Nitrogen-doped microporous graphite-enhanced copper plasmonic effect for solar evaporation

Water scarcity is a global challenge,and solar evaporation technology offers a promising and eco-friendly solution for freshwater production.Photothermal conversion materials(PCMs)are crucial for solar evaporation.Improving photothermal conversion efficiency and reducing water evaporation enthalpy are the two key strategies for the designing of PCMs.The desired PCMs that combine both of these properties remain a challenging task,even with the latest advancements in the field.Herein,we developed copper nanoparticles(NPs)with different conjugated nitrogen-doped microporous carbon coatings(Cu@C–N)as PCMs.The microporous carbon enveloping layer provides a highly efficient pathway for water transport and a nanoconfined environment that protects Cu NPs and facilitates the evaporation of water clusters,reducing the enthalpy of water evaporation.Meanwhile,the conjugated nitrogen nodes form strong metal-organic coordination bonds with the surface of copper NPs,acting as an energy bridge to achieve rapid energy transfer and provide high solar-to-vapor conversion efficiency.The Cu@C–N exhibited up to 89.4%solar-to-vapor conversion efficiency and an evaporation rate of 1.94 kgm^(−2) h^(−1) under one sun irradiation,outperforming conventional PCMs,including carbon-based materials and semiconductor materials.These findings offer an efficient design scheme for high-performance PCMs essential for solar evaporators to address global water scarcity.

Ionization Engineering of Hydrogels Enables Highly Efficient Salt‑Impeded Solar Evaporation and Night‑Time Electricity Harvesting

Interfacial solar evaporation holds immense potential for brine desalination with low carbon footprints and high energy utilization.Hydrogels,as a tunable material platform from the molecular level to the macroscopic scale,have been considered the most promising candidate for solar evaporation.However,the simultaneous achievement of high evaporation efficiency and satisfactory tolerance to salt ions in brine remains a challenging scientific bottleneck,restricting the widespread application.Herein,we report ionization engineering,which endows polymer chains of hydrogels with electronegativity for impeding salt ions and activating water molecules,fundamentally overcoming the hydrogel salt-impeded challenge and dramatically expediting water evaporating in brine.The sodium dodecyl benzene sulfonate-modified carbon black is chosen as the solar absorbers.The hydrogel reaches a ground-breaking evaporation rate of 2.9 kg m−2 h−1 in 20 wt%brine with 95.6%efficiency under one sun irradiation,surpassing most of the reported literature.More notably,such a hydrogel-based evaporator enables extracting clean water from oversaturated salt solutions and maintains durability under different high-strength deformation or a 15-day continuous operation.Meantime,on the basis of the cation selectivity induced by the electronegativity,we first propose an all-day system that evaporates during the day and generates salinity-gradient electricity using waste-evaporated brine at night,anticipating pioneer a new opportunity for all-day resource-generating systems in fields of freshwater and electricity.

A hierarchical salt-rejection strategy for sustainable and high-efficiency solar-driven desalination

Solar steam generation(SSG)is widely regarded as one of the most sustainable technologies for seawater desalination.However,salt fouling severely compromises the evaporation performance and lifetime of evaporators,limiting their practical applications.Herein,we propose a hierarchical salt-rejection(HSR)strategy to prevent salt precipitation during long-term evaporation while maintaining a rapid evaporation rate,even in high-salinity brine.The salt diffusion process is segmented into three steps—insulation,branching diffusion,and arterial transport—that significantly enhance the salt-resistance properties of the evaporator.Moreover,the HSR strategy overcomes the tradeoff between salt resistance and evaporation rate.Consequently,a high evaporation rate of 2.84 kg m^(-2) h^(-1),stable evaporation for 7 days cyclic tests in 20 wt%NaCl solution,and continuous operation for 170 h in natural seawater under 1 sun illumination were achieved.Compared with control evaporators,the HSR evaporator exhibited a>54%enhancement in total water evaporation mass during 24 h continuous evaporation in 20 wt%salt water.Furthermore,a water collection device equipped with the HSR evaporator realized a high water purification rate(1.1 kg m^(-2) h^(-1)),highlighting its potential for agricultural applications.

Designing high-efficiency light-to-thermal conversion materials for solar desalination and photothermal catalysis

Light-to-thermal conversion materials(LTCMs)have been of great interest to researchers due to their impressive energy conversion capacity and wide range of applications in biomedical,desalination,and synergistic catalysis.Given the limited advances in existing materials(metals,semiconductors,π-conjugates),researchers generally adopt the method of constructing complex systems and hybrid structures to optimize performance and achieve multifunctional integration.However,the development of LTCMs is still in its infancy as the physical mechanism of light-to-thermal conversion is unclear.In this review,we proposed design strategies for efficient LTCMs by analyzing the physical process of light-tothermal conversion.First,we analyze the nature of light absorption and heat generation to reveal the physical processes of light-to-thermal conversion.Then,we explain the light-to-thermal conversion mechanisms of metallic,semiconducting andπ-conjugated LCTMs,and propose new material design strategies and performance improvement methods.Finally,we summarize the challenges and prospects of LTCMs in emerging applications such as solar water evaporation and photothermal catalysis.

Boosting extraction of Pb in contaminated soil via interfacial solar evaporation of multifunctional sponge

Interfacial solar water evaporation is a reliable way to accelerate water evaporation and contaminant remediation.Embracing the recent advance in photothermal technology,a functional sponge was prepared by coating a sodium alginate(SA)impregnated sponge with a surface layer of reduced graphene oxide(rGO)to act as a photothermal conversion medium and then subsequently evaluated for its ability to enhance Pb extraction from contaminated soil driven by interfacial solar evaporation.The SA loaded sponge had a Pb adsorption capacity of 107.4 mg g^(-1).Coating the top surface of the SA sponge with rGO increased water evaporation performance to 1.81 kg m^(-2)h^(-1)in soil media under one sun illumination and with a wind velocity of 2 m s^(-1).Over 12 continuous days of indoor evaporation testing,the Pb extraction efficiency was increased by 22.0%under 1 sun illumination relative to that observed without illumination.Subsequently,Pb extraction was further improved by 48.9%under outdoor evaporation conditions compared to indoor conditions.Overall,this initial work shows the significant potential of interfacial solar evaporation technologies for Pb contaminated soil remediation,which should also be applicable to a variety of other environmental contaminants.

Micro–Nano Water Film Enabled High‑Performance Interfacial Solar Evaporation

Interfacial solar evaporation holds great promise to address the freshwater shortage.However,most interfacial solar evaporators are always filled with water throughout the evaporation process,thus bringing unavoidable heat loss.Herein,we propose a novel interfacial evaporation structure based on the micro–nano water film,which demonstrates significantly improved evaporation performance,as experimentally verified by polypyrrole-and polydopamine-coated polydimethylsiloxane sponge.The 2D evaporator based on the as-prepared sponge realizes an enhanced evaporation rate of 2.18 kg m^(−2)h^(−1)under 1 sun by fine-tuning the interfacial micro–nano water film.Then,a homemade device with an enhanced condensation function is engineered for outdoor clean water production.Throughout a continuous test for 40 days,this device demonstrates a high water production rate(WPR)of 15.9–19.4 kg kW^(−1)h^(−1)m^(−2).Based on the outdoor outcomes,we further establish a multi-objective model to assess the global WPR.It is predicted that a 1 m^(2)device can produce at most 7.8 kg of clean water per day,which could meet the daily drinking water needs of 3 people.Finally,this technology could greatly alleviate the current water and energy crisis through further large-scale applications.

Fully Superhydrophilic, Self-Floatable, and Multi-Contamination-Resistant Solar Steam Generator Inspired by Seaweed

Highly hydrophilic materials enable rapid water delivery and salt redissolution in solar-driven seawater desalination. However, the lack of independent floatability inhibits heat localization at the air/water interface. In nature, seaweeds with internal gas microvesicles can float near the sea surface to ensure photosynthesis. Here, we have developed a seaweed-inspired, independently floatable, but superhydrophilic (SIFS) solar evaporator. It needs no extra floatation support and can simultaneously achieve continuous water pumping and heat concentration. The evaporator resists salt accumulation, oil pollution, microbial corrosion, and protein adsorption. Densely packed hollow glass microbeads promote intrinsic floatability and heat insulation. Superhydrophilic zwitterionic sulfobetaine hydrogel provides a continuous water supply, redissolves the deposited salt, and endows the SIFS evaporator with excellent anti-fouling properties. With its unprecedented anti-contamination ability, this SIFS evaporator is expected to open a new avenue for designing floatable superhydrophilic materials and solving real-world issues of solar steam generation in complex environmental conditions.

Recyclable Fe_(3)O_(4)@Polydopamine(PDA) nanofluids for highly efficient solar evaporation

Volumetric solar evaporations by using light-absorbing nanoparticles suspended in liquids(nanofluids)as solar absorbers have been widely regarded as one of the promising solutions for clean water production because of its high efficiency and low capital cost compared to traditional solar distillation systems.Nevertheless,previous solar evaporation systems usually required highly concentrated solar irradiation and high capital cost,limiting the practical application on a large scale.Herein,for the first time in this work,polydopamine(PDA)-capped nano Fe_(3)O_(4)(Fe_(3)O_(4)@PDA)nanofluids were used as solar absorbers in a volumetric system for solar evaporation.The introduction of organic PDA to nano Fe_(3)O_(4)highly contributed to the high light-absorbing capacity of over 85%in wide ranges of 200–2400 nm because of the existence of numerous carbon bonds and pi(π)bonds in PDA.As a result,high evaporation efficiency of 69.93%under low irradiation of 1.0 kW m^(-2)was achieved.Compared to other nanofluids,Fe_(3)O_(4)@PDA nanofluids also provided an advantage in high unit evaporation rates.Moreover,Fe_(3)O_(4)@PDA nanofluids showed excellent reusability and recyclability owing to the preassembled nano Fe_(3)O_(4),which significantly reduced the material consumptions.These results demonstrated that the Fe_(3)O_(4)@PDA nanofluids held great promising application in highly efficient solar evaporation.

Fibrous MXene Aerogels with Tunable Pore of Contaminated Seawater

The seawater desalination based on solardriven interfacial evaporation has emerged as a promising technique to alleviate the global crisis on freshwater shortage.However,achieving high desalination performance on actual,oil-contaminated seawater remains a critical challenge,because the transport channels and evaporation interfaces of the current solar evaporators are easily blocked by the oil slicks,resulting in undermined evaporation rate and conversion efficiency.Herein,we propose a facile strategy for fabricating a modularized solar evaporator based on flexible MXene aerogels with arbitrarily tunable,highly ordered cellular/lamellar pore structures for high-efficiency oil interception and desalination.The core design is the creation of 1D fibrous MXenes with sufficiently large aspect ratios,whose superior flexibility and plentiful link forms lay the basis for controllable 3D assembly into more complicated pore structures.The cellular pore structure is responsible for effective contaminants rejection due to the multi-sieving effect achieved by the omnipresent,isotropic wall apertures together with underwater superhydrophobicity,while the lamellar pore structure is favorable for rapid evaporation due to the presence of continuous,large-area evaporation channels.The modularized solar evaporator delivers the best evaporation rate(1.48 kg m-2h-1)and conversion efficiency(92.08%)among all MXene-based desalination materials on oil-contaminated seawater.

The coral-inspired steam evaporator for efficient solar desalination via porous and thermal insulation bionic design

The solar-driven interfacial evaporation(SIE)technology shows great prospects in seawater desalination and sewage treatment,but it is unable to obtain highly efficient and high-quality clean nontoxic water at low cost.Here,a novel biodegradable hydrogel-based solar evaporator(BBH-L)with a bionic coral structure taking Chinese ink as the solar absorber was developed.This evaporator consists of chitosan/polyvinyl alcohol hydrogel and a loofah substrate.The average evaporation rate and efficiency of BBH-L reach 4.37 kg/(m^(2)·h)and 98.2%,respectively,under one sun illumination(1 kW/m^(2)),which are attributed to its excellent thermal localization and water transporting abilities.Meanwhile,high salt resistance enables BBH-L to achieve efficient desalination and purification of other unconventional water.Heavy metal ions in seawater can be effectively removed by chelation and forming hydrogen bonds in hydrogels.This study is anticipated to provide new possibilities to enhance evaporation performance and reduce the costs of water treatment systems.

Hierarchical structures hydrogel evaporator and superhydrophilic water collect device for efficient solar steam evaporation

Efficient light absorption and trapping are of vital importance for the solar water evaporation by hydrogel-based photothermal conversion materials.Conventional strategies are focused on the development of the composition and structure of the hydrogers internal network.In our point of view,the importance of the surface structure of hydrogel has usually been underestimated or ignored.Here inspired by the excellent absorbance and water transportation ability of biological surface structure,the hierarchical structured hydrogel evaporators(HSEs)increased the light absorption,trapping,water transportation and water-air interface,which is the beneficial photothermal conversion and water evaporation.The HSEs showed a rapid evaporation rate of 1.77 kg·m^(-2)·h^(-1)at about 92%energy efficiency under one sun(1 kW·m^(-2)).Furthermore,the superhydrophilic window device was used in this work to collect the condensed water,which avoids the light-blocking caused by the water mist formed by the small droplets and the problem of the droplets stick on the device dropping back to the bulk water.Integrated with the excellent photothermal conversion hydrogel and superhydrophilic window equipment,this work provides efficient evaporation and desalination of hydrogel-based solar evaporators in practical large-scale applications.

Electrochemically prepared coniferous leaf-like nickel black membrane for desalination by solar-thermal energy conversion

The structures of the solar-thermal membranes always influence the performance of light absorption and salt resistance in desalination.Inspired by the hierarchical structure of the coniferous leaves with excellent sunlight absorption in frigid regions,a coniferous leaf-like nickel black(L-Ni)membrane for desalination by solar-thermal energy conversion was prepared through electroplating method under a constant voltage.The light trapping effect of coniferous leaf-like structure led to the light absorption enhanced to 92%,the evaporation rate improved to 1.38 kg·m^(-2)·h^(-1),and the solar-vapor conversion efficiency of L-Ni membrane reaching up to 89.75%under 1 sun irradiation.The stability of the membrane was still excellent after 20 cycles desalination because the coniferous leaf-like structure could enhance the hydrophobicity(water contact angle:152°)of the L-Ni membrane,and it was beneficial to salt resistance.The promising performance of L-Ni membrane with coniferous leaf-like structure provides a possibility to replace the noble metal solar-thermal conversion materials.

Recent strategies for constructing efficient interfacial solar evaporation systems

Interfacial solar evaporation(ISE)is a promising technology to relieve worldwide freshwater shortages owing to its high energy conversion efficiency and environmentally sustainable potential.So far,many innovative materials and evaporators have been proposed and applied in ISE to enable highly controllable and efficient solar-to-thermal energy conversion.With rational design,solar evaporators can achieve excellent energy management for lowering energy loss,harvesting extra energy,and efficiently utilizing energy in the system to improve freshwater production.Beyond that,a strategy of reducing water vaporization enthalpy by introducing molecular engineering for water-state regulation has also been demonstrated as an effective approach to boost ISE.Based on these,this article discusses the energy nexus in two-dimensional(2D)and three-dimensional(3D)evaporators separately and reviews the strategies for design and fabrication of highly efficient ISE systems.The summarized work offers significant perspectives for guiding the future design of ISE systems with efficient energy management,which pave pathways for practical applications.

Facile preparation of multifunctional Cu_(2−x)S/S/rGO composite for all-round residual water remediation during interfacial solar driven water evaporation process

Presently,interfacial solar water evaporation(ISWE)is now injecting new vitality into the field of water remediation.However,during the ISWE process,the nonvolatile pollutants might be concentrated in residual water,and further contaminate the environment.Preparing advanced photothermal materials is in need to get comprehensive purification of various pollutants in residual water.Herein,we report a facile laser thermal method to prepare Cu_(2−x)S/sulfur/reduced graphene oxide(Cu_(2−x)S/S/rGO)nanocomposites for realizing all-round residual water remediation during the ISWE process.The as-prepared Cu2−xS/S/rGO nanocomposites demonstrated excellent photothermal and photocatalytic properties.Through blending with GO nanosheets having excellent adsorption capacity,the synergetic effect of photothermal,photocatalytic,and adsorption properties resulted in highly efficient purification of rhodamine B,bacterial,and heavy metal ions in residual water during the ISWE process.The experimental results also showed that,increasing solar light intensity can promote the residual water remediation,but ultrafast water evaporation under high light intensity may deteriorate the purifying effect.This report may pave a new way to prepare multifunctional materials for water remediation through the ISWE technology.

Directionally tailoring micro-nano hierarchical tower structured Mn_(0.6)Ni_(1.4)Co_(2)O_(y) toward solar interfacial evaporation

Solar interfacial evaporation has been considered as a promising method to alleviate fresh water re-sources shortage.The shortage of freshwater resources requires advanced materials that can accelerate the evaporation of water by the sun.However,the simple structure of photothermal materials are vitally restricted by finite light absorption.Herein,this work presents a strategy for the synthesis of a spinel-type micro-nano hierarchical tower structure solar absorbent(Mn_(0.6)Ni_(1.4)Co_(2)O_(y))with the low forbidden band(=1.56 eV)and high absorption(97.88%).The products show great potential in solar-thermal energy conversion by creating a trapping effect.The prepared solar absorbent and epoxy resin are evenly mixed and then fully immersed in polyurethane(PU)sponge for water evaporation.The hydrophilic and porous Mn_(0.6)Ni_(1.4)Co_(2)O_(y)@PU sponge can quickly deliver water upwards,suppress the heat loss,and concentrate the absorbed heat on the evaporation of water.The products exhibited an excellent evaporation rate of 2.261 kg m^(-2) h^(-1) and an impressive evaporation efficiency of 156%under a single sun exposure.Besides,the samples also can maintain the stability and recycling performance for a long time.These findings show that Mn_(0.6)Ni_(1.4)Co_(2)O_(y) have great application prospects in the solar interfacial evaporation.

Thermal insulation design for efficient and scalable solar water interfacial evaporation and purification

In recent years, solar desalination and water evaporation/purification with various artificial architectures have drawn significant attention. Herein, we introduce a rational design structure for efficient solar water evaporation and purification, focusing on the balance between water transportation and thermal insulation.Natural wood after a simple flame treatment on the surface was utilized as the solar absorber, with a high solar absorbance(~90 %), good hydrophilicity, and excellent heat localization abilities. Besides,a thermal insulator(polystyrene foam) was used to further reduce the thermal loss, and the optimized ratio between the water path and thermal insulator was obtained. A set of floating foam-flamed-wood(F-F-wood) devices were fabricated with a high evaporation rate of 3.92 kgm-2 h-1, exhibiting photothermal purification abilities from seawater and wastewater containing organic dyes and heavy metals. This study sheds light on the rational design of scalable and low-cost devices for solar water evaporation and purification.

Three-dimensional porous photo-thermal fiber felt with salt-resistant property for high efficient solar distillation

The urgent need for fresh water resource is a public issue facing the world.Solar distillation for seawater desalination is a promising freshwater production method.Interfacial solar evaporation systems based on 2 D photo-thermal membranes have been widely studied,but salt pollution is one of the main challenges for solar distillation.In order to solve this problem,a hydrophilic three-dimensional(3 D)porous photo-thermal fiber felt(PFF)was obtained by one-step method,through a simple polydopamine(PDA)coating method with hydrophobic graphite felt as a substrate.The PFF had a good evaporation rate of 1.48 kg m^(-2)h^(-1)and its corresponding light-vapor conversion efficiency reached 87.4%.In addition,the PFF exhibited an excellent salt-resistant ability when applied to photo-thermal evaporation of highsalinity seawater with 10 wt%NaCl,owing to its intrinsic 3 D macroporous structure for the migration circulation of salt ions.The development of the PFF offers a new route for the exploration of salt-re sistant photo-thermal materials and is promising for the practical application of solar distillation.

Light-absorbing copolymers of polyimides as effi

Polyimide(PI),an important engineering polymer with a rigid chemical structure,readily has excellent chemical stability,heat resistance,and electrical insulation but lacks broadband photothermal properties.Herein,we design and synthesize PI copolymers that embrace intrinsic photothermal properties by using two diamine monomers of(Z)-2,3-bis(4-aminophenyl)acrylonitrile(CNDA)and 4,4-diphenyldiamine(NDA)with strong ultraviolet(UV),and near-infrared(NIR)absorption capabilities,respectively.Tuning the molar ratio of the two diamines can modulate UV and NIR light absorption and regulate the intrinsic photothermal properties of PIs.After condensation with pyromellitic dianhydride,the resulting PI-0.5 with a unit molar ratio of CNDA:NDA=1 shows the best photothermal efficiency.PI-0.5 is used to construct 3D steam generators with vertically dried channels by a freeze-drying method.The 3D steam generators show a good water evaporation rate and continuously operate with excellent stability under varying salinity and pH conditions.The synthetic design herein suggests that PI can be molecularly engineered to be intrinsic photothermal materials,expanding the properties and applications of existing PIs.