Photothermal Conversion Performance Research Articles

Double Carbon Networks Reinforce the Thermal Storage and Thermal Transfer Properties of 1-Octadecanol Phase Change Materials.

Using thermal storage materials with excellent thermal properties in the energy utilization system enables efficient use of renewable energy sources. Organic phase change materials (PCMs) have the advantages of high heat storage density, no corrosion, and low cost, but low thermal conductivity and insufficient heat transfer capacity have always been the bottlenecks in their application. In this paper, melamine foam@ reduction graphene oxide (MF@rGO) and carbon foam@ reduction graphene oxide (CF@rGO) composite foams with double carbon networks were prepared by self-assembly method and further employed in 1-octadecinal (OD) PCMs. The microstructure, chemical composition, phase change behavior, thermal conductivity, and photothermal conversion performance of MF@rGO/OD and CF@rGO/OD were studied in detail using SEM, FTIR, Raman DSC, and LFA. The melting and solidification enthalpies of CF@rGO/OD composite PCMs were 208.3 J/g and 191.4 J/g, respectively, its thermal conductivity increased to 1.54 W/m·K, which is 6.42 times that of pure OD. The porous structure and high thermal conductivity of the double carbon network substantially enhance the efficiency of energy storage and release in composite PCMs. CF@rGO/OD composite PCMs have excellent heat storage performance and heat transfer capacity, and a wide range of application prospects in the fields of low-temperature solar heat storage, precision instrument temperature control, and intelligent buildings.

Hybrid Integration of Au Nanoplates and Ag Nanoparticles with Controlled Nanogaps via Cu2O‐mediated Galvanic Replacement Reaction: Plasmonic Catalysis and Photothermal Conversion

AbstractRational assembling of different noble metal nanocrystals with controlled nanogaps in one entity allows the efficient coupling of electromagnetic fields of each component and versatile manipulation over the overall physiochemical properties. In the present study, we report a stepwise synthetic strategy to hybridlike assemble Au nanoplate and Ag nanoparticles without direct physical contact. Particularly, the success of current work relies on the conformal coating of Cu2O over the Au nanoplate as an intermediate layer, followed by the in situ formation of Ag nanoparticles via the galvanic replacement reaction between Cu2O and Ag+. With the anchoring of Ag nanoparticles over the Cu2O‐wrapped Au nanoplate, the resulting hybrid nanostructures exhibit noticeable multiple plasmonic absorptions across the UV‐vis‐NIR region. The potential use as the plasmonic catalyst for current Au@Cu2O‐Ag hybrid products is validated using reduction of 4‐nitrophenol as the model reaction, where the catalytic performance is greatly improved by the UV‐vis light irradiation. They also exhibit satisfactory photothermal conversion performance under the irradiation of Xe lamp. The current work provides a niche strategy to create noble‐metal hybrid nanostructures with controlled interparticle distance and tunable plasmonic properties, could be extended to other noble metal or alloys.

Fabrication of graphene-rapped melamine sponge and its photothermal adsorption on viscous oil spill

Graphene oxide melamine sponges (GOMSs) were prepared by impregnating melamine sponge (MS) with graphene oxide (GO) dispersion. Thereafter, reduced graphene oxide melamine sponges (HGOMSs) were obtained by one-step heat treatment of GOMSs, and the effects of heat treatment and GO load on sponge structure, hydrophobicity/ lipophilicity, photothermal properties, mechanical properties and light-aided adsorption performances were evaluated. The results show that heat treatment under 400 °C is an optimum choice. A small amount of graphene could effectively wrap on the melamine sponge skeleton and closely combined with the sponge. This effectively wrapped structure can not only improve the photothermal and mechanical properties of the sponge, but also retain the rich pore structure of the sponge to provide sufficient space for oil adsorption. HGOMS prepared under 400 °C with 1 mg·ml−1 of GO concentration shows an average light absorption rate of 84.4% in the full solar spectral range. Under 1 sun illumination in air, the surface can quickly rise to 99.4 °C, and the bottom surface is 72.8 °C, showing excellent photothermal conversion performance. The saturated adsorption capacity on heavy oil reached 103.2 g·g−1 under 1 sun illumination. The material was reused through mechanical extrusion method. After 10 times of adsorption- extrusion operations, its saturated adsorption capacity still retained more than 80% of the first time. These characteristics make HGOMS an energy efficient and reusable adsorbent for oil spill.

Constructing a hierarchical coating with photothermal superhydrophobic property by spraying and modification on polyurethane foam for anti-icing and deicing

Superhydrophobic material with photothermal conversion property is considered as a promising candidate in practical application because of its double abilities: both superhydrophobic anti-icing and photothermal deicing. Therefore, in this work, we employed a polyurethane (PU) foam with three-dimensional porous grid structure as the skeleton and carbon nanotubes (CNTs) as the photothermal conversion materials to construct a hierarchical coating with photothermal superhydrophobic property by spraying CNTs/SiO2 and modification of polydimethylsiloxane (PDMS), where a dual-size micro/nano structure was formed by adsorbing and fixing these CNTs-entangled SiO2 nanoparticles into PU foam to enhance the superhydrophobicity and light absorption capacity of coating. In this case, the water contact angle of the hierarchical coating reached up to 157.0°, accompanied by a rolling angle of 3.2°, while the water droplet hitting its wall can fully rebound within 27 ms. Importantly, the formation of hierarchical structure and the incorporation of CNTs contributed to an enhancement of light absorbance to 97.1 %, which was able to warm the coating surface up to 101.9 °C at 1 kW m−2 after 300 s illumination. Noteworthily, the surface temperature of the coating can be raised to 62.5 °C within 15 min to achieve deicing under a low ambient temperature of −20 °C. In addition, a remarkable stability and wear resistance were maintained after 10 freeze–thaw cycles and 20 friction cycles. Consequently, it can be concluded that the developed hierarchical coating with exceptional superhydrophobicity and excellent photothermal conversion performance was expected to be a potential substitute for anti-icing and deicing.

Intelligent bamboo: A splendid flame retardant, fire warning and photothermal sterilization nanocoating via low-temperature evaporation induced self-assembly

The application of bamboo to assist carbon neutral strategy has attracted worldwide attention due to its naturally carbon-negative property. However, the inherent defects of flammable and mildewed make bamboo encounter a bottleneck in its application. Hence, an intelligent bamboo (IB) with integrated performances of stable connection, high-temperature resistance, reliable fire warning and splendid photothermal sterilization properties was constructed via low-temperature evaporation induced self-assembly strategy. The hydrogen bonding, coordination complexes, van der Waals forces, and electrostatic forces can be formed between Ti3C2Tx (MXene) and pre-treated bamboo substrate (TB). The optimized bamboo-based fire alarm sensor (AM@TB) exhibits significant improvement in flame retardant properties, e.g., the limiting oxygen index (LOI) value of AM@TB8-2 was 61.4%, surpassing TB by an impressive margin of 65.8% and the vertical burning test reach the UL94 V-0 rating. Besides the PHRR (heat release rate) of AM@TB8-2 was decreased 80.3% compared to TB. The residual mass of AM@TB8-2 is 34.5%, which is 1.6 times higher than TB. Additionally, the AM@TB8-2 presents a sensitive fire warning response (∼2 s) and reliable repeatability. Furthermore, based on the outstanding photothermal conversion performance of MXene, AM@TB8-2 demonstrates predominant sterilization efficacy after a near-infrared laser (NIRL) illumination. Therefore, this work provides inspiration for the design and fabrication of high-performance IB that combine fire safety and antimicrobial properties.

Fabrication of Robust Superhydrophobic Polyester Fabrics with Photothermal Conversion and Oil-Water Separation Performance through Deposition of Natural Polyphenols.

Superhydrophobic polyester (PET) fabrics were created by increasing fabric surface roughness and decreasing surface energy through interactions between natural polyphenols, ferrous sulfate heptahydrate, and hexadecyltrimethoxysilane. The superhydrophobic fabric can be obtained with different natural polyphenols, including tannic acid, ferulic acid, gallic acid, guaiacol, and caffeic acid. Durability tests were carried out on the superhydrophobic PET fabric, investigating resistance to washing, rubbing, UV aging, acids, alkalis, and organic reagents. The results demonstrate the stability and versatility of modified PET in complex environments. The modified superhydrophobic PET fabric exhibited exceptional oil-water separation and self-cleaning properties, exhibiting a water contact angle of 161.3° and a sliding angle of 4°. In addition, the modified fabric demonstrated a remarkable photothermal conversion efficiency, with the surface temperature increasing from 29.1 to 72 °C in 300 s, and it maintained a degree of photothermal conversion capability even upon completion of four cycles. This study offers novel perspectives on extending the utilization of natural polyphenols for constructing durable, robust, and multifunctional superhydrophobic fabrics.

Lignin with enhanced photothermal performance for the preparation of a sustainable solar-driven double-layer biomass evaporator

The undesirable photothermal conversion performance of lignin limits the potential for directing use as a photothermal conversion material, and no strategies have been found to enhance the photothermal conversion efficiency of lignin. Herein, three modified lignin of corn stover alkali lignin (DEHL), pine alkali lignin (DAL) and birch alkali lignin (DTAL) with excellent photothermal conversion efficiency and fast temperature response was prepared by a one-step iodocyclohexane (ICH) activation strategy. The maximum temperature of the DEHL, DAL and DTAL can reach to 138 °C, 157 °C, and 172 °C in 12 min under 0.15 W/cm2 compared to the native lignin. Moreover, the photothermal conversion efficiency of the DEHL, DAL and DTAL was calculated to be 36.52 %, 36.19 % and 43.19 % by ICH modification. The photothermal enhancement mechanism of the modified lignin was determined by various characterizations and simulation calculations, which can be summarized that the activation of lignin by ICH breaks the molecular structure and reduces the methoxy content of the lignin, which enhances the intermolecular bonding, and the hydrogen bonding between the phenolic hydroxyl groups strengthens the π-π intermolecular interactions between the benzene rings. In addition, a double-layer biomass aerogel evaporator (DAGS) with cost-friendly and superior evaporation performance was synthesized by chemical cross-linking using DTAL as the photothermal agent. The evaporation rate of 4DAGS can be as high as 2.063, 2.024, 2.259 and 2.447 kg/(m2∙h) in water, 3.5 wt% seawater, and 200 mg/L of MG or MB wastewater under 1sun. And no salt was observed on the surface of the 4DAGS after a long period of 36 h of operation in 3.5 wt% seawater, suggesting the outstanding salt-reject performance of the aerogel. Furthermore, there is no structural damage and chemical decomposition found on 4DAGS after 24 h immersion in NaOH and HCl solutions, demonstrating the excellent acid and alkali resistance of the synthesized aerogels. This work may offer a novel strategy for the photothermal performance enhancement of lignin and expand the potential application in solar-driven evaporation materials.

2D silicene nanosheets-loaded coating for combating implant-associated infection

Implant-associated infection (IAI) is an unsolved problem in orthopaedics. Current therapies, including antibiotics and surgical debridement, can lead severe clinical and financial burdens on patients. Therefore, there is an urgent need to reinforce the inherent antibacterial properties of implants. Recently, two-dimensional (2D) silicene nanosheets (SNs) have gained increasing attention in biomedical fields owing to their considerable biocompatibility, biodegradability and strong photothermal-conversion performance. Herein, a dual-functional photosensitive coating on a Ti substrate (denoted as TPSNs) was rationally fabricated for bacterial inhibition and osteogenesis promotion. For the first time, SNs were loaded onto the surface of implants. Hyperthermia generated by the SNs and polydopamine (PDA) coating under 808 nm laser irradiation achieved the in vitro anti-bacterial efficiency of 90.7 ± 2.4 % for S. aureus and 88.0 ± 5.8 % for E. coli, respectively. In addition, TPSNs exhibited promising biocompatibility for the promotion of BMSC (bone marrow mesenchymal stem cells) proliferation and spreading. The presence of silicon (Si) in TPSNs contributed to the improved osteogenic differentiation of BMSCs, elevating the expressions of RUNX2 and OCN. In animal experiments, the combination of TPSNs with photothermal therapy (PTT) achieved an anti-bacterial efficiency of 89.2 % ± 1.6 % against S. aureus. Furthermore, TPSNs significantly improved bone-implant osseointegration in vivo. Overall, the development of a dual-functional TPSNs coating provides a new strategy for combating IAI.

Environmental-friendly biomass-based Janus ink/urushiol modified cotton fabric for efficient solar-driven interfacial evaporation

Much attention has been paid to the interfacial solar-thermal conversion method for water resource purification. According to the hydrophilicity of ink carbon particles and the amphiphilicity of urushiol molecules (the main compound of Chinese lacquer), a novel environmentally friendly biomass Janus ink/urushiol modified cotton fabric was successfully prepared and exhibited one hydrophilic side and one hydrophobic side through simple immersion and spraying treatments. The Janus fabric displayed excellent water transport behavior, mechanical stability, thermal conductivity, and photothermal conversion performance. Under one stimulated solar radiation, the temperature of the Janus fabric increased to 85 °C in 2 min. Additionally, a photothermal vapor device prepared using a polyethylene ring and the Janus fabric demonstrated a high conversion efficiency of 94.3% with an impressive evaporation rate of 1.64 kg m−2h−1, which was 3.35 times the rate of water evaporation in the absence of the modified fabric. The Janus fabric showed satisfactory resistance to ultraviolet radiation and pH values. After 8 cycles (every 10 h) of exposure to outdoor sunlight, the modified fabric showed a slightly decreased evaporation rate, which could be restored to the previous level by re-spraying ink on the modified fabric. In the concentrated salt solutions, the solar-driven evaporator displayed excellent salt rejection capacity. During the desalination of high-concentration saline water, the Janus fabric showed acceptable diurnal correspondence. After desalination, the water quality reached the required standards for drinking water. In particular, the B3+ content droppingto 0.33 mg L−1(below the thresholdof 0.5 mg L−1). The solar steam generator also showed remarkable purifying capabilities for wastewater containing heavy metals and organic dyes. The Janus ink/urushiol fabric, prepared in an easy way, has a wide range of applications in seawater desalination and sewage treatment, which can be applied for mitigation of freshwater crises and environmental remediation.

Fabrication of targeted PDA-Hemin-Dox-FA nanoplatform for enhanced chemodynamic therapy synergized with chemo/photothermal therapy

Chemotherapy (CT) is widely used in clinical practice due to its simple and convenient steps, but its characteristics of systemic administration also results in a lack of targeting and a tendency to develop drug resistance, which greatly limits its therapeutic effect. In order to overcome these problems, a PDA-Hemin-Dox-FA (PHDF) nanoplatform was constructed in this work for the combined treatment of tumors. Firstly, hemin was introduced into the self-polymerization of dopamine to synthesize PDA-Hmein (PH) nanoparticles. Then, the chemotherapy drug doxorubicin (Dox) and targeted folic acid (FA) were loaded onto PH surfaces through Schiff base and amide bonds respectively to construct PHDF. When PHDF enters the tumor cells through the targeting guidance of FA, the acidic microenvironment of the tumor will induce the cleavage of the Schiff base bond in PHDF to release Dox. The presence of hemin makes PHDF have high Fenton-like activity, which generate large amount of·OH to perform chemodynamic therapy (CDT). Driven by near infrared laser light, PHDF exhibited wonderful photo-thermal conversion performance which not only brings excellent photo-thermal therapy (PTT) effect, but also promotes the uptake of Dox and the production of·OH, leading to enhanced CT and CDT efficacy. Taken together, the PHDF nanoplatform constructed in this study shows good CT/PTT/CDT combined therapy against tumor cells and it also provides a promising alternative for the combination therapy of tumors.

Superhydrophobic, flexible and high thermal stable ANFs/CNTs film for controllable light driven actuators

Superhydrophobic and light-responsive actuators (SLRAs) can be driven to move on water surface remotely and in a non-contact manner, and have shown promising applications in soft robotics, environmental protection, etc. It remains a big challenge to develop high performance SLRAs with excellent thermal stability, fast light responsivity and controllable motion. Here, we propose a layer-by-layer vacuum filtration method to prepare flexible, freestanding and superhydrophobic composite films composed of alternately deposited oleylamine modified acid carbon nanotubes (O-ACNTs) and aramid nanofibers (ANFs). The composite film has excellent thermal stability with the maximum weight loss rate temperature as high as 520 ℃. The closely packed structure and strong interlayer interaction ensure the surface stability and durability of the composite film. The composite film possesses excellent photothermal conversion performance, and can maintain the structure integrity without deformation when its surface temperature reaches 208 °C. When used as a self-propelled actuator, the SLRA film can response to the light quickly and move on the water surface, and the motion speed and direction can be controlled by adjusting the irradiation intensity and position. The outstanding thermal stability guarantees the stability and reliability of the self-propelled motions. The present study opens a new avenue to design high performance SLRAs.

Ligand Mediation for Tunable and Oxide Suppressed Surface Gold-Decorated Liquid Metal Nanoparticles.

Gallium-based liquid metal systems hold vast potential in materials science. However, maximizing their possibilities is hindered by gallium's native oxideand interfacial functionalization. In this study, small-molecule ligands are adopted as surfactants to modify the surface of eutectic gallium indium (EGaIn) nanoparticles and suppress oxidation. Different p-aniline derivatives are explored. Next, the reduction of chloroanric acid (HAuCl4 ) onto these p-aniline ligand modified EGaIn nanoparticles is investigated to produce gold-decorated EGaIn nanosystems. It is found that by altering the concentrations of HAuCl4 or the p-aniline ligand, the formation of gold nanoparticles (AuNPs) on EGaIn can be manipulated. The reduction of interfacial oxidation and presence of AuNPs enhances electrical conductivity, plasmonic performance, wettability, stability, and photothermal performance of all the p-aniline derivative modified EGaIn. Of these, EGaIn nanoparticles covered with the ligand of p-aminobenzoic acid offer the most evenly distributed AuNPs decoration and perfect elimination of gallium oxides, resulting in the augmented electrical conductivity, and highest wettability suitable for patterning, enhanced aqueous stability, and favorable photothermal properties. The proof-of-concept application in photothermal therapy of cancer cells demonstrates significantly enhanced photothermal conversion performance along with good biocompatibility. Due to such unique characteristics, the developed gold-decorated EGaIn nanodroplets are expected to offer significant potential in precise medicine.

Hydroxyl functionalized MWCNT nanofluids with excellent photothermal conversion performance in direct absorption solar collectors

Developing novel nanofluids with good stability, excellent photothermal conversion performance, and appropriate thermophysical properties is of great importance in promoting the practical utilization of nanofluids in solar collectors. In this work, hydroxyl multi-walled carbon nanotube (MWCNT-OH) nanofluids are proposed, which can achieve a high photothermal conversion of 88.2 % at a concentration of 20 ppm under 1-sun irradiation. Both the sedimentation experiment and spectrophotometer analysis prove that the prepared MWCNT-OH nanofluids have excellent stability. The influence of hydroxyl functionalization, MWCNT-OH concentrations, and temperature on the thermophysical and optical properties is analyzed. Moreover, the comparison between MWCNT-based nanofluids with different functionalization reported in the literature and our work is carried out, the results show that MWCNT-OH nanofluids in our work outperform MWCNT-based nanofluids with other types of functionalization reported in the literature. This work may promote the use of MWCNT-OH nanofluids as working fluids in solar collectors.

Synergistic enhancement of optical properties in Ca/Ni co-doped LaFeO3 perovskite coatings enabling high-temperature photothermal conversion

Perovskite-type oxides (ABO3) are widely acknowledged as novel light-absorbing materials owing to their adaptable composition, distinctive oxidation states, and customizable physicochemical properties. In this study, we reported a series of A-site or A/B-sites doped LaFeO3-based ceramic coatings for photothermal conversion. An exhaustive investigation was undertaken to explore the effects of doping element on the microstructure, microchemistry, and optical properties of the ceramic coating. Among all the samples, the La0.5Ca0.5Fe0.95Ni0.05O3 coating exhibits the highest absorptivity in the solar spectrum (300–2500 nm) and in the wavelength range of 0.3–14 μm, reaching 92.2 % and 88.1 %, respectively. Furthermore, it demonstrated the superior photothermal conversion performance under solar and infrared radiation. Complementary first-principles calculations provide fundamental principles for comprehending the light absorption enhancement mechanisms in LaFeO3-based materials, revealing the complex interplays between crystal structure, band structure, and light absorption. The experimental findings, along with the results of first-principles calculations, demonstrate that the doping of Ca or Ca and Ni can effectively reduce the bandgaps and induce lattice distortions, thereby enhancing the light absorption in the visible and infrared wavebands. This work presents a facile method to prepare LaFeO3-based coatings with different morphologies, providing a novel option for high-temperature photothermal conversion applications.

Hydrophobic organogel sorbent and its coated porous substrates for efficient oil/water emulsion separation and effective spilled oil remediation

Frequent offshore oil leakage accidents and large quantities of oily-wastewater produced in industry and daily life bring huge challenges to global water purification. The adaptability and stability of organogels as adsorbent materials have shown wide application prospects in the field of oil-water separation. Herein, the organogels displayed stable hydrophobic/lipophilic properties with high absorption ability (1200 wt./wt%), efficient sorption of multiple emulsions (>99.0%), and good reusability. More importantly, the organogels were successfully assembled with 2D/3D substrates to achieve excellent sorption capacity (102.5 g/g) and recycling performance (50 cycles). The gel-carbon black assembled on MS (GCB-MS) sorbent with excellent photothermal conversion performance, and can rapidly heat the surface to 70.4 °C under 1.0 sunlight radiation (1.0 kW/m2) and achieved an ultra-high sorption capacity of about 103 g/g for viscous crude oil. Meanwhile, the GCB-MS was combined with a pump to build continuous oil spill cleaning equipment to achieve a super-fast cleanup rate of 6.83 g/min. The developed hydrophobic organogels had been expanded unprecedentedly to realize the comprehensive treatment of oily-wastewater in complex environments, including layered oils, emulsions, and viscous crude oil spill, which provided an effective path for the comprehensive treatment of oily wastewater in complex environments.

Bionic research of photothermal conversion performance based on butterfly wings

AbstractAs the demand for sustainable construction practices increases, innovative ideas are being explored for the construction of insulated wall panels in contemporary buildings. The butterfly is a remarkable organism that uses a thermostatic mechanism to regulate its body temperature. The microstructure on the surface of its wing scales is responsible for reflecting incident light multiple times, extending the optical path, and increasing the light absorption, thus ensuring that its body temperature remains stable. This microstructure, also known as the light capture structure, has been simulated and analyzed using ANSYS software. The results indicate that this structure can improve the light‐thermal conversion efficiency in the illuminated region, thus increasing the local heat using light radiation. Additionally, due to the unique arrangement of units in the light capture structure, the heat exchange rate with air is significantly reduced, resulting in a low heat flux. Therefore, if this butterfly‐like trapped light structure is applied to the insulated wall panels, the requirements of modern architectural concepts can be realized.

Rapid detection of Salmonella in food matrices by photonic PCR based on the photothermal effect of Fe3O4.

Salmonella causes most deaths from diarrheal disease worldwide. Therefore, Salmonella must be accurately and quickly detected, even in complex food matrices, which is difficult to achieve using conventional culture methods. Here we propose a novel photonic polymerase chain reaction (PCR) method based on ferroferric oxide (Fe3O4) for the detection of Salmonella typhimurium in complex samples. Owing to the great photothermal conversion performance of Fe3O4, rapid thermal cycling could be accomplished. Our optimized photonic PCR system specifically detected Salmonella typhimurium in complex food matrices within 50min. Quantitative data showed a limit of detection up to 102 CFU/mL in food samples. This method is suitable for the detection of all pathogenic microorganisms and is universal.

Experimental comparison of the photothermal conversion performance of coal and plant soot nanofluids for direct absorption solar collectors

Direct absorption solar collectors (DASCs) based on nanofluids improve the thermal utilization efficiency of solar energy. In this study, the waste soot materials obtained from coal and plant biomass combustion were recycled. Deionized water was used as the basic fluid. A two-stage method was used to prepare coal soot (CS) and plant soot (PS) nanofluids. Detailed investigations and comparisons of the thermal conductivity and light-absorbing characteristics of the two fluids were performed. The results suggested that the introduction of soot nanoparticles improved the heat transfer and light-absorbing capacities of the base fluid and both thermal conductivity and optical absorption of soot nanofluids were positively correlated with the soot nanoparticle loading. Subsequently, photothermal conversion experiments were conducted internally and externally. The experimental results indicated that the PS nanofluids could absorb incident light radiation more efficiently and converted it into thermal energy. Specifically, the overall photothermal conversion efficiency of the PS nanofluid at a maximum mass fraction of 0.02% in the solar simulator was 55.7%, which was approximately 9.8% higher than that of the CS nanofluid. In addition, 42.3 °C and 44 °C were the maximum temperature increases under natural sunlight for the CS nanofluid and PS nanofluid, respectively. Notably, the waste soot materials are low cost and easily available. Therefore, this work demonstrates that recycled soot nanofluids, especially PS nanofluids, are promising candidates for application in DASCs systems.

Sensible heat thermal energy storage performance of mono and blended nanofluids in a free convective-radiation inclined system

The photothermal conversion performance (PCP) of a nanofluid-based solar energy system is investigated numerically and experimentally. The impacts of particle size, volume concentration, nanoparticle type, base fluid type and collector inclination angle on the PCP are investigated. It is observed that using nanoparticles improves the ability to absorb solar energy. Temperature gain is 2.2, 3.2, 3.8, 4.2, and 9 times better than pure water for water-based Al, Al2O3, Au, Cu, and Graphite mono nanofluids, respectively. Interestingly, blended nanofluids containing the same nanoparticles significantly argument the optical properties, with useful heat enhancement ranging from 62.8 (mono) to 194 kJ/kg (hybrid). However, the collector's inclination angle, which ranges from 0 to 60°, has a negative impact on the PCP by reducing the solar radiation absorption of the nanofluids due to a decrease in the radiation penetrating the collector. Furthermore, as nanoparticle size increases, so does the thermal performance of the nanofluid. An experimental investigation is carried out for pure water and nanofluid at various wind speeds and solar irradiation levels ranging from 1 to 4 m/s and 200–1000 W/m2, respectively, to validate the numerical results.

A Review on Microencapsulated Phase‐Change Materials: Preparation, Photothermal Conversion Performance, Energy Storage, and Application

The leakage‐prone disadvantage of pure phase change materials (PCMs) has hampered their practical application, and the encapsulation technology of PCMs has been favored for its ability to mitigate leakage. Combining large solar reserves with energy storage technology can increase the utilization of renewable energy and broaden the application of microencapsulated phase change materials (MEPCMs) in the field of solar energy. First, the fabrication technologies of MEPCMs, which include physical, chemical, and physical–chemical methods, have been comprehensively elaborated in this article. Second, the characteristics of different methods are also summarized. Then, the influences of MEPCMs properties on their thermal storage capacity have been clarified. This work shows the supercooling, phase separation, mechanical properties, encapsulation efficiency, and photothermal conversion performance of MEPCMs. Modification of MEPCMs by metal materials and their oxides, carbon, and semiconductor materials to improve the light absorption capacity. In addition, two‐dimensional materials such as MXene have been widely used to improve the photothermal properties of MEPCMs. Finally, the applications of MEPCMs in the construction, slurry, textile, and food industries are discussed. This work can provide some useful guidance for the optimization strategies of the photothermal conversion performance and practical applications of MEPCMs.