Hollow Metal-Organic Framework/MXene/Nanocellulose Composite Films for Giga/Terahertz Electromagnetic Shielding and Photothermal Conversion

With the continuous advancement of communication technology,the escalating demand for electromagnetic shielding interference(EMI)materials with multifunctional and wideband EMI performance has become urgent.Controlling the electrical and magnetic components and designing the EMI material structure have attracted extensive interest,but remain a huge challenge.Herein,we reported the alternating electromagnetic structure composite films composed of hollow metal-organic frameworks/layered MXene/nanocellulose(HMN)by alternating vacuum-assisted filtration process.The HMN composite films exhibit excellent EMI shielding effectiveness performance in the GHz frequency(66.8 dB at Kaband)and THz frequency(114.6 dB at 0.1-4.0 THz).Besides,the HMN composite films also exhibit a high reflection loss of 39.7 dB at 0.7 THz with an effective absorption bandwidth up to 2.1 THz.Moreover,HMN composite films show remarkable photothermal conversion performance,which can reach 104.6℃under 2.0 Sun and 235.4℃under 0.8 W cm^(−2),respectively.The unique micro-and macrostructural design structures will absorb more incident electromagnetic waves via interfacial polarization/multiple scattering and produce more heat energy via the local surface plasmon resonance effect.These features make the HMN composite film a promising candidate for advanced EMI devices for future 6G communication and the protection of electronic equipment in cold environments.

Carbon materials for enhanced photothermal conversion:Preparation and applications on steam generation

Photothermal conversion attracted lots of attention in the past years and sorts of materials were explored to enhance photothermal efficiency.In the past years,solar-driven desalination by photothermal conversion was proposed to release the shortage of fresh water and then it was considered much more important to prepare photothermal materials on large scales with high performance and low cost.In this review,we summarized the works on carbon-based photothermal materials in the past years,including the preparation as well as their application in steam generation.From these works,we give an outlook on the difficulties and chances of how to design and prepare carbon-based photothermal materials.

Recentadvancesincarbon‐basedmaterials for solar‐driven interfacial photothermal conversion water evaporation:Assemblies,structures,applications,and prospective

The shortage of fresh water in the world has brought upon a serious crisis to human health and economic development.Solar‐driven interfacial photothermal conversion water evaporation including evaporating seawater,lake water,or river water has been recognized as an environmentally friendly process for obtaining clean water in a low‐cost way.However,water transport is restricted by itself by solar energy absorption capacity's limits,especially for finite evaporation rates and insufficient working life.Therefore,it is important to seek photothermal conversion materials that can efficiently absorb solar energy and reasonably design solar‐driven interfacial photothermal conversion water evaporation devices.This paper reviews the research progress of carbon‐based photothermal conversion materials and the mechanism for solar‐driven interfacial photothermal conversion water evaporation,as well as the summary of the design and development of the devices.Based on the research progress and achievements of photothermal conversion materials and devices in the fields of seawater desalination and photothermal electric energy generation in recent years,the challenges and opportunities faced by carbon‐based photothermal conversion materials and devices are discussed.The prospect of the practical application of solar‐driven interfacial photothermal conversion evaporation technology is foreseen,and theoretical guidance is provided for the further development of this technology.

Practical Realization of a Hybrid Solution for Photovoltaic and Photothermal Conversion

In this paper, an idea and a realization of a hybrid Operational solar system is presented and practically verified discussed on the base of the performance and efficiency results, is confirmed. solution for photovoltaic and photothermal conversion is presented. by the series of experiments. Improvements of the construction are The synergy effect ofphotothermal and photovoltaic part cooperation

Solution-processed D-A-π-A-D radicals for highly efficient photothermal conversion

Organic donor-acceptor semiconductors exhibit great potential in photothermal conversion.However,it is still challenging to achieve pure organic materials with broad absorption comparable with inorganic materials such as graphene.Herein,two D-AD type DPA-BT-O4 and NDI-TPA-O4 and three D-A-π-A-D type Th-O4,Th2-O4,and IDT-O4 were readily prepared via two high-yield steps and simple air oxidization.The stability can be attributed to their multiple resonance structures based on the aromatic nitric acid radical mechanism.Compared with the D-A-D radicals,the conjugation extension of the D-A-π-A-D radicals endows them with a narrowed band gap and broad absorption in powder.Interestingly,the IDT-O4 powder with aggregation-induced radical effect exhibits broad absorption between 300 and 2500 nm,which is comparable with graphene and other inorganic materials.Under irradiation of 0.9 W/cm^(2)(808 nm),the temperature of IDT-O4 powder rises to 250℃within 60 s.The water evaporation conversion efficiency of 94.38%and an evaporation rate of 1.365 kg/m^(2)h^(−1)under one sun illumination were achieved.IDT-O4 stands as one of the most efficient photothermal conversion materials among pure organic materials via a rational design strategy.

Donor-acceptor modulation of coordination polymers for effective photothermal conversion

The targeted construction of donor-acceptor(D-A)materials featuring efficient photothermal(PT)conversion properties has been an attractive but challenging goal.Herein,a new series of coordination polymers(CPs)featuring different PT performances were constructed with flexible linker 1,1′-Ferrocenedicarboxylic acid(FCA)and 2,4,6-tri(pyridin-4-yl)-1,3,5-triazine(TPT)as acceptor and donor molecules including coronene and tetrathiafulvalene(TTF).Based on the flexible configurations of FCA ligand and the directing of donor dependent D-A interactions,the structures of TF-1 to TF-3 featuring distinctive dimension were obtained based on Cd(Ⅱ)ions for investigating the PT property in configurational perspectives.A systematic investigation of the PT properties of the CPs was performed.Notably,TF-3 exhibits the finest PT conversion effect under the irradiation of560 nm laser,while TF-2 shows optimal PT conversion under 808 nm laser irradiation required for biological PT therapy,illustrating the correlation between the structural and component features of the CPs and their PT performances.Furthermore,Zn(Ⅱ)as bio-friendly ion was utilized to construct hypotoxic TF-4 that reveals similar structure to that of TF-2 for potential application.Polydimethylsiloxane(PDMS)patches doped with TF-4 exhibits considerable NIR PT conversion effect under808 nm,represented by the nearly 80℃temperature increased in 120 s for TF-4@PDMS patch(1.2 wt%)under 0.9 W cm^(-2)irradiation,the results of which herein indicate the potential of D-A CPs as versatile platform for the modulation of PT materials.

Waste to treasure:Reutilization of fluid catalytic cracking coke block as photothermal conversion material for water evaporation

This study aims to analyze the coking process and propose an effective method for the reutilization of fluid catalytic cracking(FCC)coke block.Herein,we analyzed the basic characteristics and chemical composition of FCC coke blocks.The results showed that the main components were carbon,oxygen,and aluminum,accounting for 60.8%,26.6%,and 11.5%,respectively.Under the conventional catalytic cracking reaction temperature from 500℃ to 600℃,the formation of the first aromatic hydrocarbon was particularly important for the formation of coke.The condensation of oil-gas-entrained catalyst particles and their heavy components was the physical cause of coking,while the dehydrogenation condensation reaction of oil-gas heavy components was the chemical factor.In addition,the membrane prepared by powdered coke had excellent photothermal conversion ability,which could be heated to more than 110℃ within 360 s under two fixed light intensities.The evaporation rate of photothermal water was 5.89 kg m^(2) h^(−1),which has great industrial application potential.These works provide a novel and effective method of separation membrane for the reutilization of FCC coke blocks.

Organic stoichiometric cocrystals with a subtle balance of charge-transfer degree and molecular stacking towards high-efficiency NIR photothermal conversion

Charge-transfer(CT)stoichiometric cocrystals are promising choice of organic materials for unveiling the structure-property relationship.However,due to the contradiction between large CT degree required for strong NIR absorption and flexible molecular stacking,construction of stoichiomorphism-based cocystals with near-infrared(NIR)photothermal property remains challenging.Herein,the first example of stoichiomorphism-based photothermal cocrystals were accomplished through the adaptive assembly of 3,3,5,5-tetramethylbenzidine(TMB)donor and 1,2,4,5-tetracyanobenzene(TCNB)acceptor.The selective cocrystallization could be controlled by varying the donor-acceptor stoichiometries via a surfactantassisted method,resulting in two cocrystals with 1:1(T1C1)and 1:2(T2C1)stoichiometries.The absorbance intensity of T1C1 at 808 nm was nearly twice that of T2C1,while the photothermal conversion efficiency(PCE)of the former was 60.3%±0.6%,approximately 80%of that for the latter(75.5%±2.6%),which might be caused by the different intermolecular interactions in distinct molecular stacking patterns.Notably,both excellent PCEs of stoichiometric cocrystals were attributed to the nonradiative transition process,including internal conversion and charge dissociation processes,as elucidated by femtosecond transient absorption spectroscopy measurements.Furthermore,T1C1 was used as an NIR heater for preparing agarose-based photothermal hydrogel,showing great potential for light-controlled in-situ gelation.This strategy of balancing the CT degree and molecular packing orientation not only uncovered the relationship between stoichiometric stacking and photothermal property,but also provided an opportunity to develop advanced organic optoelectronic materials.

An efficient photothermal conversion material based on D-A type luminophore for solar-driven desalination

Solar-driven interfacial evaporation is a promising technology for desalination.The photothermal conversion materials are at the core and play a key role in thisfield.Design of photothermal conversion materials based on organic dyes for desalina-tion is still a challenge due to lack of efficient guiding strategy.Herein,a new D(donor)-A(acceptor)type conjugated tetraphenylpyrazine(TPP)luminophore(namely TPP-2IND)was prepared as a photothermal conversion molecule.It exhib-ited a broad absorption spectrum and strongπ–πstacking in the solid state,resulting in efficient sunlight harvesting and boosting nonradiative decay.TPP-2IND powder exhibited high photothermal efficiency upon 660 nm laser irradiation(0.9 W cm-2),and the surface temperature can reach to 200◦C.Then,an interfacial heating system based on TPP-2IND is established successfully.The water evaporation rate and the solar-driven water evaporation efficiency were evaluated up to 1.04 kg m-2 h-1 and 65.8%under 1 sunlight,respectively.Thus,this novel solar-driven heating system shows high potential for desalination and stimulates the development of advanced photothermal conversion materials.

Supra-(carbon nanodots) with a strong visible to near-infrared absorption band and efficient photothermal conversion

A novel concept and approach to engineering carbon nanodots(CNDs)were explored to overcome the limited light absorption of CNDs in low-energy spectral regions.In this work,we constructed a novel type of supra-CND by the assembly of surface charge-confined CNDs through possible electrostatic interactions and hydrogen bonding.The resulting supra-CNDs are the first to feature a strong,well-defined absorption band in the visible to near-infrared(NIR)range and to exhibit effective NIR photothermal conversion performance with high photothermal conversion efficiency in excess of 50%.

Carbon nanocomposites with high photothermal conversion efficiency

Photothermal conversion for water vapor gen- eration is a novel strategy and an efficient way to utilize solar energy, which has great potential for water purification and desalination. In this review, the development of photothermal conversion and the classification of absorbers for solar vapor generation systems are presented, especially in recent devel- opment of carbon nanocomposites （carbon nanotubes and graphene） as solar vapor generation devices. Combined with recent progresses and achievements in this field, we discuss the challenges and opportunities for photothermal conversion based on carbon nanocomposites as well as their promising applications.

Stability,Thermal Conductivity and Photothermal Conversion Performance of Water-Based ZnO Nanofluids

Water-based ZnO nanofluids were prepared via the two-step method,and the influences of dispersant type and mass fraction on the stability and particle size distribution of the nanofluids were investigated.The spectral transmittances of the nanofluids were obtained by a UV-Vis-NIR spectrophotometer.Thermal conductivities of the nanofluids with various mass fractions were measured at different temperatures and a fitted nonlinear correlated equation was established for low-concentration application and compared with existing models.The photothermal conversion performance of the nanofluids was evaluated by theoretical and experimental methods at three optical depths.The results showed that,CTAB as the dispersant provides better physical stability of water-based ZnO nanofluids than SDBS or GA does.Effect of the temperature on the nanofluid thermal conductivity is remarkable with the increase of nanoparticle mass fraction,especially in the range 55°C to 75°C.The maximum thermal conductivity of the studied nanofluids is 0.9488 W/(m·℃)at 75°C,43.61%higher than that of water.The minimum thermal conductivity of the studied nanofluids is 0.6376 W/(m·℃)at 25°C,5.16%higher than that of water.The photothermal conversion performance of the nanofluids is quite good with a maximum average absorption efficiency of 0.47,135%higher than that of water(η=0.2),and the maximum SAR is 527.5 W/g.

Cu nanoparticle-decorated two-dimensional carbon nanosheets with superior photothermal conversion efficiency of 65 % for highly efficient disinfection under near-infrared light

Low photothermal conversion efficiency restricts the antibacterial application of photothermal materials.In this work,two-dimensional carbon nanosheets(2D C)were prepared and decorated with Cu nanoparticles(2D C/Cu)by using a simple soluble salt template method combined with ultrasonic exfoliation.The photothermal conversion efficiency of 2 D C/Cu system can be optimized by changing the content of Cu nanoparticles,where the 2D C/Cu2 showed the best photothermal conversion efficiency(á)of 65.05%under 808 nm near-infrared light irradiation.In addition,the photothermal performance can affect the release behavior of Cu ions.This superior photothermal property combined with released Cu ions can endow this 2D hybrid material with highly efficient antibacterial efficacy of 99.97%±0.01%,99.96%±0.01%,99.97%±0.01%against Escherichia coli,Staphylococcus aureus,and methicillin-resistant Staphylococcus aureus,respectively,because of the synergetic effect of photothermy and ion release.In addition,this 2D hybrid system exhibited good cytocompatibility.Hence,this study provides a novel strategy to enhance the photothermal performance of 2D materials and thus will be beneficial for development of antibiotics-free antibacterial materials with safe and highly efficient bactericidal activity.

Preparation and properties of substrate PVA-GO composite membrane for solar photothermal conversion

Solar thermal desalination(STD)is a promising and sustainable technology for extracting clean water resources.Whereas recent studies to improve STD performance primarily focus on interfacial solar evaporation,a non-traditional bottom heating method was designed in this study.Herein,we prepared the polyvinyl alcohol/graphene oxide(PVA-GO)composite membrane and adhered to the bottom of a beaker using crystallized PVA.The GO was loaded on a non-woven fabric and different concentrations of PVA were compared for their effect on the evaporation efficiency.The results showed that the addition of PVA increased the evaporation rate.The surface characteristic of GO membrane without PVA was a fibrous filamentous structure as observed by SEM,whereby the fibers were clearly visible.When the PVA concentration reached 6%,the non-woven fiber was completely wrapped by PVA.Under the action of a fixed light intensity,the photothermal conversion rates of GO,2%PVA-GO,4%PVA-GO and 6%PVA-GO membrane device could reach 39.93%,42.61%,45.10%and 47.00%,respectively,and the evaporation rates were 0.83,0.88,0.94 and 0.98 kg$m-2$h-1,respectively.In addition,the PVA-GO composite membrane showed an excellent stability,which has significance for industrial application.

Polydopamine-coated metal-organic framework-based composite phase change materials for photothermal conversion and storage

The liquid leakage and weak solar absorption capacity of organic phase change materials(PCMs)seriously hinder the efficient utilization of solar energy and thermal energy storage.To address these issues,we prepared nanoporous metal organic framework(Ni-MOF)for the vacuum infiltration of paraffin wax(PW),followed by the coating of solar-absorbing functional polydopamine(PDA)on the surface of PW@MOF for photothermal conversion and storage.As an efficient photon harvester,PDA coating endows PW@MOF/PDA composite PCMs with excellent photothermal conversion and storage properties due to the robust broadband solar absorption capability in the UV–vis region.Resultantly,our prepared PW@MOF/PDA composite PCMs exhibit a high photothermal conversion and storage efficiency of 91.2%,while that of PW@MOF composite PCMs is only zero.In addition,PW@MOF/PDA composite PCMs also exhibit excellent thermal stability,shape stability,energy storage stability,and photothermal conversion stability.More importantly,this coating strategy is universal by integrating different MOFs and solar absorbers,showing the potential to accelerate the major breakthroughs of high-efficiency MOF-based photothermal composite PCMs in solar energy utilization.

Selective Construction of Borromean Rings and Tweezer-Like Molecular Assembly Featuring Cp^(*)Rh/Ir Clips for Near-Infrared Photothermal Conversion

Making full use of coordination-driven self-assembly strategy,we herein described the selective synthesis of a molecular Borromean rings and two cases of “U”-shaped tweezer-like molecular assemblies in high yield by using bipyridyl ligands based on biphenyl unit and half-sandwich binuclear rhodium(III)/iridium(III) building blocks.The selective synthesis was realized by adjusting the length of dipyridyl arms.The utilization of curved U-shaped bipyridyl ligand L1 led to tweezer-like molecular assemblies.Subsequently,olefinic bonds were introduced to elongate dipyridyl arms obtaining ligand L2.The ligand L2 has two stable conformations,U-shape and Z-shape,which facilitated the formation of different topologies including the tetranuclear macrocycle and Borromean rings with different building blocks in this work.These structures in solid and solution all have been further confirmed by single-crystal X-ray diffraction,NMR analysis,and mass spectrometry.In addition,as an important driving force,π-π stacking interactions not only played a significant role in the stability of structures but also further triggered photothermal conversion in solution.The experimental results demonstrated that compounds 1a and 2 had good NIR photothermal conversion efficiency (11.83% and 17.76%),and further analysis found the photothermal conversion efficiency had a gradual increase in the trend with the π-π stacking interactions increasing.This research expands the application of topological structures in materials science and provides a new idea for the synthesis of novel photothermal conversion materials.

High Thermal Conductivity of Carboxyl-rich Carbon/Polyethylene Glycol Composites for Enhanced Photothermal Conversion and Latent Heat Storage

Polyethylene glycol(PEG)as phase change material(PCM)and carboxyl-rich carbon(RHTC)with different carboxyl content was introduced to prepare RHTC/PEG composites.The composites have high thermal conductivity,photothermal conversion ability,and improved the phase change enthalpy of the system.The microstructure and thermal properties of the samples were analyzed by various characterization methods.RHTC promoted the benign growth of PEG crystallinity(110.0%),influenced the phase change enthalpy of PEG,and improved the latent heat storage capacity of composites.The non-leakage loading of PEG in the composites can be as high as 97 wt%,and the actual phase change enthalpy is 10.7 J/g higher than that of pure PEG,10%higher than the theoretical value.Owing to the heat storage bridge formed between PEG and RHTC,the thermal conductivity of the composites was up to 0.51 W/mK,which was 99.4%higher than that of PEG.Besides,the introduction of environmentally friendly and low-cost RHTC gives the composites excellent photothermal conversion capability,and its photothermal conversion energy storage efficiency is as high as 90.1%.These results prove that the prepared composites are promising potential candidates in the field of thermal storage and thermal management systems.

A smart MXene-copolymeric molecularly imprinted hydrogel with dual-response and photothermal conversion performance for specific recognition of cis-diol compounds

In this work,a novel MXene-copolymeric molecularly imprinted hydrogel(FMMIH)with temperature/pH dual response and photothermal conversion performance for selective recognition of cis-diol compounds is successfully prepared.Functionalized MXene becomes an important part of the hydrogel’s skeleton by participating in the free radical polymerization reaction.Therefore,FMMIH exhibits improved mechanical properties and great photothermal conversion performance.Furthermore,based on the temperature/pH dual response,FMMIH can realize the controllable capture and release of ginsenoside Rb1 with cis diol structures through dual recognitions of functional groups and geometric space.Under the conditions of pH 8.5 and 25℃,the adsorption capacity of FMMIH is 26.3 mg·g^(-1) and the imprinting factor is 16.4,showing a good imprinting effect.It is worth noting that the volume shrinkage caused by photothermal conversion of the hydrogel is conducive to the elution of template molecules and greatly saves the time of desorption(the desorption efficiency is as high as 89.4%under light conditions for 30 min,which is 3.7 times in dark conditions).These excellent properties make it possible to have broad prospects in many fields such as separation of cis-diol compounds,drug delivery systems,and biosensors.

A novel reversible-deactivation radical polymerization strategy via near-infrared light-controlled photothermal conversion dividing wall-type heat exchanger

As an effective means of utilizing light energy,photothermal conversion has excellent application in the field of polymerization.Herein,a dividing wall-type heat exchanger with the aid of photothermal conversion was designed to conduct polymerization under irradiation with near-infrared(NIR)light by utilizing the ketocyanine-type dye solution as the highly efficient activator(>83.2%photothermal conversion efficiency).Various types of reversible-deactivation radical polymerization(RDRP)methods,including reversible addition-fragmentation chain transfer,atom transfer radical polymerization,and bromine-iodine transformation RDRP,are suitable for this strategy.Well-defined polymers with excellent control over molar mass and molar mass dispersity(D<1.28)were thus synthesized within a few hours under NIR(λ_(max)=810 nm,850 nm)irradiation at room temperature.Importantly,in addition to conventional heating methods(such as electrical heating jackets),the designed dividing wall-type heat exchanger via NIR light activation has another unique advantage:it can enhance the polymerization by the synergistic effect of both heating and NIR light irradiation due to the deeper penetration of NIR light.

Self-enhancing photothermal conversion of 2D Weyl semimetal WTe_(2)with topological surface states for efficient solar vapor generation

To improve the performance of solar energy-driven water generation,two-dimensional(2D)photothermal materials requisite to be optimized by some strategies such as alloying,combination of plasmonic and defect modulation.However,the challenges faced in practical utilization are the complex preparation process and insufficient solar spectrum absorption.Herein,we propose a strategy of self-enhancing photothermal performance induced by topological surface states(TSSs).2D WTe_(2)is fabricated on the mixed cellulose ester(MCE)for photothermal device.Compared to the MCE and pure water,WTe_(2)@MCE has an excellent photothermal evaporation rate of 1.09 kg·m^(−2)·h^(−1)upon 1 sun irradiation,promoting 6.1 and 3.1 times,respectively.It can be attributed to the characteristics of 2D Weyl semimetal WTe_(2)with TSSs bringing about high optical absorption capacity,low thermal diffusivity,specific heat capacity,and high carrier density,which are strongly proved by experiments and calculation.More importantly,the contribution of TSSs to the enhancement of optical absorption for efficient solar water generation is revealed by the comparative experiment between 2D WTe_(2)with TSSs and that without TSSs.Furthermore,photothermal conversion mechanism is explored in-depth understanding that the photoexcited electrons recombinate with the holes through nonradiative mode for releasing thermal energy by phonons emission via multiple pathway.This work promotes the application of Weyl semimetal material with TSSs in solar water evaporation.