Stabilized Conversion Efficiency Research Articles

Enhancing stability of copper-based catalysts by regulating of oxygen vacancy for resourcing HCl waste gas

The utilization of copper-based catalysts for converting by-product hydrogen chloride (HCl) into chlorine gas (Cl2) offers a promising method for efficient management of HCl waste gas. However, a significant challenge in this process lies in catalyst deactivation, primarily attributed to the loss of active component in the form of Cu-Cl. In this study, we synthesized a Cu2.4CeV0.5Ox catalyst that exhibited remarkable performance, achieving a space-time yield of 2.26 g Cl2/gcat*h with stable conversion efficiency at approximately 83 % maintained over 600 h. This level of stability represents a substantial improvement compared to previous studies of copper-based catalysts. In-situ DRFITS combined with ToF-SIMS confirms the reduction evolution of metal-Cl bonds. Additionally, ab-initio calculations elucidated that the rate-limiting step involves oxygen vacancy replenishment by O2 rather than Cl over CeO2 and CeVO4, thereby inhibiting Cu-Cl bond formation. This study introduces a novel approach for efficienct treatment of HCl waste gas, paving the way for its potential industrial application.

Accretion disks properties around regular black hole solutions obtained from non-linear electrodynamics

We investigate a family of spherically symmetric, static, charged regular black hole solutions derived within the framework of Einstein-nonlinear electrodynamics. Our study focuses on examining the characteristics of accretion disks in the spacetimes described by the Dymnikova and Fan-Wang solutions. We explore circular geodesics of test particles and calculate various properties, including the radius of the innermost stable circular orbit, radiant energy, temperature, and conversion efficiency of accretion mass into radiation. We employ the Novikov-Thorne-Page thin accretion disk model as a background. By comparing our findings with those obtained in the Schwarzschild black hole case, we reveal significant modifications in the overall spectral properties. Specifically, we observe an increase in the energy emitted from the disk surface, resulting in higher temperatures for the accretion disks under certain values of the free parameters. Consequently, we note an enhanced efficiency of mass conversion into radiation compared to the Schwarzschild spacetime.

Photothermal controlled antibacterial Ta4C3Tx-AgNPs/nanocellulose bioplastic food packaging

Uncontrolled antibacterial, insufficient barrier and low strength are the bottlenecks of food packaging applications. Herein, Ta4C3Tx nanosheet as a template was used to prepare Ta4C3Tx immobilized silver nanoparticles (Ta4C3Tx-AgNPs), which was compounded with nanocellulose to obtain high-strength and high barrier controllable bactericidal nanocellulose-based bioplastic packaging (CTa-Ag). The results indicated that due to the hydrogen bonding between nanocellulose and Ta4C3Tx, the bridging effect of QCS (quaternized chitosan) and the filling of Ta4C3Tx-AgNPs, the CTa-Ag had tightly stacked microstructure, which endowed them with excellent mechanical properties (4.0 GPa), ultra-low oxygen permeability (0.009 cm3/m2·d·atm) and stable photothermal conversion efficiency. Importantly, the packaging exhibits the ability to control the release of antibacterial active ingredients. Moreover, the synergistic effects of controllable release of nano active factors, photothermal and photocatalysis in CTa-Ag gave it long-lasting antibacterial properties. This study brings new insights into the design and manufacture of multifunctional, controllable and long-lasting antibacterial bioplastic food packaging.

Study on the influence of micro-alkali texturing and micro-alkali polishing process on the passivation and contact performance of n-TOPCon solar cells

The matching between the morphology of the backside of n-TOPCon solar cells and the tunnel oxide/n + polysilicon structure is the key to achieving high efficiency. In this work, based on the requirement of edge isolation, micro-alkali polishing and micro-alkali texturing were performed on the acid-polishing back surface. Their effects on surface morphology, passivation effect, contact resistance, and photoelectric conversion efficiency were investigated. Adding a short-time micro-alkali texturing process after acid polishing can form a surface morphology with both regional polishing and local microtexture. This can improve the contact characteristics without significantly affecting the passivation characteristics, enabling solar cells to achieve higher FF (83.30%) and average efficiency (24.15%). Compared with the acid polishing sample, the efficiency of the micro-alkali texturing sample is increased by 0.12%. The deterioration of ohmic contact caused by alkali polishing has not been eliminated by optimizing the reaction process of alkali polishing. The study of different surface morphologies-modified samples under different tunnel oxide layer growth time, also reveals the difference in the influence of tunnel oxide layer characteristics on samples with different morphologies. The acid-polishing samples show more stable FF and conversion efficiency at different thermal oxidation time, and the micro-alkali texturing samples have a significant FF advantage at shorter thermal oxidation time. These studies can be applied and validated in the photovoltaic industry.

Controlled crystallization and surface engineering of mixed-halide γ-CsPbI2Br inorganic perovskites via guanidinium iodide additive in air-processed perovskite solar cells

In this report, we demonstrate enlarged grain size (up to ∼3 μm) in ambient-stable black γ-phase CsPbI2Br thin films through the regulated addition of guanidinium iodide (GAI) as an effective volatile additive. Nuclear magnetic resonance (NMR) and X-ray photoelectron spectroscopy (XPS) measurements indicate the complete sublimation of GAI following annealing, with no inclusion inside the final γ-CsPbI2Br perovskite lattice. GAI is found to participate by retarding the cation–anion reaction via the Cs+ and GA+ cation-exchange process. We find that inorganic perovskite solar cells (IPSCs) devices made from (CsPbI2Br)0.925 + 0.075 GAI and a phenyltrimethylammonium chloride (PTACl) passivation retain a solar-friendly band-gap of 1.91 eV and excellent device performance, with the best open-circuit voltage reaching as high as 1.34 V, with highly reproducible and stable photo conversion efficiencies of 16.88% (for 0.09 cm2) and 15.60% (large area 1 cm2) under ambient conditions. Photostability analysis further demonstrated negligible efficiency loss over 1000 h under continuous one-sun equivalent illumination, indicating GAI additive as a promising approach toward ambient stable, all-inorganic high-efficiency solar cells.

Material Design of Bimetallic Catalysts on Nanofibers for Highly Efficient Catalytic Reduction of 4-Nitrophenol.

In this study, CuO-TiO2 nanofiber catalysts were fabricated by an electrospinning process, followed by thermal annealing at various temperatures ranging from 300 to 700 °C. The phase transformation from CuO to metallic Cu was carried out through immersion treatment in NaBH4 solution. The resulting CuO-TiO2 and Cu-CuO-TiO2 nanofibrous mats were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and Brunauer-Emmett-Teller (BET) analysis. The results revealed that the crystalline phase composition of the nanofibrous mats considerably affected the efficiency of photocatalytic reduction, where the CuO-TiO2 catalysts with a predominant anatase content was found to be more photoactive than the rutile phase. Similarly, the presence of both Cu and CuO species was more beneficial for promoting the activity of fibers by acting as an interim location for facilitating the electron transfer. The fabricated Cu-CuO-TiO2 nanofibrous mat with a ratio presented high conversion (∼99%) within several minutes with the apparent pseudo-first-order rate constant of 0.42 and 0.50 min-1 in the absence and presence of UV light irradiation as well as excellent stability in recycling runs with a stable conversion efficiency of 97% or higher over five successive catalytic cycles.

Stable high conversion efficiency of Quasi-2D perovskite solar cells via potassium iodide as additive

Although two-dimensional (2D) perovskite is more stable than three-dimensional (3D) perovskite, its poor film quality and low photoelectric conversion efficiency are still the focuses of researchers. In this article, we introduce a simple and effective method to modify the quasi-2D (BA)2(MA)3Pb4I13 perovskite solar cells by introducing potassium iodide as an additive. We found that the introducing K ion made perovskite film more compact, reduced the number of grain boundaries and regulated the band alignment. Besides, the incorporation of K+ reduced the nonradiative recombination and hysteresis effect of the device. As a result, the power conversion efficiency (PCE) of solar cells increased from initial 13.91% to 16.82% under optimized concentration of 16% (mole ratio compared to N-butyl ammonium iodide BAI). What is more, the device with K+ modification showed excellent environmental stability, which could maintain 95% of their original efficiency after 720 h under ambient air condition, whereas the pristine devices without K+ only keep 53% of their initial efficiency and the thermal stability has also been improved. This result provides a simple and promising method through additive engineering to achieve high PCE and stable quasi-2D perovskite solar cells.

Catalytic Activity and Coke Resistance of Gasification Slag-Supported Ni Catalysts during Steam Reforming of Plastic Pyrolysis Gas

Pyrolysis gas from polyolefinic plastic waste is a hydrocarbon-rich feedstock for sustainable syngas production. The effect of Cr, Mo, and W promoters on the activity of gasification slag-supported Ni catalysts during the reforming of plastic pyrolysis gas was investigated (polyethylene and polypropylene mixed feedstock, Ni:promoter molar ratio = 4.5, 800 °C, steam-to-carbon molar ratio of 7). Based on 3 h reforming tests, all catalysts showed stable conversion efficiency, suggesting that gasification slag from municipal solid waste is a promising replacement material for traditionally used alumina supports. Moreover, the slag demonstrated good thermal stability and potential for catalyst recycling, justifying the economic benefit of valorizing the material. Interestingly, interaction between slags and promoters is evidenced by the formation of CaWO4 and CaMoO4 phases, which may have an impact on the reforming activity of bimetallic catalysts. Among the studied catalysts, the highest conversion efficiency of hydrocarbon compounds (76%), highest H2 (122.65 mmol Lfeed–1) and CO (49.34 mmol Lfeed–1) yields, and lowest coke deposition (0.06 wt %) were demonstrated by the Ni–Mo catalyst. The superior performance of Ni–Mo was accompanied by the growth of carbon nanotubes via a tip-growth mechanism, which was not observed in other catalysts. Spherical carbon nanocages and filamentous carbon nanofibers predominated in coke deposits of Ni, Ni–W, and Ni–Cr. The high syngas production efficiency of Ni–Mo could be attributed to the dispersion of metal by the growing carbon nanotubes providing the reaction sites for reforming and coke gasification reactions. Owing to these properties, Ni catalyst promoted by Mo and loaded on a gasification support has high potential for the syngas production from plastic pyrolysis gas.

Polymethyl Methacrylate/Polypyrrole Porous Membranes Prepared by Breath Figure Method with Superior Salt Resistance for High‐Efficiency Interfacial Solar Evaporation

A simple method for the fabrication of the double‐layer and salt‐resistant evaporator consists of a porous structure polymethyl methacrylate/polypyrrole (PMMA/PPy) photothermal membrane as the top layer and plant fiber‐wrapped expanded polyethylene (EPE) foam as the insulating bottom layer is demonstrated for the first time for efficient solar‐driven interfacial evaporation. For the fabrication of the porous PMMA/PPy membranes, a straightforward and affordable breath figure approach is used. Owing to its porous structure with low tortuosity and large pore size, excellent insulation of the EPE sponge, and the strong light absorption of PPy coating, the as‐prepared PMMA/PPy evaporator exhibits a stable photothermal conversion efficiency of 95.3%, corresponding to a high evaporation rate of 1.65 kg m−2 h−1, and outstanding salt resistance performance in 15%wt NaCl solution (evaporation rate of 1.54 kg m−2 h−1), under 1 sun irradiation, thus showing great potential for practical desalination application by combination with its simple, cost‐efficient, and easily scale‐up fabrication process. More importantly, the findings herein may also provide a versatile method for the design of novel photothermal materials with large pores using various polymers as substrates without limitation by shape or size only via a simple and “green” breath figure approach.

Enhancing water resistance of Pt nanoparticles by tailoring microenvironment of hollow ZSM-5 for efficient benzene oxidation

Pt works particularly well as a nanoparticle catalyst in the elimination of atmospheric pollutants, but its application is severely hampered by agglomeration and evenpoisoning in the presence of moisture. Hereby, a novel catalyst Pt@O-ZSM-5@OTS was synthesized to protect Pt, namely 0.5 wt% Pt was integrated into hollow ZSM-5 and subsequently coated hydrophobic octadecyltrichlorosilane (OTS) akin to the waterproof carapace. With the aid of various characterization techniques, the hybrid catalyst induced multiple marked features, such as dual-shell structure, hydrophobic microenvironment, and encapsulated active sites. Under excessively humid conditions (10 vol% H2O), the optimized Pt@O-ZSM-5@OTS2 exhibited a stable benzene conversion efficiency of 100 % for 120 h and outperformed the catalysts reported so far. Even reducing the reaction temperature to 170 °C, the conversion of benzene also reached 85 %, far exceeding the performance of untreated Pt@O-ZSM-5 (∼50 %). The outstanding stability stems from the hollow structure and OTS shell, which not only provide Pt with a protective shield against active site coverage, but also enhance competitive adsorption to benzene. Furthermore, DFT simulations unveil that the hydrophobic OTS shell enhances water resistance, consequently facilitates the oxidative degradation of contaminants at the active site. This work sheds light on novel strategies for the preservation of Pt by hydrophobic zeolite structures, as well as a deeper understanding of the elimination of aqueous VOCs.

Light triggers green recovery: Boosted biomethane production from ammonia-stressed anaerobic digestion through optimized illuminated bioreactor

Excess ammonia generated during anaerobic digestion (AD) often poses a great challenge on efficient waste-to-energy bioconversion, which requires feasible strategies to improve the performance. Herein, by response surface methodology (RSM), an innovative light-assisted bioreactor was designed for boosting ammonia-stressed AD. The proposed optimal light condition (225 W/m2 with 63 min/day) with incandescent lighting boosted CH4 yield (198 ± 15 mL CH4/g-DOCremoval), which was twofold of the dark reactor under ammonia stress. This light-induced enhancement was further found to be reliable and adaptive at different ammonia levels (2500–8000 mg/L), revealing its effectiveness for treating various ammonia-rich wastes. Additionally, the practical feasibility of sunlight utilization was confirmed by the similar performance obtained under simulated solar lighting (ultraviolet cut). Furthermore, the developed bioreactor exhibited a stable and superior conversion efficiency for 2 months, suggesting its sustainability for long-term operation. The mechanism insights revealed that light acted as stimulus on ammonia-stressed anaerobes, effectively regulated the enzyme activities, the functional microbiome, and the sludge properties to alleviate the ammonia inhibition. The critical coenzymes involved in methanogenic pathways (hydrogenotrophic and acetotrophic) were upregulated by light. Meanwhile, proper light stimulation diversified the ammonia-tolerant fermentative taxa (hydrolytic and acetogenic genera), which jointly collaborated with the enriched Methanosarcina. Under ammonia pressure, those enriched anaerobes aggregated in compact clusters which thermodynamically favored the sludge electroactivity and hydrophobicity, and assisted the syntrophic bioconversion. Therefore, the proposed bioreactor would be a promising technique to solve ammonia inhibition and achieve the sustainable waste-to-energy bioconversion with solar integration.

Exploring an electric-aid ozone decomposition mode to enhance water resistance over manganese oxide monolith catalyst under high humidity

In this work, a facile, green, and effective reaction mode of electric-aid ozone decomposition (EAOD) was developed over a manganese-based monolith catalyst for eliminating ozone under high humidity. The catalyst was prepared by directly growing α-MnO2 nanorods on Al honeycomb substrate (MnO2/Al) via a simple hydrothermal process, and the EAOD mode was performed just by connecting the MnO2/Al monolith catalyst with a DC power supply during ozone decomposition reaction. In the EAOD mode reaction, the MnO2/Al catalyst exhibited a stable ozone conversion efficiency of over 82 % and excellent stability over 720 min under a relative humidity of 90%, well beyond the performance of catalyst in the conventional ozone decomposition reaction without the help of electric aid. Here, the water evaporation by the external electric field generated from the EAOD mode hinders the competitive adsorption of water vapor on the active sites of MnO2/Al catalyst, consequently enhances its water resistance. Moreover, increasing input electric current of the DC power supply could further improve the catalytic activity and stability of the monolith catalyst for ozone decomposition in EAOD mode reaction.

Light and elevated temperature induced degradation and recovery of gallium-doped Czochralski-silicon solar cells

The fast-firing step commonly applied at the end of solar cell production lines is known to trigger light-induced degradation effects on solar cells made on different silicon materials. In this study, we examine degradation phenomena on high-efficiency solar cells with poly-Si passivating contacts made on Ga-doped Czochralski-grown silicon (Cz-Si) base material under one-sun illumination at elevated temperatures ranging from 80 to 160 °C. The extent of degradation is demonstrated to increase with the applied temperature up to 140 °C. Above 140 °C, the degradation extent decreases with increasing temperature. The degradation of the energy conversion efficiency can be ascribed foremost to a reduction of the short-circuit current and the fill factor and to a lesser extent to a reduction of the open-circuit voltage. The extent of degradation at 140 °C amounts to 0.4%abs of the initial conversion efficiency of 22.1% compared to 0.15%abs at 80 °C. The extent of the efficiency degradation in the examined solar cells is significantly lower (by a factor of ~ 5) compared to solar cells made on B-doped Cz-Si wafers. Importantly, through prolonged illumination at elevated temperatures (e.g. 5 h, 1 sun, 140 °C), an improvement of the conversion efficiency by up to 0.2%abs compared to the initial value is achievable in combination with a permanent regeneration resulting in long-term stable conversion efficiencies above 22%.

Modeling V̇o2 on-kinetics based on intensity-dependent delayed adjustment and loss of efficiency (DALE).

This study presents and evaluates a new mathematical model of V̇o2 on-kinetics, with the following properties: 1) a progressively slower primary phase following the size-principle of motor unit recruitment, explaining the delayed V̇o2 steady state seen in the heavy exercise intensity domain, and 2) a severe-domain slow component modeled as a time-dependent decrease in efficiency. Breath-by-breath V̇o2 measurements from eight subjects performing step cycling transitions, in the moderate, heavy, and severe exercise domains, were fitted to the conventional three-phase model and the new model. Model performance was evaluated with a residual analysis and by comparing Bayesian (BIC) and corrected Akaike (AICc) information criteria. The residual analysis showed no systematic deviations, except perhaps for the initial part of the primary phase. BIC favored the new model, being 9.3 (SD 7.1) lower than the conventional model whereas AICc was similar between models. Compared with the conventional three-phase model, the proposed model distinguishes between the kinetic adaptations in the heavy and severe domains by predicting a delayed steady-state V̇o2 in the heavy and no steady-state V̇o2 in the severe domain. This allows to determine when stable oxygen costs of exercise are attainable and it also represents a first step in defining time-dependent oxygen costs when stable energy conversion efficiency is not attainable.NEW & NOTEWORTHY We propose and assess a new minimalistic integrated model for the V̇o2 on-kinetics, inspired by the currently available best evidence of the underlying mechanisms. We show that the model provides a similar fit as the conventionally used three-phase model, even though a stricter data fitting method is used for the proposed model. The proposed model clarifies misconceptions related to the V̇o2 slow component's behavior, by clearly predicting that steady-state V̇o2 is attainable in the moderate and heavy exercise intensity domains. Furthermore, the model opens new possibilities for assessing oxygen cost during severe intensity exercise without the fallible assumption of time-constant energy-conversion efficiency.

A Solvothermal Synthetic Environmental Design for High‐Performance SnSe‐Based Thermoelectric Materials

AbstractSnSe is challenging to use in thermoelectric devices due to difficulties in simultaneously optimizing its thermoelectric and mechanical properties. Here, the authors show a unique solvothermal synthetic environmental design to fabricate super‐large and micro/nanoporous Sn0.965Se microplates by using CrCl3. Cl− ions to trigger Sn‐vacancy formation and optimize the hole concentration to ≈3 × 1019 cm−3, while the as‐formed Cr(OH)3 colloidal precipitations act as “templates” to achieve micro/nanoporous features, leading to low lattice thermal conductivity of ≈0.2 W m−1 K−1 in the as‐sintered polycrystal, contributing to a high ZT of ≈2.4 at 823 K and an average ZT of ≈1.1. Of particular note, the polycrystal exhibits high hardness (≈2.26 GPa) and compression strength (≈109 MPa), strengthened by grain refinement and vacancy‐induced lattice distortions and dislocations; while a single‐leg device provides a stable output power (>100 mW) and conversion efficiency of ≈10% by a temperature difference of 425 K, indicating great potential for applying to practical thermoelectric devices.

Smart PdH@MnO2 Yolk-Shell Nanostructures for Spatiotemporally Synchronous Targeted Hydrogen Delivery and Oxygen-Elevated Phototherapy of Melanoma.

Hydrogen therapy, an emerging therapeutic strategy, has recently attracted much attention in anticancer medicine. Evidence suggests that hydrogen (H2) can selectively reduce intratumoral overexpressed hydroxyl radicals (•OH) to break the redox homeostasis and thereby lead to redox stress and cell damage. However, the inability to achieve stable hydrogen storage and efficient hydrogen delivery hinders the development of hydrogen therapy. Furthermore, oxygen (O2) deficiency in the tumor microenvironment (TME) and the electron-hole separation inefficiency in photosensitizers have severely limited the efficacy of photodynamic therapy (PDT). Herein, a smart PdH@MnO2/Ce6@HA (PHMCH) yolk-shell nanoplatform is designed to surmount these challenges. PdH tetrahedrons combine stable hydrogen storage and high photothermal conversion efficiency of palladium (Pd) nanomaterials with near-infrared-controlled hydrogen release. Subsequently, the narrow bandgap semiconductor manganese dioxide (MnO2) and the photosensitizer chlorin e6 (Ce6) are introduced into the PHMCH nanoplatform. Upon irradiation, the staggered energy band edges in heterogeneous materials composed of MnO2 and Ce6 can efficiently facilitate electron-hole separation for increasing singlet oxygen (1O2). Moreover, MnO2 nanoshells generate O2 in TME for ameliorating hypoxia and further improving O2-dependent PDT. Finally, the hyaluronic acid-modified PHMCH nanoplatform shows negligible cytotoxicity and selectively targets CD44-overexpressing melanoma cells. The synergistic antitumor performance of the H2-mediated gas therapy combined with photothermal and enhanced PDT can explore more possibilities for the design of gas-mediated cancer therapy.

Flexible MXene-based Janus porous fibrous membranes for sustainable solar-driven desalination and emulsions separation

Sustainable solar energy driven seawater desalination technology is currently deemed as a promising pathway to overcome the shortage of freshwater resources, but solar water evaporation material suffers from serious salt-fouling, low freshwater yield, and poor long-term performance in seawater. Herein, a Janus photothermal porous fibrous membrane, composed of hydrophobic MXene/Poly(dimethylsiloxane) coatings and a hydrophilic polylactic acid/TiO2 nanofluids porous fibrous membrane, was prepared. During the solar-driven seawater desalination process, the hydrophilic fibrous membrane, functioned as salt-rejection barrier, induced by TiO2 nanofluids and transport seawater to the surface through its microporous channels; the MXene/PDMS coatings acted as a photothermal layer and generated localized heat at the water-vapor interface upon light irradiation. The solar-thermal test results show that, the Janus porous fibrous membrane displays stable solar-thermal conversion efficiency of 60%, freshwater yield of 1 kg m-2 h-1 and low ion concentration (≤1 ppm) under 1 sun irradiation in direct contact mode, which is superior to other literatures reported. With synergistic effect of TiO2 nanofluids and MXene, the Janus fibrous membrane exhibits a high salt rejection rate of 99.95%, and antibacterial activity as high as of 100%. Notably, benefiting from opposite wettability of Janus porous fibrous membrane, the as-prepared membranes also display excellent separation flux and high separation accuracy (>99.95%) in various surfactant-stabilized oil/water emulsions. It is anticipated that this versatility of Janus porous fibrous membrane has excellent photothermal conversion capability and separation properties, making it have great application potential in using sustainable solar energy to collect freshwater from seawater, medical service wastewater and other application in environmental protection.

Expanded graphite/paraffin/silica phase change composites with high thermal conductivity and low permeability prepared by the solid-state wet grinding method

In this study, expanded graphite (EG)/paraffin (PA)/silica (SiO2) composite phase change materials (PCM), with good thermal conductivity and impermeability, were fabricated for potential applications in solar energy. The EG-PA was first prepared by vacuum adsorption and then encapsulated by SiO2 through solid-phase wet grinding in the presence of sodium silicate. Our results show that the EG-PA-SiO2 composite have optimal properties when the mass ratio of raw material is PA: sodium silicate: H2O = 1:9:2:8. The latent heat of melting of the EG-PA-SiO2 composite prepared at this mass ratio is 106.2 J/g. The core material loss ratio, after washing with petroleum ether, is 4.79%. The thermal conductivity is 2.053 W/m·K, which is 8.5 times higher than that of pure paraffin wax, and the melt permeability is 9.35% after 120 min at 60 °C. Under simulated sunlight, the time required for the composite material to change from 30 °C to 65 °C is reduced by 70.78% compared to PA and the heat absorption and release times are nearly unchanged under multiple cycles. These results indicate that the material has a stable photothermal conversion efficiency.

Producing cold from heat with aluminum carboxylate-based metal-organic frameworks

Worldwide cooling energy demands will increase by four times by 2050. Thermally driven cooling technology is an alternative solution to electric heat pumps in removing hazardous refrigerants and harnessing renewables and waste heat. We highlight the advantages of water-stable microporous aluminum-carboxylate-based metal-organic frameworks, or Al-MOFs, as sorbents in the application of producing cold from heat. Here, we synthesize the Al-MOFs with green and scalable processes, which are prerequisites for exploring various industrial and civil applications. A proof-of-concept full-scale adsorption chiller with different Al-MOFs is built up with optimized configurations derived from various characterization techniques. The tested Al-MOFs achieve thermal efficiency above 0.6 and specific cooling power over 1 kW/kg in typical cooling scenarios. Notably, when solar thermal energy is used as the heat source in an outdoor validation, Al-MOFs are weather-resilient solutions that exhibit a stable energy conversion efficiency under fluctuating operating conditions (ambient temperature and solar irradiation).

An NIR-Triggered Au Nanocage Used for Photo-Thermo Therapy of Chronic Wound in Diabetic Rats Through Bacterial Membrane Destruction and Skin Cell Mitochondrial Protection.

Bacterial infection and its severe oxidative stress reaction will cause damage to skin cell mitochondria, resulting in long-lasting wound healing and great pain to patients. Thus, delayed wound healing in diabetic patients with Staphylococcus aureus infection is a principal challenge worldwide. Therefore, novel biomaterials with multifunction of bacterial membrane destruction and skin cell mitochondrial protection are urgently needed to be developed to address this challenge. In this work, novel gold cage (AuNCs) modified with epigallocatechin gallate (EGCG) were prepared to treat delayed diabetic wounds. The results showed that Au-EGCG had a high and stable photothermal conversion efficiency under near-infrared irradiation, and the scavenging rate of Au-EGCG for S. aureus could reach 95%. The production of large amounts of reactive oxygen species (ROS) leads to the disruption of bacterial membranes, inducing bacterial lysis and apoptosis. Meanwhile, Au-EGCG fused into hydrogel (Au-EGCG@H) promoted the migration and proliferation of human umbilical cord endothelial cells, reduced cellular mitochondrial damage and oxidative stress in the presence of infection, and significantly increased the basic fibroblast growth factor expression and vascular endothelial growth factor. In addition, animal studies showed that wound closure was 97.2% after 12 days of treatment, and the healing of chronic diabetic wounds was significantly accelerated. Au-EGCG nanoplatforms were successfully prepared to promote cell migration and angiogenesis in diabetic rats while removing S. aureus, reducing oxidative stress in cells, and restoring impaired mitochondrial function. Au-EGCG provides an effective, biocompatible, and multifunctional therapeutic strategy for chronic diabetic wounds.