is achieved by simply loading Ni 5 P 4 -NiMoO x (P-NMO) on a macroporous nickel foam (NF) carrier. In situ embedding broadband Ni 5 P 4 absorber into insulating NiMoO x enables efficient photothermal conversion and heat localization. Benefiting from proper thermal management and abundant water transmission, P-NMO/NF exhibits the excellent performance for interfacial steam generation with a high evaporation rate of 1.49 kg m−2h−1 and evaporation efficiency of 93.0 % under one sun irradiation. Furthermore, the obtained P-NMO/NF is proven to be applicable for high-efficiency freshwater production in seawater desalination and wastewater purification, showing great potential for practical solar evaporator under natural environmental conditions. [ABSTRACT FROM AUTHOR]

Interfacial solar steam generation (ISSG) is a sustainable and environmental‐friendly technology for seawater desalination and wastewater purification using green and sustainable solar energy. Herein, a robust and efficient interfacial solar steam generation device or photoabsorber for ISSG of seawater and wastewater treatment was designed by coating wood with trace amount of Pd nanoparticles (NPs) and reduced graphene oxide (RGO). High evaporation flux of 5.25 kg m−2 h−1 was achieved by Pd20/RGO80/wood (a piece of wood was coated with 80 and 20 mg L−1 of Pd NPs and RGO as a top and bottom layer, respectively) under 3 kW m−2. The value of electrical conductivity of seawater decreased from 6000.0 to 5.8 μS cm−1 after desalination. The durability test showed the photoabsorber was stable for 30 cycles. The total cost to evaporation rate of the device was calculated as 0.29± ${\pm }$ 0.003 USD/(cm3 h−1). The photoabsorber also showed excellent performance in wastewater treatment in removal of dyes of methylene blue and Reactive blue 5. Also, the concentration of heavy metals of Zn2+, Cd2+, Pb2+, Fe2+, Ni2+, and Cr6+ reduced from 1000 ppm to near zero in the presence of photoabsorber. [ABSTRACT FROM AUTHOR]

Interfacial solar steam generation (ISSG) has drawn considerable interest as an emerging technology for seawater desalination. However, designing simple and cost-effective solar evaporators with high salt resistance and impressive evaporation rates remains a significant challenge. Inspired by tree rings, a three-dimensional (3D) solar evaporator (PPy-RWCF) was fabricated by rolling polypyrrole-decorated waste cotton fabric (PPy-WCF) into a cylinder. The synergistic effect of polypyrrole (PPy) and interstices within the waste cotton fabric (WCF) allows the PPy-RWCF to absorb around 99.00 % of sunlight. The PPy-RWCF, with an exposure height of 3 cm, achieves an excellent evaporation rate of 2.36 kg m−2 h−1 under 1-solar intensity. Besides, the vertical water channels within PPy-RWCF allow rapid solution transport, enabling it to withstand 20 wt% brine with an evaporation rate of 2.05 kg m−2 h−1. Prolonged outdoor desalination testing has demonstrated that a 1 m2 PPy-RWCF can generate approximately 10 kg of freshwater daily. This study proposes a sustainable approach to the development of solar evaporators utilizing WCF for desalination of high-salinity water. [Display omitted] • A solar evaporator (PPy-RWCF) is fabricated by simply rolling polypyrrole-decorated waste cotton fabric. • PPy-RWCF-100-3 achieves an excellent evaporation rate of 2.36 kg m−2 h−1. • PPy-RWCF-100-3 with vertical water channels makes it withstand 20 wt% brine. • 1 m2 of PPy-RWCF consistently produces about 10 kg of freshwater per day. [ABSTRACT FROM AUTHOR]

A smart sponge with a web-like 3D interconnected porous structure was prepared by surface atom transfer radical polymerization (SATRP) for liquid transportation and continuous solar-powered seawater evaporation. The smart sponge can achieve oil directional transport and automatically controls desorption by thermo-controlled reversible switching wettability. In addition, the synergistic effect of high light-to-heat conversion capacity and excellent salt resistance resulted in efficient and continuous evaporation. The prepared sponge showcases the great potential for developing a new class of materials for environmental restoration and water regeneration. [Display omitted] A better knowledge for the design and synthesis of low-cost, novel porous materials is highly desirable in various fields such as recyclable solar desalination and liquid recycling. Herein, a polydimethylsiloxane-based sponge with a web-like three-dimensional (3D) interconnected porous structure was developed for effective recovery of liquids and the continuous interfacial solar steam generation (ISSG). The sponge is capable of conducting directional transport of oil or organic solvents at temperatures above 32 °C while automatically controlling the desorption of the organic phase below 28 °C. The synergistic combination between high light absorption (above 95 %) and light-to-heat conversion efficiency (99.87 %) resulted in a considerably high seawater evaporation rate (1.66 Kg m−2h−1) under 1 sun. The self-regeneration of the evaporator is facilitated by the salt barrier function of the large channels of the smart sponge with high hydraulic conductivity. This sponge can maintain a maximum evaporation rate up to the 5 consecutive days operation with the co-benefit of real-time regeneration and the reversible switching of the wettability. The reusable smart sponge evaporators are highly efficient in generating clean water from seawater with satisfactory ion rejection rates (above 99.6 %). As such, the prepared sponge shows great potential in environmental restoration, metal recovery, and water regeneration. [ABSTRACT FROM AUTHOR]

[Display omitted] Although the evaporation efficiency of photothermal materials (PMs) in pure water and brine solutions has been extensively studied, there few research on the performance in complex oily wastewater. Herein, a new monolithic solar steam generator derived from kapok fiber-based MXene composite aerogel (named as KFs-MXene) was fabricated by dipping the aerogels (KFs) which composed of kapok fiber and sodium alginate (SA) as substrates in the suspension of MXene. Benefitting from the outstanding light absorption (about 97%), better thermal insulation (thermal conductivity, 0.05039 W m−1 K−1), abundant porosity (95.60%) and rapid water transportation. KFs-MXene show good interfacial solar steam generation (ISSG) performance, resulting in a high water evaporation rate of 1.47 kg m−2h−1 with an outstanding evaporation efficiency of 90.4% under 1 kW m−2 irradiation. To improve the antifouling performance of KFs-MXene, chemically hydrophilic and oleophobic modification was applied, making the KFs-MXene can also be widely used in oily wastewater. Under 1 kW m−2 illumination, the evaporation rate and energy conversion efficiency of KFs-MXene with hydrophilic and oleophobic modification (O-KFs-MXene) in 1 wt% oily water can reach to 1.40 kg m−2h−1 and 82.87%, and the evaporation efficiency and rate of O-KFs-MXene remain stable in the continuous 6 h solar driven interface evaporation process. [ABSTRACT FROM AUTHOR]

Interfacial solar steam generation (ISSG) employed for seawater desalination and wastewater purification shows great promise to alleviate global freshwater scarcity. However, simultaneous optimization of water transfer direction in a cost-effective and reliable ISSG to balance thermal localization, salt accumulation, and resistance to oilfouling represents a rare feat. Herein, inspired by seabird beaks for unidirectional water transfer, eco-friendly and cost-effective plant extracts, sodium alginate, and tannic acid, are selected for crafting an innovative Sodium Alginate-Tannic Acid Hemispheric Evaporator (STHE). The STHE aligned with centripetally tapered channels ensures one-directional water flow and effectively inhibits downward heat transfer, thereby boosting energy efficiency. Additionally, the integration of one-way water supply in tapered channels with interfacial evaporation of STHE, mimicking plant transpiration, collaboratively facilitates upward water transfer for a reliable solar-driven water evaporation rate of ≈2.26 kg m -2 h -1 under one sun irradiation. Even in a brine of 15.0 wt % solution, no salt crystals are observed on the surface of STHE. Hemispheric structure and superhydrophilicity are conducive to oil repellence. This work provides pivotal inspiration for constructing next-generation solar generators of high-efficiency, salt-tolerance, and anti-oil-fouling., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

[Display omitted] • An efficient inclined solar evaporator based on polypyrrole/polydopamine was designed. • The evaporator exhibited an evaporation rate of 3.02 kg m−2 h−1 under 1 sun. • A salinity gradient can be obtained by the interfacial evaporation process. • The system can achieve an open-circuit voltage of 56 mV during electricity generation. Water-electricity cogeneration using solar energy is an innovative technology to address global freshwater shortages and energy demands. Here, we designed an inclined evaporator based on polypyrrole/polydopamine photothermal materials for efficient water evaporation and electricity cogeneration. Due to the ingenious inclined structure of the evaporator, the water transport was highly promoted by gravity and siphon effect. This process not only improves the evaporation flux of water, but also create a salinity gradient that can be used for further electricity generation. The designed inclined PPy/PDA@MF evaporator exhibits an evaporation flux of 3.02 kg m−2 h−1 under one sun irradiance and achieves an open-circuit voltage of 56 mV during the electricity generation. [ABSTRACT FROM AUTHOR]

Solar steam generation (SSG) utilizes green, widespread solar energy as an energy source, making it a promising technology for seawater desalination and wastewater purification. Interfacial SSGs (ISSGs) localize the heat converted from solar energy at the air-water interface to enhance interfacial temperature and decrease heat loss to bulk water, leading to a significant increase of solar-to-vapor conversion efficiency. However, ISSGs still face significant limitations in fabrication cost, overall efficiency, and biodegradability. Bio-based ISSGs have attracted much attention for their sustainability and low cost. A large number of high-efficiency bio-based ISSGs have been developed in the past decade. Reviews on bio-based ISSGs are still rare. This review first introduces the state-of-art development of the key processes and general principles of ISSG devices, including energy sources, photothermal conversion, thermal management, water supply, evaporation enthalpy, and durability. All these processes are crucial to the final performance of ISSGs, requiring careful design and tuning to achieve high efficiency. Then a variety of bio-based ISSGs are elaborated upon, such as those made from wood, bamboo, lotus, rice, pomelo peel, sunflower, cuttlefish ink, mushroom, and algae. Bio-based ISSGs excel in sustainability and low cost but still suffer from low efficiency and short durability. The use of biological materials with water collection abilities is also discussed for designing water collectors. Finally, the challenges and promising prospects of bio-based ISSGs are discussed, including efficiency, extraction of bio-based materials, stability, durability, and condensation rates. This review aims to facilitate and inspire the rapid development of bio-based ISSGs. [Display omitted] • ISSG is a promising method for desalination and waste treatment. • ISSG enhances efficiency by localizing heat at the air-water interface. • Bio-based ISSG attracts much attention due to its sustainability and low cost. • Key processes and general principles of ISSG are introduced. • A variety of bio-based ISSGs reported in recent years are elaborated. [ABSTRACT FROM AUTHOR]

• Heat pipes are used to separate light-absorbing and evaporation surfaces due to their efficient heat transfer. • Salt accumulation and steam obstruction issues on the light-absorbing surface are overcome. • A hydrophobic copper plate is used as the condensation surface for efficient water collection. • Evaporation rate of 1.17 kg m−2h−1 and water production rate of 0.45 kg m−2h−1 under 1 sun irradiation are achieved. Interfacial solar steam generation (ISSG) holds great potential for seawater desalination, and wastewater treatment. However, salt accumulation on the evaporation surface and low condensation rate notoriously degrade the performance of traditional interfacial evaporators during prolonged operation. To tackle the issues, this study introduces a general absorption-evaporation decoupled device enabled by a heat pipe assembly. Black acetate fabric is tightly attached on one side of the heat pipe surface as a photothermal layer, while a hydrophilic cellulose film is integrated on the other side with a siphon architecture, serving as an evaporation surface. The heat pipes enable efficient heat transfer from the light-absorbing side to the evaporation side of the device, thereby achieving a significant evaporation rate of 1.17 kg m−2h−1 under one-sun irradiation intensity. In addition, the device demonstrates excellent evaporation performance under different saline concentrations and maintains long-term stable operation. Furthermore, a hydrophobic copper plate is adopted as the condensation surface, leading to an improved water yield as high as 0.45 kg m−2h−1 with a steam-to-water efficiency of 38.5 %. The produced freshwater has also been proven suitable for agricultural use. Overall, the proposed decoupled design paves the way toward durable and efficient ISSG devices. [ABSTRACT FROM AUTHOR]

Interfacial solar steam generation is acknowledged as an extremely effective and environmentally friendly method of producing potable water. Nevertheless, significant challenges persist in the development of an evaporator capable of achieving heightened rates of evaporation, catalytic capabilities, resistance to bacterial proliferation, and effective light absorption across a broad spectrum. This article outlines the fabrication of a solar steam generator utilizing electrospinning technology and membrane evaporators constructed from α-Fe 2 O 3 /PAN (polyacrylonitrile) nanofibers. The integration of α-Fe 2 O 3 /PAN composite enhances both light absorption and heat generation. In sunlight, the maximum evaporation rate is 2.7 kg m−2 h−1, which is significantly more than the rate of today's cutting-edge solution-electrospun nanofiber-based evaporators. The electrospun mat has high catalytic activity and antibacterial properties, making it an important component in desalination. [ABSTRACT FROM AUTHOR]

Utilizing solar energy for interfacial solar steam generation and wastewater remediation is regarded as one of the sustainable approaches for alleviating clean water shortage. However, it is still a great challenge to comprehend all the requirements of efficient evaporation, salt resistance and wastewater treatment as well as low cost in one evaporator, thus hindering its large-scale practical application. Herein, in this work, an environmentally friendly and low-cost hierarchical porous architecture (APC@TMF) was prepared by assembling potassium citrate activated poplar catkin derived porous carbon (APC) into the porous structure of thermalized melamine formaldehyde resin sponge (TMF) by a simple dipping method. The APC@TMF integrates the advantages of APC and TMF, thus leading to good light absorption, low thermal conductivity, high hydrophilicity and fast water transport. As expected, APC@TMF exhibits a high evaporation flux of 2.28 kg m−2 h−1 with energy conversion efficiency of 96.3 % in seawater, which outperforms TMF, PVA/TMF, PVA/APC and recently reported evaporators. Beyond that, it demonstrates good performance for seawater desalination and wastewater remediation as well as high cost-effectiveness. APC@TMF hierarchical porous architecture, assembled by filling poplar catkin (APC) derived carbon into the porous structure of thermalized melamine formaldehyde resin sponge (TMF), is successfully prepared by a simple dipping method, exhibits outstanding solar-driven interfacial seawater evaporation and wastewater purification performance. [Display omitted] • APC@TMF was prepared by assembling biomass-derived carbon into thermalized sponge. • APC@TMF shows good performance in seawater desalination and wastewater remediation. • The hierarchical porous structure of APC@TMF helps reduce the evaporation enthalpy. [ABSTRACT FROM AUTHOR]

[Display omitted] Photothermal water evaporation provides a pathway towards a promising solution to global freshwater scarcity. Synergistic integration of functions in a material in diverse directions is a key strategy for designing multifunctional materials. Lanthanum-based perovskite complex oxides LaMO 3 (M = Ni and Co) have narrow band gaps with a high absorption coefficient. These functionalities have not been appropriately explored for photothermal energy conversion. Here, we synthesized nanostructured metallic LaNiO 3 and semiconducting LaCoO 3 and used them to design interfacial solar steam generators. Effective light absorption capability over the entire solar spectrum of these materials leads to a photothermal efficiency of the order of 83% for both materials. Using a cone-shaped 3D interfacial steam generator with a LaNiO 3 absorber, we achieved an evaporation rate of 2.3 kg m−2 h−1, corresponding to solar vapor generation efficiency of over 95%. To the best of our knowledge, this evaporation rate is higher than any oxide-based interfacial solar steam generator reported so far. Furthermore, we have also shown an effective way of using such evaporators for long-term seawater desalination. [ABSTRACT FROM AUTHOR]

The progression of photothermal materials with broad solar absorption and improved photothermal conversion efficiency is critical for developing interfacial solar steam generation (ISSG)‐based water desalination and purification systems. This green solar‐driven water vaporization technology has regained popularity as a sustainable solution to water shortage. Among many other photothermal materials, natural porous material‐based photothermal evaporators have piqued the interest of researchers owing to their biodegradability, abundance, low thermal conductivity, low cost, natural capillary mechanism, and hydrophilicity. In this review, recent advances in photothermal material design based on various natural porous materials are reported, systems considering contact mode and the water transportation route are categorized, optical absorbance is assessed, and thermal management issues and water purification as well as desalination applications are discussed. This review stimulates further investigation and research interest in the utilization of natural porous materials for large‐scale ISSG‐based application implementation. [ABSTRACT FROM AUTHOR]

Interfacial solar steam generation (ISSG) system has attracted extensive attention as a sustainable desalination technology because of its cost efficiency and zero fossil-energy consumption. Aiming at optimizing the desalination properties, materials and system design have been the current research focus. Recently, many novel bio-derived/bio-inspired design strategies were proposed owing to their highly efficient structures inherited from nature, which were fine-tuned over eons of evolution, as well as their low cost and ease of treatment. In this review, we are going to systematically report recent progress of various bio-derived/bio-inspired strategies in terms of optical design, wetting, thermal management, and overall system design, presenting an overview of the current challenges of bio-inspired materials in ISSG system and other application fields. This article is intended to provide a comprehensive review of recent developments about bio-derived/bio-inspired materials in ISSG system and conclude with suggestions regarding further research directions for performance enhancement through design of bio-derived/bio-inspired materials. [ABSTRACT FROM AUTHOR]

• An efficient bamboo-based evaporator achieving an excellent evaporation performance of 1.522 kg/m2 h with 94.4% conversion efficiency and sharp response time 80 s under one sun irradiance. • Efficient purification capacity was achieved towards insoluble matter and soluble humus, organic or inorganic matter in seawater with self-clean capacity. • Torrefaction simplifies the fabrication process, avoids property loss, structural damage, and makes maximum best use of natural bamboo. • Deepen investigates the synergy between water molecule transportation and photothermal transformation upon the air–water interface. Previous studies have explored interfacial solar steam generation (ISSG) for photothermal conversion and seawater purification via biobased solar-driven devices. Nevertheless, as the water transport and solar absorption were inadequate, the seawater purification of current devices is limited. Herein, we report an efficient bamboo-based evaporator that demonstrates the torrefaction bamboo and avoids fabrication defects, achieving an excellent evaporation performance of 1.522 kg/m2 h with 94.4% conversion efficiency and sharp response time 80 s under one sun irradiance. This evaporator provides a stable self-floating state with continuous micro-nano channels, which were significantly parallel with the air–water surface, generating more photothermal energy and sharper water molecule movement than current devices. Simultaneously, this bamboo-based evaporator leads effective seawater purification towards the insoluble matter, soluble humus, and organic or inorganic matter, removing 99.58% of dissolved solids with self-clean capacity. Theoretical simulations deepen the synergy between water transport and photothermal location, promising prospects for the future development of high-performance biobased evaporators to ensure clean fuel and freshwater challenges. [ABSTRACT FROM AUTHOR]

Abstract Solar‐driven water evaporation and valuable fuel generation is an environmentally friendly and sustainable way for clean water and energy production. However, a few bottlenecks for practical applications are high‐cost, low productivity, and severe sunlight angle dependence. Herein, solar evaporation with enhanced photocatalytic capacity that is light direction insensitive and of efficiency breakthrough by virtue of a three‐dimensional (3D) photothermal catalytic spherical isotopic evaporator is demonstrated. A homogeneous layer of microfluidic blow spun polyamide nanofibers loaded with efficient light absorber of polypyrrole nanoparticles conformally wraps onto a lightweight, thermal insulating plastic sphere, featuring favorable interfacial solar heating and efficient water transportation. The 3D spherical geometry not only guarantees the omnidirectional solar absorbance by the light‐facing hemisphere, but also keeps the other hemisphere under shadow to harvest energy from the warmer environment. As a result, the light‐to‐vapor efficiency exceeds the theoretical limit, reaching 217% and 156% under 1 and 2 sun, respectively. Simultaneously, CO2 photoreduction with generated steam reveals a favorable clean fuels production rate using photocatalytic spherical evaporator by secondary growth of Cu2O nanoparticles. Finally, an outdoor demonstration manifests a high evaporation rate and easy‐to‐perform construction on‐site, providing a promising opportunity for efficient and decentralized water and clean fuel production.

Solar‐driven water evaporation and valuable fuel generation is an environmentally friendly and sustainable way for clean water and energy production. However, a few bottlenecks for practical applications are high‐cost, low productivity, and severe sunlight angle dependence. Herein, solar evaporation with enhanced photocatalytic capacity that is light direction insensitive and of efficiency breakthrough by virtue of a three‐dimensional (3D) photothermal catalytic spherical isotopic evaporator is demonstrated. A homogeneous layer of microfluidic blow spun polyamide nanofibers loaded with efficient light absorber of polypyrrole nanoparticles conformally wraps onto a lightweight, thermal insulating plastic sphere, featuring favorable interfacial solar heating and efficient water transportation. The 3D spherical geometry not only guarantees the omnidirectional solar absorbance by the light‐facing hemisphere, but also keeps the other hemisphere under shadow to harvest energy from the warmer environment. As a result, the light‐to‐vapor efficiency exceeds the theoretical limit, reaching 217% and 156% under 1 and 2 sun, respectively. Simultaneously, CO2 photoreduction with generated steam reveals a favorable clean fuels production rate using photocatalytic spherical evaporator by secondary growth of Cu2O nanoparticles. Finally, an outdoor demonstration manifests a high evaporation rate and easy‐to‐perform construction on‐site, providing a promising opportunity for efficient and decentralized water and clean fuel production. [ABSTRACT FROM AUTHOR]

Interfacial solar steam generation (ISSG) is considered a green and inexpensive technology to solve water scarcity problems. Currently, it still needs to pursue a fast evaporation rate, high-quality fresh water production, and excellent mechanical properties. Herein, Janus aerogels with hydrophilic and hydrophobic structures were prepared by effective spraying of polydimethylsiloxane (PD on the upper surface of bacterial cellulose (BC) /carbon black (CB) /agar powder composites (named JBCA). After a series of experiments, the results showed that the obtained JBCA evaporator had a water evaporation rate of 1.83 kg m−2 h−1 under 1000 W m−2 solar radiation. Meanwhile, the same high evaporation rate (1.63 kg m−2 h−1) was obtained in high salinity (20 wt%) solution. More importantly, the ion removal rate for real seawater was more than 99 %. The results of outdoor evaporation experiments and sustainability analyses indicated that this low-cost material with Janus structure had great potential for practical applications. • A Janus aerogel (named JBCA) was prepared by spraying hydrophobic polydimethylsiloxane on a hydrophilic substrate. • The JBCA aerogel achieved an excellent evaporation rate of 1.83 kg m-2 h-1 in pure water. • In outdoeriments, daily freshwater production reached a maximum of 8.1 kg m-2 and a minimum of 4.82 kg m-2. • Low cost and environmental friendliness highlight the sustainability of JBCA aerogels. [ABSTRACT FROM AUTHOR]

Effective harnessing of renewable solar energy in interfacial solar steam generation (ISSG) is a promising solution for addressing freshwater scarcity worldwide. Therefore, the development of photothermal materials plays a pivotal role in achieving efficient ISSG performance. This paper reports on an innovative photothermal material, copper phosphate (Cu 3 P 2 O 8 ; CuPO), with broadband visible-to-near-infrared (Vis-to-NIR) absorption for ISSG. CuPO exhibited favorable characteristics, including extensive light absorption across the Vis to NIR spectrum (500–2200 nm), low thermal conductivity (0.64 W/m·K), high photon-to-heat conversion efficiency (87.9 %), and inherent hydrophilicity. When subjected to simulated sunlight (AM1.5G, 100 mW/cm2), the CuPO-coated polyurethane membrane demonstrated remarkable water evaporation performance (2.05 kg/m2·h) and ISSG efficiency (95.0 %). Notably, employing an ultraviolet cutoff filter (< 450 nm) revealed a substantial NIR absorption contribution of CuPO, surpassing 80 % of its overall performance. Moreover, the CuPO photothermal membrane exhibited durable ISSG performance over 25 cycles, underscoring the structural robustness and resilience of CuPO. Our findings offer a promising foundation for designing cost-effective, high-performance ISSG systems utilizing copper-based complex oxides. • Copper phosphate (Cu 3 P 2 O 8 ; CuPO) showed broadband and strong visible-to-near-infrared absorption properties. • CuPO exhibited low thermal conductivity, high photothermal efficiency, and inherent hydrophilicity. • Remarkable water evaporation performance (2.1 kg/m2·h) and ISSG efficiency (95.0 %) are demonstrated. • CuPO photothermal membrane exhibited durable and steady ISSG performance over 25 cycles. [ABSTRACT FROM AUTHOR]

[Display omitted] • Biomass-based hydrogel evaporators were prepared for desalination. • The combination of SA hydrogel and CP lamella boosts evaporation performance. • The superhydrophilic nature of the evaporator prevents salt deposits. Solar-driven interfacial evaporation has great potential for seawater and wastewater purification treatment due to its high evaporation efficiency and environmental friendliness. However, salt deposition may occur during the actual desalination process, which can affect the performance and lifespan of the evaporator. In this study, a hydrogel (H) evaporator based on biomass material was developed, which encapsulated carbonized potato (CP) lamella into the sodium alginate (SA) framework (abbreviated as SA-H@CP). Due to the excellent solar energy collection ability of two-dimensional carbonized potato lamella, combined with the strong water transport capability of the hydrogel, the evaporator exhibited efficient photothermal conversion ability and super hydrophilic properties that resulted in excellent salt resistance. The SA-H@CP evaporator can achieve an evaporation rate of 1.36 kg m−2 h−1, and an efficiency of 85 % in pure water under 1 sun illumination. The concentration of salt ions in the produced freshwater was much lower than the drinking water standard set by the World Health Organization (WHO). This work provides a solution for the large-scale promotion of solar-driven interfacial evaporation technology for seawater desalination. [ABSTRACT FROM AUTHOR]

• This research investigates the enhanced near-infrared absorption of Cs 0.32 WO 3 nanoparticles for efficient interfacial solar steam generation. • Cs 0.32 WO 3 nanoparticles effectively converted solar energy into heat, resulting in efficient interfacial steam generation. • The synthetic nanoparticles were incorporated into a porous membrane, which showed a high evaporation rate of ∼ 3.15 kg·m−2·h−1 under one sun illumination. Solar steam generation has gained significant attention as a promising method for clean and sustainable water purification and desalination. The spectral absorption performance of the photothermal conversion material directly affects its thermal conversion efficiency. This research investigates the enhanced near-infrared absorption of Cs 0.32 WO 3 nanoparticles for efficient interfacial solar steam generation. In this study, Cs 0.32 WO 3 nanoparticles were synthesized using a simple co-precipitation and heat treatment method. The synthetic nanoparticles were then incorporated into a porous membrane to create a photothermal conversion material for solar steam generation and their near-infrared absorption properties were characterized. The experimental results demonstrated that the Cs 0.32 WO 3 nanoparticles effectively converted solar energy into heat, resulting in efficient interfacial steam generation. The membrane showed a high evaporation rate of of ∼ 3.15 kg·m−2·h−1 under one sun illumination. The findings of this study provide valuable insights into the design and development of efficient solar steam generation systems using near-infrared absorption nanomaterials. [ABSTRACT FROM AUTHOR]

Solar-driven water generation especially interfacial solar steam generation (ISSG) technology holds the potential of revolutionizing fresh water production and resolving energy crises. With ISSG system operating at the air-liquid interface, it enables localized solar-to-heat conversion and restrictive thermal energy losses. Advances in optimized material design in parallel to engineered evaporator construction, and adjustable energy management now allow ISSG to obtain excellent light absorption, evaporation efficiency and outstanding heat regulation for pursuing highly efficient low-energy-consume water production. The parallel development of enthalpy reduction technology, as an effective avenue towards high-performance ISSG system, was imperative and has gained wide recognition. In this review, the conceptual designs and fundamental mechanism of ISSG technology pertaining to the current progress in materials design, steamer construction and energy regulation applications will be presented. And this article will highlight recent progress on how to reduce evaporation enthalpy involving the enthalpy reduction principle, the implementation and measurements of their influence on ISSG technology. This article aims to provide a comprehensive review on reducing enthalpy strategies in ISSG system and suggest directions to further improve the overall efficiency through the judicious choice of materials, while synchronously capitalizing the increase of intermediate water, establishment of microstructures, regulation of the surface wetting state and water activation of electricity to realize concurrent high evaporation rate. [Display omitted] • Presenting the conceptual designs and fundamental mechanism of interfacial solar steam generation (ISSG) technology. • Highlighting the principle, implementation and measurements on how to reduce evaporation enthalpy on ISSG technology. • Reviewing the reducing enthalpy strategies in ISSG system and suggest directions to improve the overall efficiency. [ABSTRACT FROM AUTHOR]

Biomass-based materials usually evolve well-developed and unique structures for the transportation of water and nutrition to their pivotal organs. These natural intricate designs allow fascinating properties when harnessed in specific real-world application. Herein, we demonstrate that 3D carbonized corncob (C-corncob) harmoniously coordinates light absorption, water supply, vapor escape, and efficiently utilizes the environmental energy to enhance the performance of the steam generation device due to its multilevel inside and side surface structures. The interfacial solar steam generation based on C-corncob achieves as high as 4.16 kg m−2 h−1 evaporation rate under 1.0 sun illumination and readily overcomes the salt deposition problem. These findings not only demonstrate the competence of the recrement corncob as the lost cost material for interfacial solar steam generation, but also provide inspiration for the creation of solar steam generation devices with the new concept. The carbonized corncob based solar vapor steam generator were successfully prepared through facile and simple carbonization process, along with deeply investigating the performance of the interfacial solar-driven steam generation of these carbon-based devices. The interfacial solar steam generation based on C-corncob achieves a higher evaporation rate under 1.0 sun illumination by Environmental Energy, more importantly, the devices overcome the limitation of sunshine duration by efficiently utilizing external energy as a full-time vapor generator. [Display omitted] • A high performance steam generator based on carbonized corncob has been developed. • The biomass based steam generator possesses unique hierarchical porous structures. • The 3D carbon steam generator allows environmental energy utilization. • The biomass based steam generator exhibits excellent salt resistence and long-term stability in sea water. [ABSTRACT FROM AUTHOR]

In this work, for the first time, spent coffee grounds (SCGs) were utilized for photothermal conversion. SCG-coated filter paper was obtained by a facile vacuum filtration method, then a floatable interfacial solar steam generation (ISSG) device was fabricated by wrapping expandable polyethylene (EPE) foam with the SCG-coated filter paper. The photothermal property and solar-driven evaporation performance of the ISSG device were investigated. Experimental results showed that there were graphitic π electrons in SCG and it exhibited light adsorption above 50% within the wavelength of 200–720 nm. The surface temperature of the ISSG device can finally achieve 63.2 °C under 0.25 sun irradiation, and the solar steam yield was enhanced by 0.56 times with the assistance of the floating ISSG device on bulk water surface. This study can provide a feasible technical support for the effective utilization of SCG and water treatment via low-cost ISSG process. [ABSTRACT FROM AUTHOR]

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., (© 2024 The Authors. Advanced Materials published by Wiley‐VCH GmbH.)

Photothermal Ni-doped LaFeO 3 (NLFO) (LaFe 1-x Ni x O 3 , x = 0, 0.2, 0.3, 0.4, and 0.5) microspheres composed of nanoparticles synthesized by hydrothermal method are utilized for interfacial solar steam generation (ISSG) of salty and contaminated water. The orthorhombic (pnma) to rhombohedral (R 3 c ¯) phase transition of LaFeO 3 (LFO) at morphotropic phase boundary (MPB) flattens the free energy profile, and high absorbance in the 800–2000 nm Vis-NIR region arises due to the creation of intra-band gap states are accountable for superior activity towards the ISSG for desalination. The La, Ni, and Fe possess the oxidation states of 3+, 2+, and 3+/4+, respectively, showing successful doping of Ni2+ at the Fe3+ sites that produce lattice distortion at La/FeO 6 octahedra. LaFe 0.5 Ni 0.5 O 3 (NLFO5) sample exhibits surface temperature of 50.4 °C due to heat localization and produces evaporation flux of 2.89 kg/m2h under IR illumination at the air-water interface. Importantly, NLFO5 loaded cellulose paper shows good repeatability and cyclic stability for 10 consecutive cycles under IR illumination and equivalent evaporation flux of 2.4 kg/m2h under direct sunlight illumination. Moreover, 3.5 wt% saline water shows a drastic decrement in ion concentration after ISSG, as confirmed by atomic absorption spectroscopy. Furthermore, NLFO5 possesses good evaporation flux of 2.27 and 2.20 kg/m2h for water contaminated with RhB and MB organic dye. Our results propose the NLFO as distinguished photothermal material for ISSG application and wastewater purification by means of evaporation. Intra-band state creation in Ni-doped LaFeO 3 (NLFO) due to the presence of La3+, Ni2+, Fe3+/Fe4+, and O2− delivered excellent desalination and dye removal, and presented as one of the finest photothermal materials for real-time applications in interfacial solar steam generation and photodegradation of organic dyes from contaminated wastewater. [Display omitted] • High absorbance due to creation of intra-band gap states provided superior activity towards the SSG. • ~50.4 °C rise in surface temperature for NLFO5. • Real-time desalination of 3.5 wt% salt water. • RhB and MB dye separation under direct sunlight. • Drastic decrement in salt concentration after SSG as confirmed from AAS. [ABSTRACT FROM AUTHOR]

[Display omitted] • The porous carbon polyhedron is obtained from controlled carbonization of Ba-BDC. • PCP-based evaporator and device realize freshwater production and energy harvesting. • Evaporator shows the evaporation rate of 2.74 kg m-2h−1 with efficiency of 98.2 % • Device shows the open-circuit voltage of 210 mV with the good cycling stability. The integration of interfacial solar steam generation with water evaporation-driven electricity generation is regarded as one of the most hopeful strategies for addressing global energy and freshwater crises. However, constructing low-cost, multi-functional porous carbon materials-based devices for freshwater-electricity co-generation remains challenging. Herein, we report the preparation of porous carbon polyhedron (PCP) by the controllable carbonization of barium-based metal–organic frameworks produced by the two-step ball milling of waste polyester bottles, and subsequently fabricate PCP-based solar evaporators and energy harvesting devices, capable of freshwater production and electrical energy generation all day. The as-prepared PCP evaporator owns good hydrophilicity, sunlight absorption, excellent photothermal conversion capability as well as low evaporation enthalpy. Under 1 Sun irradiation, it exhibits the evaporation flux of 2.74 kg m-2h−1 as well as the conversion efficiency of 98.2 %. Importantly, the PCP evaporator-based energy generation device realizes the open-circuit voltage of 212 mV, along with the good cycling stability. The well-developed pore channels, large specific surface area, and abundant functional groups are proved to be key parameters for electricity generation. Furthermore, the density functional theory model result unravels that the as-formed potential field inhibits OH–, thus creating a potential difference between upper and lower terminals. This research outlines a "Win-Win" strategy aimed at achieving environmentally friendly, high-value repurposing of waste polyester. Additionally, it aims to develop sophisticated co-generation devices for producing both freshwater and electricity. [ABSTRACT FROM AUTHOR]

The controllable carbonization of waste plastics into functional carbon nanomaterials towards environmental remediation, energy conversion and storage has received widespread attention. However, there are few studies on the carbonization of poly(lactic acid) (PLA) into porous carbon. Herein, the controlled carbonization of PLA into crumped carbon nanosheet (CCN) is reported. Firstly, recycled PLA bags are converted into magnesium-based metal-organic framework (Mg-MOF) through the combined strategy of mechanochemical milling and solution mixing, and then Mg-MOF is transformed into CCN through the metal-organic framework (MOF)-assisted carbonization strategy. CCN exhibits merits of abundant nanopores and oxygen-containing groups. As a result, the CCN-derived evaporator holds good light absorptivity, low evaporation enthalpy, and good light-to-thermal conversion ability. Furthermore, the CCN-derived solar evaporator achieves a high evaporation rate (2.70 kg m−2 h−1) at 1 kW m−2 irradiation, along with good long-term stability, which surpasses many recent advanced solar evaporators. Noteworthy, when wastewater, lake water, seawater, tetracycline solution, and dye-polluted water are used, the CCN-based evaporator remains high performance in freshwater production. Importantly, an outdoor CCN-based device is constructed, which realizes the freshwater production of 6.3 kg m−2. The collected freshwater can cultivate well mung bean sprouts under natural condition. This work not only provides a new "turning-waste-into-treasure" method for the recycling of waste PLA, but also offers a novel strategy for the preparation of low-cost, functional carbon materials for diverse applications. [Display omitted] • Mg-MOF with daisy-like morphology is prepared from waste PLA bags in a green manner. • Carbon nanosheet with a thickness of 2.5 nm is obtained by carbonization of Mg-MOF. • The carbon nanosheet-based evaporator effectively realizes freshwater production. • Evaporator shows the evaporation rate of 2.71 kg m−2 h−1 with efficiency of 98.6%. • This work provides a new "turning-waste-into-treasure" strategy for PLA recycling. [ABSTRACT FROM AUTHOR]

Interfacial solar steam generation (ISSG) is a sustainable and promising technology. Solar energy is used to desalinate seawater and purify industrial wastewater. Solar absorbers based on carbonized biowaste have received increasing attention because they are biocompatible, carbon-rich, hydrophilic, have low thermal conductivity, and exhibit excellent solar absorption. We fabricated a three-dimensional (3D) photothermal material based on carbonized orange peel (COP) for ISSG. The microscopic pores of COP ensured excellent thermal insulation, and the upward-concave shape enhanced light absorption and the self-floating capacity. COP exhibited an evaporation rate of 1.86 kg m−2 h−1 and energy efficiency of 87.90 % under 1 sun irradiation. Additionally, the salt rejection rate was 99.99 % during desalination, and the dye removal rate was 100 % during water purification. Our solar evaporator is thus a low-cost and efficient means of ISSG, and it shows that biowastes can serve as effective photothermal materials. 3D self-floating upward concave-shaped COP has been designed by using a freeze-drying method followed by carbonization in the inert atmosphere. 3D self-floating upward concave-shaped evaporator exhibited extremely efficient water evaporation capability due to its unique shape providing large surface area, excellent hydrophilicity, and good solar-to-heat conversion ability. [Display omitted] • A 3D self-floating concave shaped biowaste orange peel-derived evaporator was designed. • The absorber possessed large surface area, excellent hydrophilicity, and good solar-to-heat conversion ability. • COP evaporator exhibited an evaporation rate of 1.86 kg m−2 h−1 and an efficiency of 87.90 % under 1 sun. • The unique design demonstrated 99.99 % salt rejection for desalination and 100 % dye removal for water purification. [ABSTRACT FROM AUTHOR]

In recent years, interfacial solar steam generation (ISSG) has been considered a potential solution to the current energy crisis and lack of freshwater. In ISSG, a novel solar interfacial evaporator is allowed to float on the bulk water. It has the ability to supply adequate water to the evaporative surface, suppress heat loss and improve light-to-vapour conversion efficiency. Since 2014, innovative photothermal materials as well as different types of advanced structural designed interfacial evaporators have been introduced in ISSG. This rapid development of evaporators has resulted in the evaporation efficiency of 100 % with least energy consumption. In this review, ultrahigh evaporation performance of ISSG with different types of solar evaporators (foam, wood, hydrogel, aerogel, membrane, 3D printing, paper and plant-based evaporators), fabrication process and vapour formation mechanisms are explored. After examining the latest technologies and advancements in research, potential methods to enhance the efficiency of ISSG under different levels of solar irradiation are described. Further, the challenges such as salt rejection technique, minimizing heat loss, water transport technique and condensation process are reviewed. Subsequently, the applications of ISSG in dye removal, water desalination, microorganism removal and power generation are explored. Eventually, the summary and outlook for improving this technology for real-world applications are summarized. [Display omitted] • We summarize the recent development of different types of solar evaporators. • Fabrication and vapour formation processes of different evaporators are reviewed. • Salt removal and other potential applications of ISSG are discussed. • We provide future suggestion to improve the ISSG performance. [ABSTRACT FROM AUTHOR]

Addressing the challenge of water scarcity effectively involves employing a scalable, affordable, maintainable, porous, and efficient interfacial surface solar steam generator (ISSG). Herein, we explore that the efficacy of Bi-doped VO2 (Bi:VO2) as an efficient photothermal material coated on poplar wood is investigated within the ISSG of seawater. The integration enhances the photothermal conversion efficiency of VO2, primarily via the surface plasmon resonance (SPR) effect. The optimal performance was achieved for Bi:VO2 with the concentration of 2 g L−1. This configuration achieved a remarkably high evaporation flux of 3.4 kg m−2 h−1 and was achieved under the power density of 3 sun (1 sun = 1 kW m−2), surpassing the evaporation rate of seawater alone by sixfold. Significantly, this photoabsorber reduced Na+ concentration in seawater from 1200 to 100 mg L−1. The high ISSG performance of the Bi:VO2 photoabsorber in the ISSG can be attributed to several factors, notably the absorption of visible and near-infrared light, the SPR effect induced by Bi, and the low thermal conductivity and porous structure of wood as a substrate. Furthermore, the Bi:VO2 photoabsorber demonstrates remarkable stability, maintaining consistent efficiency even after 10 cycles. [ABSTRACT FROM AUTHOR]

In recent years, interfacial solar steam generation (ISSG) has attracted considerable interest as a means of producing fresh water from various water sources. And photothermal materials play a crucial role in the ISSG system, significantly impacting the efficiency of water evaporation. Among the numerous photothermal materials for ISSG, natural photothermal materials have attracted extensive attention due to their eco-friendliness, renewability, and cost-effectiveness. These materials possess the essential attributes required for efficient solar interfacial evaporators, including hygroscopicity, solar absorption, and thermal conversion, making them well-suited for the large-scale development of high-performance interfacial evaporators. This review summarizes recent advances in the application of natural materials in the ISSG system, lists strategies to enhance the photothermal properties of natural materials, analyzes the design advantages and functionalities of natural materials in thermal management and water transport (major influencing factors of ISSG system's evaporation efficiency), and aims to provide references for research on natural materials in the field of ISSG system. [Display omitted] • Recent advances in the application of natural materials in ISSG systems are Reviewed. • Modification strategies for natural materials and their enhancement mechanisms are Elucidated. • Offering insights for researchers engaged in the exploration of natural materials based ISSG system. • Summarizing and prospecting the research prospects of natural materials for ISSG. [ABSTRACT FROM AUTHOR]

An interfacial solar steam generation evaporator for seawater desalination has attracted extensive interest in recent years. Nevertheless, challenges still remain in relatively low evaporation rate, unsatisfactory energy conversion efficiency, and salt accumulation. Herein, we have demonstrated a biomimetic bilayer composite aerogel consisting of bottom hydrophilic and vertically aligned EVOH channels and an upper hydrophobic conical Fe 3 O 4 array. Thanks to the design merits, the 3D Fe 3 O 4 /V-EVOH evaporator exhibits a high evaporation rate of ∼2.446 kg m -2 h -1 and an impressive solar energy conversion efficiency of ∼165.5% under 1 sun illumination, which is superior to those of state-of-the-art evaporators reported so far. Moreover, the asymmetrical wettability not only allows the evaporator to self-float on the water but also facilitates the salt ion diffusion in the channels; thus, the evaporator shows no salt crystals on its surface and only a 6% decrease in evaporation performance even after the salt concentration increases from 0 to 10.0 wt %.

[Display omitted] • The 3D aerogel of chitosan and GnP was synthesized via templating and freeze-drying. • Changing solution concentration adjusts gel density, influencing fluid transport. • Chitosan/GnP aerogel leverages both high and low density benefits. • Analyzing evaporation features via aerogel aspect ratio and wind speed control. • Laminated chitosan/GnP aerogel maintains water-ion balance, preventing salt buildup. Interfacial solar steam generation (ISSG) is a novel approach to freshwater generation. In practical utilization of new ISSG technology, achieving high evaporation rate is a crucial step. A three-dimensional (3D) solar absorber can increase the exposed surface area and enhance the escape of water molecules to the surrounding environment. However, vigorous evaporation induces to dry out the evaporator quickly, leading to damage its structure or decreased efficiency. In this context, a transversely laminated aerogel-based 3D evaporator is proposed. For this, chitosan/graphene nanoplatelets (CG) are incorporated to create laminated CG (LCG) aerogels having two different densities in a single structure. The results demonstrate that LCG aerogels exhibit rapid water-rise ability and excellent solar absorption characteristics. The laminated structure enhances mechanical strength and maintains balanced water and ion gradients sustainably, inducing a wettable and evaporation-enhanced condition. With these advantages, the evaporation rate of LCG aerogels with aspect ratio (AR) of 7 achieves 2.17 kg m−2h−1. In addition, evaporation experiments were conducted by applying precisely-controlled wind in a wind tunnel to the 3D evaporator. At a wind speed of 6 m s−1, the proposed evaporator achieves a maximum evaporation rate of 5.98 kg m−2h−1. Aerogel with a single density is better suited for situations where only solar radiation is present, while the LCG aerogel, which can utilize the features of two densities at the same time, is more effective in windy conditions. The evaporation efficiency is over 73 % for seawater and 20 wt% high-concentration NaCl solution, showing excellent durability with salt-resistance. The proposed aerogel-based evaporators would be utilized as a sustainable seawater desalination technology for environmentally friendly freshwater production. [ABSTRACT FROM AUTHOR]

Integrating interfacial solar steam generation with advanced oxidation process (AOP) is regarded as a promising strategy for addressing energy and environmental issues. However, developing dual-functional evaporators well-integrated with synergistic photothermal-AOP catalysis properties remains challenging. Herein, we synthesize cobalt-based metal-organic framework (Co-CAT) and prepare dual-functional Co-CAT evaporators. Co-CAT is endowed with "all-in-one" functions, i.e., high specific surface area, effective light absorption, and high catalytic activity. Co-CAT exhibits superior sunlight absorption and photo-to-thermal conversion property. The large specific surface area and abundant micropore of Co-CAT facilitate water permeation and evaporation enthalpy reduction. COMSOL Multiphysics and density functional theory calculation results prove that Co2+ sites in Co-CAT and heat localization promote peroxymonosulfate activation. Consequently, it not only exhibits a high-water evaporation rate of 2.2 kg m−2 h−1, outperforming the-state-of-art evaporators, but also presents the notable tetracycline degradation efficiency (91.1 %). This work proposes an ingenious way to deal with freshwater shortage and water pollution. [Display omitted] • Co-CAT with "all-in-one" functions is prepared by a facile hydrothermal method. • Co-CAT evaporator realizes wastewater purification and freshwater production. • Co-CAT owns good photothermal conversion ability and rises AOP catalysis efficiency. • Localized solar heat and rich open Co sites of Co-CAT promote the activation of PMS. • Evaporator shows an evaporation rate of 2.2 kg m−2 h−1 with TC removal of 91.1 %. [ABSTRACT FROM AUTHOR]

Water desalination through interfacial solar steam generation (ISSG) has been introduced as a sustainable technology to overcome the potable water supplying challenges. In the floating devices employed for ISSG, three main processes of sun-photons absorption, heat generation and management, and water transferring are integrated to produce steam. Inorganic scaling in these devices is considered as one of the main challenges they face, causing the loss of performance during the operation, emphasizing the importance of salt-resistant ability. This work focuses on the problem of the salt-precipitation in the ISSG systems and the strategies that have been employed for overcoming this challenge. In this regard, the used strategies are categorized into four groups including dissolving back precipitated salt via diffusion, double-layer Janus structure, salt ion repulsion, and localizing salt crystals on borders. To obtain insight on a realistic path towards durable and commercially viable ISSG devices, it shows how the materials especially polymers and structures have been engineered to make the device salt-resistant, providing its performance stability. Finally, this work focuses on the future perspectives of the polymer-based ISSG devices regarding their salt-resistant feature and practical applications. Schematic diagram of the available salt removal technologies using the unique properties of polymers [1-6]. [Display omitted] • Structure, mechanisms, challenges, and current status of ISSG systems are reviewed. • Inorganic scaling in ISSG systems is focused on mainly in polymer-based devices. • Salt-rejection mechanisms are categorized in four groups and studied in detail. • Suggestions regarding needed improvements and future direction are presented. [ABSTRACT FROM AUTHOR]

Interfacial solar steam generation (ISSG) is a potential technology to relieve the freshwater shortage. However, developing a cost-effective method to design photo-absorbers with steady desalination performance remains a significant challenge. A Fe 3 O 4 -polyvinyl alcohol sponge photo-absorber (Fe-PAS) was made by employing sodium alginate and CaCl 2 in a simple chemical crosslinking process. Because the porous structure of the polyvinyl alcohol sponge (which traps sunlight) and the narrow bandgap of the Fe 3 O 4 (which captures sunlight) work together, the light absorption of wet Fe-PAS can reach 96.54 %, making water evaporate at a rate of 1.44 kg m−2 h−1. With the help of a sufficient water supply from the polyester fiber pillar (PFP), the Fe-PAS photo-absorber shows a steady evaporation rate of about 1.40 kg m−2 h−1 under 1-solar intensity during desalination. The 240 h (30 days, with 8 h of operation per day) of indoor desalination experiments prove that Fe-PAS is durable and has a steady evaporation performance. Outdoor desalination experiments demonstrate that Fe-PAS can extract freshwater from salt water. The Fe-PAS photo-absorber offers a substantial possibility in mitigating freshwater shortages. • The porous structural PAS and narrow bandgap Fe 3 O 4 achieve high light absorption. • CaCl 2 and SA can improve the stability of Fe-PAS in seawater. • Adequate water supply allows Fe-PAS to attain a steady desalination performance with an evaporation rate of around 1.40 kg m−2 h−1. • Fe-PAS is durable and cost-effective. [ABSTRACT FROM AUTHOR]

Interfacial solar-driven steam generation (ISSG) applied to desalination is considered as a promising technology to solve freshwater crisis. However, challenges remain in the high cost of raw materials, complex manufacturing and the inability to scale. In this paper, a novel interfacial solar-driven evaporator based on ultra-black carbon black-coated pomelo peel (UB-PP) is proposed for high-efficiency desalination, the synergistic effect of natural PP with unique structural properties and the surface high absorption rate photothermal material endows the UB-PP evaporator with high evaporation efficiency, in which the unique multi-curvature gradient and interconnected porous structure is the key to achieving superior solar water evaporation. Under the local high photothermal conversion heat on the surface, the ubiquitous structure provides timely self-water supply, fast water transport, water activation and multi-channel steam release, resulting in the UB-PP evaporator with excellent water evaporation rate of 1.81 kg·m−2·h−1 under 1 sun. Benefiting from the "Turning waste into treasure" strategy and simple preparation method, the overall material cost is as low as $2.7 m−2, enabling the practical large-scale application of UB-PP in desalination and providing a cost-effective management strategy for biowaste. [Display omitted] [ABSTRACT FROM AUTHOR]