Photothermal Conversion Performance Research Articles

Plasmonic Copper‐Ruthenium Superstructure for Efficient Photothermal Conversion and Plastic Recycling

AbstractPlasmonic superstructures offer broad prospects in photothermal catalysis, yet their controllable synthesis remains a challenge. Here, a controlled synthesis method for Cu‐Ru plasmonic superstructures via a one‐step polyol reduction process is presented, where Cu nanoparticles serve as the core, while the shell is formed from Ru nanoclusters. Through a comprehensive investigation of the growth mechanism, precise control over the composition and size of the superstructures is achieved. Finite‐difference time‐domain simulations and photothermal conversion experiments demonstrated that the optimized Cu3Ru1 superstructures possess strong light absorption capabilities and efficient photothermal conversion performance. These properties are effectively utilized in the photothermal recycling of waste polyethylene and polyethylene terephthalate, marking a significant advance in employing Cu‐based plasmonic materials for sustainable catalytic technology.

Graphene aerogel with double pore structure for marine oil spill emergency response

Due to its high porosity, large specific surface area, and strong photothermal conversion performance, graphene aerogel has unique advantages in the field of pollution treatment, especially in the field of recovering highly viscous oils. However, for the treatment of highly viscous oils, the high adsorption capacity and high adsorption rate of graphene aerogel often cannot be combined, which is one of the important reasons limiting its development in this field. A double-step templating strategy for graphene aerogels preparation was used in this work, i.e., Pickering emulsion soft templating and unidirectional freeze casting. Specifically, the dense Pickering emulsion droplets can be stabilized in a short period of time, so that they can be cured quickly. After that, graphene aerogels (DGA-0.8-25) with dual pore structure were prepared by unidirectional freeze casting technology to further form aligned pores based on the pores formed by the Pickering emulsion droplet soft template. The dense presence of Pickering emulsion droplets gives DGA-0.8-25 an ultra-high porosity (96.8 %), which can adsorb 184.53 times its own mass of crude oil. Due to the unidirectional pore structure, the adsorption rate of DGA-0.8-25 on crude oil is as high as 8.39 g·g−1·min−1, which realizes dual improvement of the adsorption capacity and rate of graphene aerogel on crude oil and shows a good application prospect in the treatment of high viscosity crude oil. In addition, DGA-0.8-25 has unique advantages in the field of oil–water separation, with a separation efficiency of 99.04 % for water-in-oil emulsions and 97.63 % for oil-in-water emulsions. When repeated used in photothermal adsorption of highly viscous oil, DGA-0.8-25 can still maintain more than 90.61 % of its initial adsorption capacity after ten cycles of use-regeneration. Because of its unique advantages such as high efficiency and low cost, DGA shows promising in its future large-scale use.

Ultrathin, flexible, and high-performance bacterial cellulose/copper nanowires film for broadband electromagnetic interference shielding and photothermal conversion

The swift advancements in wearable electronics, implantable medical devices, fifth-generation mobile communication, unmanned aerial vehicles, and military stealth technology have led to a surge in demand for highly flexible multifunctional films. Consequently, the enhancement of electromagnetic radiation and the requirement for normal operation in extreme environments have posed significant challenges for flexible electromagnetic interference (EMI) shielding films. In this paper, ultra-thin, flexible bacterial cellulose (BC)/copper nanowires (CuNWs) (BCu) films with Janus structure are prepared by the combination of microwave-assisted hydrothermal synthesis and vacuum filtration method, which can be used for broadband EMI shielding and photothermal conversion. BCu films demonstrate exceptional mechanical properties, boasting a tensile strength range from 48.5 to 77.3 MPa, accompanied fracture strain 4.1–5.9 %. When CuNWs mass in Janus film increases to 10 mg, the conductivity of BCu-4 Janus films can reach 4761.90 S cm−1. The ultra-strong EMI shielding effectiveness (SE, above 56.00 dB) is achieved in 6–26.5 GHz for BCu-4 film with an ultra-thin thickness (16 μm). Moreover, the specific EMI SE of BCu-4 is as high as 4294.38 dB mm−1. Furthermore, BCu Janus films exhibit outstanding photothermal conversion performance. A saturation temperature of BCu-4 Janus film reaches as high as 75 °C under irradiation of one sunlight (100 mW cm−2). The facile and collaborative strategy is provided for fabricating ultra-thin, flexible multifunctional Janus films with EMI shielding and photothermal conversion capabilities, addressing EMI problems in modern electronic technology and offering new avenues for applications in various fields.

Multi‐Enzyme Mimetic MoCu Dual‐Atom Nanozyme Triggering Oxidative Stress Cascade Amplification for High‐Efficiency Synergistic Cancer Therapy

AbstractSingle‐atom nanozymes (SAzymes) with ultrahigh atom utilization efficiency have been extensively applied in reactive oxygen species (ROS)‐mediated cancer therapy. However, the high energy barriers of reaction intermediates on single‐atom sites and the overexpressed antioxidants in the tumor microenvironment restrict the amplification of tumor oxidative stress, resulting in unsatisfactory therapeutic efficacy. Herein, we report a multi‐enzyme mimetic MoCu dual‐atom nanozyme (MoCu DAzyme) with various catalytic active sites, which exhibits peroxidase, oxidase, glutathione (GSH) oxidase, and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase mimicking activities. Compared with Mo SAzyme, the introduction of Cu atoms, formation of dual‐atom sites, and synergetic catalytic effects among various active sites enhance substrate adsorption and reduce the energy barrier, thereby endowing MoCu DAzyme with stronger catalytic activities. Benefiting from the above enzyme‐like activities, MoCu DAzyme can not only generate multiple ROS, but also deplete GSH and block its regeneration to trigger the cascade amplification of oxidative stress. Additionally, the strong optical absorption in the near‐infrared II bio‐window endows MoCu DAzyme with remarkable photothermal conversion performance. Consequently, MoCu DAzyme achieves high‐efficiency synergistic cancer treatment incorporating collaborative catalytic therapy and photothermal therapy. This work will advance the therapeutic applications of DAzymes and provide valuable insights for nanocatalytic cancer therapy.

Dual-emission carbon dots-based biosensor for polarity/targeting bimodal recognition and mild photothermal therapy of tumor

It is essential to develop a multifunctional nanoplatform for biosensing, tumor diagnosis and treatment simultaneously. Herein, dual-emission fluorescent carbon dots (HA-CDs) were fabricated via a one-pot solvothermal method using spinach powder as carbon source and hyaluronic acid (HA) as targeting agent. The obtained HA-CDs exhibited outstanding optical properties, good targeted tumor and excellent photothermal conversion performance. Interestingly, HA-CDs can sensitively perceive the changes in polar environments attributed to the inherent ratiometric fluorescence characteristics, and combined with the intrinsic targeting tumor ability achieved tumor cell recognition. More importantly, the HA-CDs possess good photothermal conversion efficiency of 21.2 % to be beneficial for photothermal therapy of tumors. The survival rate of HeLa cells incubated with HA-CDs dramatically decreased to 14 % after 660 nm laser irradiation, revealing the significant tumor inhibition of HA-CDs in vitro. Notably, through individual intraperitoneal and intratumoral injection, it was found that HA-CDs demonstrated a similar tumor suppressed effect on 4T1 tumor-bearing mice exposed to laser irradiation, fully uncovering that HA-CDs can efficiently accumulate at tumor site by intraperitoneal injection. Besides, the histopathological analysis of major organs ex vivo revealed a good biosafety profile. Collectively, this strategy of designed HA-CDs provides a new multifunctional nanoplatform for potential clinical application.

MoS2 Lubricate-Toughened MXene/ANF Composites for Multifunctional Electromagnetic Interference Shielding

HighlightsThe introduction of MoS2 generates a “kill three birds with one stone” effect to the original binary MXene/ANF system: lubrication toughening mechanical performance; reduction in secondary reflection pollution of electromagnetic wave; and improvement in the performance of photothermal conversion.After the introduction of MoS2 into MXene/ANF (60:40), the strain and toughness were increased by 53.5% (from 18.3% to 28.1%) and 61.7% (from 8.9 to 14.5 MJ m−3), respectively. Fortunately, the SER decreases by 22.4%, and the photothermal conversion performance was increased by 22.2% from ~ 45 to ~ 55 °C.

Photothermal Conversion Performance of Fe3O4/ATO Hybrid Nanofluid for Direct Absorption Solar Collector

In order to enhance the efficiency of direct absorption solar collectors, this study carried out an experimental analysis about the optical and photothermal conversion performance of Fe3O4, ATO (Antimony-doped tin oxide), and Fe3O4/ATO nanofluids with a total concentration of 0.1 wt%. According to the results of the experiments, Fe3O4 nanofluid outperforms ATO nanofluid in terms of optical absorption; nevertheless, at wavelengths shorter than 600 nm, it also shows significant scattering reflection. The solar-weighted absorption coefficient of Fe3O4/ATO nanofluid rose from 0.863 (mFe3O4/mTotal = 0.2) to 0.932 (mFe3O4/mTotal = 0.8) when the optical path length increased from 0.01 m to 0.06 m. Moreover, the Fe3O4/ATO hybrid nanofluid achieved a photothermal conversion efficiency of 0.932 when the mass ratio of Fe3O4 to total mass was 0.2, surpassing the efficiencies of 0.892 and 0.898 recorded for 0.1 wt% ATO and Fe3O4 nanofluids, respectively. When present together, the opposing optical characteristics of Fe3O4 and ATO boost photothermal conversion performance, which is anticipated to raise the efficiency of direct absorption solar collectors.

Polymorphic Supramolecular Therapeutic Platforms with Precise Dye/Drug Ratio to Perform Synergistic Chemo-Photo Anti-Tumor Therapy and Long-Term Immune Protection.

Malignant tumor has become one of the hellish killers threatening the health of people around the world, its diagnosis and treatment has become the concerns of public. However, the optimal therapeutic dose, undesired side-effect, and long-term immune activation werekey and bottleneck problems in tumor treatment. Herein, different batches of supramolecular therapeutic platforms, including vesicles, spherical nanoparticles, and cylindrical nanorods, with precise ratios of dye to drug (1:2) and multiple stimulus responsiveness wereconstructed by host-guest complexation between cyanine-camptothecin conjugates (IR780-CPT2) and β-cyclodextrin (β-CD) pendent hydrophilic copolymers. The reduction responsiveness, near-infrared photothermal conversion and singlet oxygen (1O2) generation performances endowed these platforms excellent cancer cells killing effect in both of in vitro cellular experiments and in vivo mice models. More importantly, without affecting the weight of mice, the maturation of dendritic cells, proliferation of T cells, up-regulation of high mobility group protein B1, and reduction of immunosuppressive regulatory T cells weredetected after employing a synergistic chemo-photo therapy, demonstrating the body's immune effect was successfully activated. Thus, during the treatment of primary tumor, the distal tumor was also inhibited. Webelieve this work could provide a distinctive way to fabricate supramolecular theranostic platforms with different morphologies and improve antitumor and antimetastasis capabilities.

Bifunctional Photothermal Evaporator Based on an MXene/Fe-MOF Collaborative Effect toward Efficient Solar Steam Generation and Simultaneous VOC Removal.

Solar-driven interfacial water evaporation has become one of the most promising approaches to effectively harvesting freshwater, yet the fabrication of high-performance and multifunctional solar interfacial evaporators (SIEs) still remains a huge challenge to date. In this study, a multifunctional MXene and Fe-MOF@cellulose acetate/polyvinylpyrrolidone (MXM@CP) SIE was prepared via a facile "electrospinning and suction filtration deposition" coupling strategy. Thanks to the incorporation of MXene, MXM@CP displayed excellent photothermal conversion performance. Together with the fast water transport channel provided by the porous cellulose acetate electrospinning substrate, a remarkable solar-driven water evaporation property was achieved for MXM@CP, showing a higher water evaporation rate of 1.1 kg m-2 h-1 under one sun irradiation. Moreover, the resultant composite film also exhibited excellent Fenton catalytic activity to effectively degrade volatile organic compounds (VOCs) due to the synergistic effect of the MXene and Fe-based MOF (Fe-MOF). Particularly, a relatively higher degradation rate of 82.8% was acquired for the resulting evaporator toward the benzene contaminant. These results provide new insights into the construction of high-performance and multifunctional SIEs toward clean freshwater collection from the VOC-contaminated water system.

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

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

Synergetic integration of photothermal and self-cleaning features in a composite phase change material based on layered double hydroxides and polypyrrole

Composite phase change materials (PCMs) with photothermal functionality play a crucial role in efficiently storing and utilizing solar energy. However, the challenge of effectively removing of contaminants on photothermal conversion coatings has long puzzled researchers. In this study, we propose a novel approach to enhancing both photothermal conversion performance and self-cleaning properties of wood-based composite phase change materials, ultimately facilitating the sustainable and effective utilization of solar energy. The method utilized metal-organic frameworks (MOFs) as a precursor to form rough layered double hydroxides (LDH) on the wood surface through hydrolysis-induced exchange. Subsequently, polypyrrole (PPy) was deposited through vapor phase onto the LDH, and paraffin wax (PW) is utilized as the phase change material to prepare a novel composite phase change material. This modified wood structure facilitates leak-proof PW encapsulation and effective heat storage (167.6 J/g). PPy acts as a proficient photothermal converter and improves the composite material's heat transfer efficiency by establishing thermal conduction pathways, resulting in an 87.4 % enhancement in thermal conductivity compared to pure PW. The rough surface of LDH promotes multiple light reflections and scattering within the material, leading to increased light absorption by the PPy coating and achieving a photothermal conversion efficiency of up to 96.4 %. Furthermore, the high roughness of the LDH layer combined with the low surface energy of PW imparts superhydrophobic self-cleaning properties to the material, ensuring sustained effectiveness of the photothermal conversion coating over time. This research presents a viable approach for maintaining the cleanliness and efficiency of solar energy systems.

Photothermal/magnetothermal coupled polyphenylene sulfide composite membranes for ultra-efficient and continuous seawater desalination

As the population continues to expand and industrialization gathers pace, the rate at which freshwater resources are dwindling is alarming. Solar desalination technology has shown encouraging results in generating clean water. However, solar-driven interfacial evaporation technology still faces a series of major challenges, specifically manifested in its low efficiency, poor chemical stability, and the tendency for salt crystallization to accumulate on the evaporation surface during operation. In this work, we proposed a novel magneto/photo-thermal coupled evaporator based on polyphenylene sulfide (PPS) fibrous membrane, which showed excellent high temperature and corrosion resistance. This non-contact responsive interfacial evaporator exhibited outstanding photothermal and magnetothermal conversion performance properties. Under one solar illumination, the evaporation rate of this evaporator could reach 1.52 kg m−2 h−1, corresponding to an evaporation efficiency of 91.84 %. In addition, under a magnetic field power of 2 kW m−2, the evaporator could achieve a remarkable evaporation rate of 4.2 kg m−2 h−1 under one solar illumination, with an evaporation efficiency of up to 93.77 %. Moreover, it also exhibited superb salt resistance, great mechanical properties, long-term operational stability, and outstanding dye purification property. Furthermore, by integrating the thermoelectric generator with the evaporator and utilizing the waste heat from the evaporation process to generate electricity, the efficiency of energy utilization has been improved. The interfacial evaporator opens up vast prospects for efficient and rapid clean water production, demonstrating significant potential and advantages.

Tumor Microenvironment-Responsive Biodegradable Nanomedicine for Self-Enhanced Synergistic Chemo-, Photothermal, and Chemodynamic Therapy.

The nanoscale multidrug codelivery system for synergistic therapy is an effective strategy for tumor treatment. However, the low drug delivery efficiency and poor therapeutic effects limit its application. Here, based on the coordination effect of Artemisinin (Art), quercetin (Qc), and Fe3+, we had constructed a safe and efficient carrier-free hyaluronic acid (HA)-modified Art-Fe-Qc nanoparticles (AFQ@HA NPs) for enhanced chemotherapy/photothermal therapy (PTT)-chemodynamic therapy (CDT) synergistic therapy, which achieved an ultrahigh drug loading efficiency and a multifunction anticancer strategy. The results showed that high drug loading was achieved based on drug coordination self-assembly, with Art and Qc contents of 38.6 and 42.7%, respectively. At the same time, based on the Qc-Fe coordination molecular network, the system had excellent photothermal conversion performance with an efficiency of 57.3% and could effectively inhibit the expression of HSP70, achieving enhanced PTT. Further, under the stimulation of excessive H2O2 and glutathione (GSH) in the tumor microenvironment, the AFQ@HA NPs were continuously degraded, while releasing Art and Fe3+/Fe2+ to achieve iron ion-enhanced CDT. The results of in vitro and in vivo experiments showed that AFQ@HA NPs could achieve chemotherapy-PTT-CDT synergistic therapy in response to tumor microenvironment by passively targeting and actively targeting tumor cells with CD44, demonstrating its excellent targeted antitumor effects.

Nanofiber aerogel with layered array with structure coupled photothermal/magnetothermal effect for continuous seawater desalination

The solar evaporation is susceptible to intermittent solar irradiation as well as salt crystallization deposition on the surface severely limits the evaporation efficiency. In this work, subject to inspiration of the transpiration, groove array structure and antifouling performance of banana leaves, a multifunctional photothermal/ magnetothermal coupled three-dimensional(3D) aerogel evaporator with layer-by-layer array structure was prepared by blow-spun technology which can achieve mass produced. The unique super hydrophilic vertical array structure has multi-scale high-efficiency water transport channels and the SnSe-Fe3O4 evaporation layer realizes super hydrophobic self-cleaning and excellent photothermal and magnetothermal conversion performance, which can achieve all-weather seawater desalination. The vertical array structures facilitate the reflection and refraction of light and promote the seawater convection and salt crystals absorption coupling. It could improve the photothermal conversion efficiency and salt resistance of the evaporator. Which resulted in an evaporation rate of 2.53 kg m−2h−1 under 1 sun, with solar energy conversion efficiency of 105 % and the evaporation rate is about 4.54 kg m−2h−1 at a magnetic field. Furthermore, it could purify organic pollutants in industrial wastewater and use waste heat to generate electricity. This evaporator provides a new economical and environmentally friendly solution for seawater desalination and sewage treatment.

Recent Advances in Solar Thermal Selective Coatings for Solar Power Applications: Technology Categorization, Preparation Methods, and Induced Aging Mechanisms

Solar thermal selective coatings (STSCs) are crucial for enhancing the thermal efficiency of receivers in solar power applications. Enhancing the photothermal conversion performance of STSCs is crucial for improving the thermo-economic efficiency of these sustainable high-temperature applications. Wherefore, in this study, we comprehensively review the ongoing technologies and enhanced strategies of solar thermal selective coatings, highlighting their advantages, drawbacks, technological advancements, and mechanisms. This review comprehensively examines the latest advancements in material synthesis, coating structure designs, and induced aging mechanisms of STSCs. It critically discusses the various types of STSCs, and the research techniques employed to assess photothermal performance and enhance thermal stability. Lastly, the limitations and future expectations of STSCs are also highlighted. This paper serves as a detailed guide for planning and implementing various types of STSCs in diverse solar power applications.

Imidazole-stabilized gold nanoclusters as photocatalytic initiator and crosslinker to fabricate functional hydrogel

Photopolymerization is the most widely used method to fabricate hydrogels, which hold great potentials in various fields including biomedical applications, electronic skin and flexible wearable devices. Herein, gold nanoclusters (AuNCs) were employed as both efficient photo-initiators and crosslinkers to prepare polyacrylamide (PAM) hydrogels with good mechanical properties. Firstly, an imidazole-based monomer, ImPAA, was designed and synthesized, serving as an reducing agent and ligand to prepare imidazole-stabilized AuNCs (AuNC@ImPAA) in water. Under white light irradiation, AuNC@ImPAA efficiently initiated the radical polymerization of acrylamide monomers in water via a photocatalytic mechanism. The abundant vinyl groups on the surface of AuNC@ImPAA enabled its role as a multiple covalent crosslinker, endowing the resulting hydrogel with impressive mechanical properties. The maximum tensile strength and fracture strain was 287 kPa and 591 %, respectively. Moreover, triggered by UV light, the embedded AuNC@ImPAA within the hydrogel aggregated and converted into gold nanoparticles (AuNPs), yielding an AuNP/PAM hydrogel. This hybrid AuNP/PAM hydrogel exhibited a good photothermal conversion performance, with an efficiency of 14.14 % under 660 nm laser irradiation, and its potential as a photothermal actuator was demonstrated. Thus, we provide a facile light-mediated strategy to fabricate functional hydrogel.

Fabrication of boron nitride/copper oxide@multi-walled carbon nanotubes composites for enhancing heat transfer and photothermal conversion of phase change materials

To realize the efficient storage and conversion of solar energy by phase change materials (PCMs), low photothermal conversion efficiency and poor heat transfer performance remain great challenges. Herein, polyethylene glycol (PEG)-based composite PCMs with excellent photothermal conversion performance and exceptional thermal management capability were obtained by using boron nitride/copper oxide@multi-walled carbon nanotubes (BN/CuO@MWCNTs) as the thermal conductive and photothermal conversion enhancement fillers. The results indicate that owing to the bridging effect, the introduction of CuO and MWCNTs on the BN surface can construct additional heat transfer paths, resulting in a high thermal conductivity of up to 2.35 W/(m·K) for the as-prepared PEG/BN/CuO@MWCNTs composite, which is about 9-folds enhancement than pristine PEG. Simultaneously, the supercooling degree of PEG in PEG/BN/CuO@MWCNTs is effectively suppressed due to the synergistic nucleation effect of BN, CuO and MWCNTs. Additionally, the PEG/BN/CuO@MWCNTs composites not only exhibit a high latent-heat capacity of 154.5 J/g and a high photothermal conversion efficiency of 92.2 %, but also show favorable shape stability and durable reliability. This work offers a workable solution for the synergistic enhancement of photothermal conversion and thermal management, which can effectively promote the practical application in solar energy conversion and storage.

Phase change material composites based on 3D lignin-derived porous carbon prepared by in-situ activation for efficient solar-driven energy conversion and storage

Utilization of three-dimensional biomass-derived porous carbons can effectively address issues of easy leakage, low thermal conductivity, and weak photothermal conversion of phase change materials (PCMs). This enables the production of high-performance composites for solar-induced energy collection, conversion, and storage. In this study, hierarchical lignin-derived porous carbon (HLPC), microporous lignin-derived porous carbon (MILPC) and mesoporous lignin-derived porous carbon (MELPC) were prepared through high-temperature in-situ activation using lignosulphonate (LS) as a carbon precursor and CaCO3, KOH and ZnCO3 as activators. Carbon-based PCM composites with high performance were obtained by encapsulating paraffin wax (PW) in porous carbon supports. Results demonstrated that PW/HLPC exhibited comprehensive performance superior to other tested PW composites owing to its higher specific surface area (2,358 m2/g), larger pore volume (1.1 cm3/g) and well-interconnected framework structure. Additionally, PW/HLPC displayed relatively high latent heat (123.4 kJ/kg), photothermal conversion and storage efficiency (95 %), and photoelectric conversion performance (174.5 mV). Moreover, PW/HLPC also showed better leak-proof properties at 90 °C. The cycling stability and photothermal conversion performance of PW/HLPC were superior to those of the selected crude biochar-based PW composites. This study highlights the advantages of the prepared PW/HLPC for both the high-value utilization of lignin and its practical applications in solar-induced energy harvest, conversion, and storage.

Rigid coordination environment induced MOFs to achieve an efficient photothermal conversion efficiency

A rigid coordination environment contributes significantly to stabilizing the framework structure of Metal-Organic Frameworks (MOFs) and reducing the spatial distance between functional ligands, thereby inducing charge transfer effects. In this context, achieving partial and complete coordination of TTF(py)4 in MOFs involves regulating the number and position of carboxylic acid substitutions in the ligand. Notably, TTFBDAT-Zn-MOF demonstrates a more rigid coordination environment compared to TTFBCAT-Zn-MOF. This enhanced coordination environment facilitates energy transfer between donor and acceptor units in MOFs, enabling efficient photothermal conversion performance under 808 nm excitation. The maximum temperature of TTFBDAT-Zn-MOF can reach 190 °C, while the maximum temperature of TTFBCAT-Zn-MOF can only reach 118 °C. Therefore, TTFBDAT-Zn-MOF with rigid structure has superior photothermal conversion performance.

Fe3O4/Au@SiO2 nanocomposites with recyclable and wide spectral photo-thermal conversion for a direct absorption solar collector

The Fe3O4-based photothermal materials have been widely applied for the recycling of heavy metal nanoparticles to avoid secondary pollution in the utilization of solar energy owing to excellent magnetic properties. However, the narrow absorption band of Fe3O4 or metal nanoparticles limits their capacity for solar energy harvesting. In this paper, a recyclable and wide spectral photo-thermal conversion system (Fe3O4/Au@SiO2) based on Fe3O4 nanospheres and SiO2-modified Au nanorods (NRs) is prepared. Owing to the strong coupling effect between Fe3O4 and different Au NRs, the wide and strong absorption band from 400 nm to 1100 nm is obtained. Under the influence of magnetic field, the temperature change of nanofluids (NFs) at different positions can be controlled. When the concentration is 0.0467 vol%, the solar energy absorption fraction reaches 96.50 %. Besides, the photothermal performance of Fe3O4/Au@SiO2 NFs at different flow rates is investigated and the results show that temperature rise decreases as increasing flow rate. Finally, a water evaporator device based Fe3O4/Au@SiO2 NFs is developed. The maximum water evaporation rate of 2.6 kg m−2 h−1 can be reached and the movement of evaporator on water can be operated using magnetic field, showing great photothermal conversion performance and recovery potential in practical applications.