High-Entropy Photothermal Materials

High-performance, salt-resistant, and stable wood-based solar evaporator equipped with sodium alginate-based functional skin

Harnessing renewable solar energy for photothermal evaporation and seawater desalination holds significant potential for alleviating freshwater scarcity. However, evaporators reported recently often suffer from limitations in environmental compatibility, salt resistance, and stability. Herein, we report a green and straightforward approach to fabricate a dual-layer solar evaporator (STF-wood) by equipping wood-based materials with a sodium alginate-based photothermal skin. The functional skin, synthesized through the chelation of tannic acid (TA), sodium alginate (SA), and Fe3+, not only exhibits excellent photothermal conversion efficiency but also forms a dense network that restricts the movement of free water, thereby enhancing the localized heat effect. Moreover, the positively charged surface of the skin can prevent the passage of salt ions through the Donnan effect, demonstrating superior salt resistance. STF-wood is capable of operating stably in seawater with an evaporation rate of 1.92 kg m-2 h-1 and maintains a similar rate even after undergoing 5-hour ultrasonic treatment. This work presents a sustainable and efficient solution to compensate for the shortcomings of environmental compatibility and operational stability for solar evaporator.

Orbital Matching Mechanism-Guided Synthesis of Cu-Based Single Atom Alloys for Acidic CO2 Electroreduction

Recent advancements in alloy catalysis have yield novel materials with tailored functionalities. Among these, Cu-based single-atom alloy (SAA) catalysts have attracted significant attention in catalytic applications for their unique electronic structure and geometric ensemble effects. However, selecting alloying atoms with robust dispersion stability on the Cu substrate is challenging, and has mostly been practiced empirically. The fundamental bottleneck is that the microscopic mechanism that governs the dispersion stability is unclear, and a comprehensive approach for designing Cu-based SAA systems with simultaneous dispersion stability and high catalytic activity is still missing. Here, combining theory and experiment, a simple yet intuitive d-p orbital matching mechanism is discovered for rapid assessment of the atomic dispersion stability of Cu-based SAAs, exhibiting its universality and extensibility for screening effective SAAs across binary, ternary and multivariant systems. The catalytic selectivity of the newly designed SAAs is demonstrated in a prototype reaction-acidic CO2 electroreduction, where all SAAs achieve single-carbon product selectivity exceeding 70%, with Sb1Cu reaching a peak CO faradaic efficiency of 99.73 ± 2.5% at 200 mA cm-2. This work establishes the fundamental design principles for Cu-based SAAs with excellent dispersion stability and selectivity, and will boost the development of ultrahigh-performance SAAs for advanced applications such as electrocatalysis.

Ferritin-Inspired Encapsulation and Stabilization of Gold Nanoclusters for High-Performance Photothermal Conversion

Gold nanoclusters (AuNCs) are highly promising for applications in photothermal conversion due to their exceptional surface area and optical properties. However, their high surface energy often leads to aggregation, compromising stability and performance. To address this, we developed a ferritin-inspired covalent organic cage with a near-enclosed cavity to physically stabilize AuNCs. This superphane cage coordinates with Au3⁺ ions, forming highly stable and uniform AuNCs upon reduction. The encapsulated AuNCs exhibit broad absorption (250-2500 nm) and achieve remarkable photothermal conversion efficiency of 92.8% under 808 nm laser irradiation. At low power densities (0.5 W/cm2), temperatures reach 150 °C, and under one-sun illumination (1 kW/m2), the solar-to-vapor generation efficiency reaches 95.1%, with a water evaporation rate of 2.35 kg m-2 h-1. Even after 20 seawater desalination cycles, the system maintains a stable evaporation rate of 2.24 kg m-2 h-1, demonstrating excellent salt tolerance and durability. This ferritin-inspired strategy offers a robust platform for enhancing the stability and performance of AuNCs, advancing sustainable energy and water purification technologies.

Mitigating Strain Localization via Stabilized Phase Boundaries for Strengthening Multi-Principal Element Alloys

Multi-principal element alloys (MPEA) demonstrate exceptional stability during rapid solidification, making them ideal candidates for additive manufacturing and other high-design-flexibility techniques. Unexpectedly, MPEA failure often mimics that of conventional metals, with strain localization along phase or grain boundaries leading to typical crack initiation. Most strategies aim at reducing strain localization either suppress the formation of high-energy sites or dissipate energy at crack tips to enhance toughness, rarely achieving a synergy of both. Inspired by the microstructure of mouse enamel, nanoscale body-centered cubic (BCC) and face-centered cubic (FCC) phases into MPEAs are introduced, stabilized at phase boundaries to provide ample plastic space for dislocation-mediated deformation. This approach overcomes the local hardening limitations of nanoscale alloys and harmonizes traditional toughening mechanisms-such as crack deflection, blocking, and bridging-to mitigate strain localization. These mechanisms impart the alloy with ultra-high tensile strength (≈1458.1 MPa) and ductility (≈21.2%) without requiring heat treatment. Atomic calculations reveal that partial atomic plane migration drives continuous dislocation transfer across phases. This study uncovers fundamental but latent mechanical mechanisms in MPEAs, advancing understanding of ultra-strong bioinspired alloys.

Unlocking Methane Generation via Photo-Thermal-Coupled CO2 Hydrogenation by Integrating FeNiCrMnCo Multicomponent Alloy with GaN Nanowires

The exploration of a noble-metal-free photo-thermal-coupled catalytic architecture plays a vital role in solar-driven conversion of carbon dioxide (CO2) into high-value fuels and chemicals. In this study, FeNiCrMnCo multicomponent alloy (MCA) is integrated with GaN nanowires (NW's) for photo-thermal-coupled catalytic CO2 methanation. The MCA/GaN NW's nanohybrid demonstrates a considerable methane production rate of 199 mmol∙g-1∙h-1 with an impressive selectivity of 93% under white light irradiation of 3 W∙cm-2 at 290 °C by external heating. The turnover number approaches 20,160 mole CH4 per mole of MCA over a continuous operation period of 120 h, showcasing remarkable stability. Mechanistic investigations reveal that the unique MCA provides a flexible platform for tailoring the electronic and catalytic properties to optimize the adsorption and activation of CO₂ and H₂, thus leading to efficient and selective CO₂ methanation. This study presents an industry-friendly architecture for photo-thermal-coupled CO2 hydrogenation into high-value fuels and chemicals by coupling a noble-metal-free multicomponent alloy with GaN NWs, paving the way for advancements in sustainable energy conversion through CO2 utilization.

Green Syngas from Photothermal Catalytic Cellulose Steam Reforming on Ni/SiO2 Nanocatalysts: Synergy of La3+ Promotion and Ni-O Photoactivation

Replacing fossil fuels by renewable biomass enables green syngas production in an effort to achieve carbon neutrality and sustainable circular processes. Here, an inexpensive catalyst of Ni nanoparticles supported on SiO2 modified by La3+ (Ni/La0.10-S) is presented, exhibiting exceptional H2 and CO production rates (4051.4 and 2467.8 mmol gcatalyst -1 h-1, respectively) with 7.7% light-to-fuel efficiency in cellulose steam reforming (SR), merely under focused illumination. Excellent performance is mainly attributed to photothermal catalysis resulting from the strong solar absorption and high photothermal conversion by the Ni nanoparticles. The mitigation of tar and char formation significantly benefits from the H2O involvement in the reaction, which is substantially improved by La3+ addition enhancing H2O sorption. Remarkably, the illumination exerts mere photoactivation during reaction, which is primarily attributed to the pronounced activation of Ni─O bonds at the catalyst surface. Particularly, the photoactivation of the Ni-O-La moieties, in combination with O species replenishment by H2O, makes Ni/La0.10-S superior to Ni/SiO2. The synergy of La3+ promotion and Ni-O photoactivation poses a promising strategy for efficient photothermal catalytic cellulose SR to green syngas.

Utilization of Stable and Efficient High-Entropy (Ni0.2Zn0.2Mg0.2Cu0.2Co0.2)Al2O4 Catalyst with Polyvalent Transition Metals to Boost Peroxymonosulfate Activation toward Pollutant Degradation

A polyacrylamide gel method has been used to synthesize a variety of polyvalent-transition-metal-doped Ni position of high entropy spinel oxides (Ni0.2Zn0.2Mg0.2Cu0.2Co0.2)Al2O4-800 °C (A2) on the basis of NiAl2O4, and the catalytic activity of A2 is studied under the synergistic action of peroxymonosulfate (PMS) activation and simulated sunlight. The A2 containing polyvalent transition metals (Ni2+, Cu2+, and Co2+) can effectively activate PMS and efficiently degrade levofloxacin (LEV) and tetracycline hydrochloride (TCH) under simulated sunlight irradiation. After 90 min of light exposure, the degradation percentages of LEV (50 mg L-1) and TCH (100 mg L-1) degrade by the A2/PMS/vis system reach 87.0% and 90.2%, respectively. The superoxide radicals, photoinduced holes, and singlet oxides dominate the catalytic process, while hydroxyl radicals and sulfate radicals play only a small role. The adsorption energy and charge density difference between different systems and PMS are calculated by density functional theory, and the activation efficiency of PMS is studied by combining with the change of the length of the O─O bond of the PMS after adsorption. The catalytic mechanism of A2/PMS/vis system is proposed, which provides a new idea and method for the study of high entropy oxides in the field of catalysis.

Advancements in high-entropy materials for electromagnetic wave absorption

Widespread electromagnetic (EM) interference and pollution have become major issues due to the rapid advancement of fifth-generation (5G) wireless communication technology and devices. Recent advances in high-entropy (HE) materials have opened new opportunities for exploring EM wave absorption abilities to address the issues. The lattice distortion effect of structures, the synergistic effect of multi-element components, and multiple dielectric/magnetic loss mechanisms can offer extensive possibilities for optimizing the balance between impedance matching and attenuation ability, resulting in superior EM wave absorption performance. This review gives a comprehensive review on the recent progress of HE materials for EM wave absorption. We begin with the fundamentals of EM wave absorption materials and the superiority of HE absorbers. Discussions of advanced synthetic methods, in-depth characterization techniques, and electronic properties, especially with regard to regulatable electronic structures through band engineering of HE materials are highlighted. This review also covers current research advancements in a wide variety of HE materials for EM wave absorption, including HE alloys, HE ceramics (mainly HE oxides, carbides, and borides), and other novel HE systems. Finally, insights into future directions for the further development of high-performance HE EM wave absorbers are provided.

Fabrication of Polydopamine-Coated High-Entropy MXene Nanosheets for Targeted Photothermal Anticancer Therapy

Transition metal carbides, nitrides, and carbonitrides (MXenes) have emerged as a promising class of 2D materials that can be used for various applications. Recently, a new form of high-entropy MXenes has been reported, which contains an increased number of elemental species that can increase the configurational entropy and reduce the Gibbs free energy. The unique structure and composition lead to a range of intriguing and tunable characteristics. Herein, the fabrication of high-entropy MXene TiVNbMoC3Tx (T = surface terminations) with a layer of polydopamine is reported, followed by immobilization of a phthalocyanine-based fluorophore for imaging and the peptide sequence QRHKPREGGGSC for targeting the epidermal growth factor receptor (EGFR) overexpressed in cancer cells. The resulting nanocomposite exhibits high biocompatibility and superior photothermal property. Upon laser irradiation at 808 nm, the light-to-heat conversion efficiency is up to 56.1%, which is significantly higher than that of conventional 2D materials. In vitro studies show that these nanosheets could be internalized selectively into EGFR-positive cancer cells and effectively eliminate these cells mainly through photothermal-induced apoptosis. Using 4T1 tumor-bearing mice as an animal model, the nanosheets could accumulate at the tumor and effectively eradicate the tumor upon laser irradiation without causing noticeable adverse effects to the mice.

General Synthesis of High-Entropy Oxides and Carbon-Supported High-Entropy Oxides by Mechanochemistry

High-entropy oxides (HEOs) have been receiving a lot of attention due to their excellent properties. However, current common methods for preparing HEOs usually involve high-temperature processes. The development of green synthesis techniques remains an important issue. Carbon-supported HEOs have shown excellent performance in electrochemical energy storage in recent years. Crucially, the traditional methods cannot synthesize carbon-supported HEOs under N2 or air atmospheres. Toward this end, a universal method for preparing carbon-supported HEOs was proposed. During this process, without high-temperature post-treatment, high-entropy LaMnO3 could be synthesized in 2 hours using the mechanical ball-milling method. Furthermore, this method was universal and has been proved in the synthesis of a series of HEOs such as PrVO3, SmVO3, and MgAl2O4. The LaMnO3 species synthesized by this method exhibit excellent catalytic performance in CO combustion and could maintain a conversion rate of over 97 % for 350 hours. Subsequently, carbon-supported HEOs could be obtained with 0.5 hours of additional ball-milling, offering significant advantages over traditional methods. This process provides a potential method to synthesize carbon-supported HEOs.

Atomic-Level Electric Polarization in Entropy-Driven Perovskites for Boosting Dielectric Response

Dielectric oxides with robust relaxation responses are fundamental for electronic devices utilized in energy absorption, conversion, and storage. However, the structural origins governing the dielectric response remain elusive due to the involvement of atomically complex compositional and structural environments. Herein, configurational entropy is introduced as a regulatory factor to precisely control the structural heterogeneity in representative perovskite dielectric oxides. Through advanced structural and electric field visualization studies, a novel quantitative relationship is established between atomic-level structural disorder-induced electric field polarization and macroscopic dielectric properties. The results indicate that the degree of atomic delocalization in perovskite oxides exhibits a near-parabolic trend with increasing entropy, reaching a maximum in medium-entropy perovskite. Correspondingly, the atomic electric field vectors display significant asymmetrical distribution, thus greatly enhancing angstrom-scale electric field polarization. Then, it is experimentally proven that entropy-driven electric polarization can improve the dielectric relaxation behavior characterized by broader frequency and stronger intensity of electromagnetic energy absorption, with improvements of approximately 160% and 413% compared to structurally homogeneous control. This study unveils the quantitative correlation between angstrom-scale electric field polarization and dielectric response in perovskite oxides, offering a novel perspective for exploring the structure-property relationship in dielectric materials.

High-Entropy Oxides: Pioneering the Future of Multifunctional Materials

The high-entropy concept affords an effective method to design and construct customized materials with desired characteristics for specific applications. Extending this concept to metal oxides, high-entropy oxides (HEOs) can be fabricated, and the synergistic elemental interactions result in the four core effects, i.e., the high-entropy effect, sluggish-diffusion effect, severe-lattice-distortion effect, and cocktail effect. All these effects greatly enhance the functionalities of this vast material family, surpassing conventional low- and medium-entropy metal oxides. For instance, the high phase stability, excellent electrochemical performance, and fast ionic conductivity make HEOs one of the hot next-generation candidate materials for electrochemical energy conversion and storage devices. Significantly, the extraordinary mechanical, electrical, optical, thermal, and magnetic properties of HEOs are very attractive for applications beyond catalysts and batteries, such as electronic devices, optic equipment, and thermal barrier coatings. This review will overview the entropy-stabilized composition and structure of HEOs, followed by a comprehensive introduction to the electrical, optical, thermal, and magnetic properties. Then, several typical applications, i.e., transistor, memristor, artificial synapse, transparent glass, photodetector, light absorber and emitter, thermal barrier coating, and cooling pigment, are synoptically presented to show the broad application prospect of HEOs. Lastly, the intelligence-guided design and high-throughput screening of HEOs are briefly introduced to point out future development trends, which will become powerful tools to realize the customized design and synthesis of HEOs with optimal composition, structure, and performance for specific applications.

High-Entropy Boride HfZrTiTaMoB: Promising Materials for Solar Selective Absorption Coatings in Photothermal Applications

High-entropy borides (HEBs), as a category of high-entropy materials, exhibit remarkable thermal stability, a broad compositional range, and finely tuned electronic structures, leading to an excellent functional performance. Despite these advantages, their application in photothermal materials has rarely been reported. Herein, we employ a HEB target with multiple transition-metal elements to develop solar selective absorption coatings (SSACs) with simple and scalable bilayer structures for photothermal applications. The performance of these coatings is enhanced by designing different antireflective layers. The designed SSACs, both stainless steel (SS)/HEB/Al2O3 and SS/HEB/Si3N4, exhibit high absorptivity and low thermal emittance (α/ε = 90.0%/8.6% and 91.6%/8.6% at 82 °C). Thermal stability tests show that the absorbers could withstand annealing at 500 °C for 5 h, while maintaining a good optical performance. Long-term thermal stability tests indicate that the coatings retained good spectral selectivity after annealing at 400 °C for 100 h. Notably, the coatings demonstrate advanced photothermal conversion efficiencies of 88.3% and 89.9%, respectively, at 400 °C under 100 sun. In practical simulated solar irradiation experiments, the absorber achieves temperatures of about 85 °C under 1 sun, surpassing the performance of commercial nonselective absorbing coatings. Additionally, the absorbers maintained a stable photothermal performance through six on-off cycle experiments. In summary, the designed SSACs based on HEBs exhibit excellent optical properties and efficient photothermal conversion at moderate temperatures. This study highlights the significant benefits and potential advancements in solar energy collection offered by HEB-based SSACs.

High-Entropy Materials for Application: Electricity, Magnetism, and Optics

High-entropy materials (HEMs) have recently emerged as a prominent research focus in materials science, gaining considerable attention because of their complex composition and exceptional properties. These materials typically comprise five or more elements mixed approximately in equal atomic ratios. The resultant high-entropy effects, lattice distortions, slow diffusion, and cocktail effects contribute to their unique physical, chemical, and optical properties. This study reviews the electrical, magnetic, and optical properties of HEMs and explores their potential applications. Additionally, it discusses the theoretical calculation methods and preparation techniques for HEMs, thereby offering insights and prospects for their future development.

PdMoPtCoNi High Entropy Nanoalloy with d Electron Self-Complementation-Induced Multisite Synergistic Effect for Efficient Nanozyme Catalysis

Engineering multimetallic nanocatalysts with the entropy-mediated strategy to reduce reaction activation energy is regarded as an innovative and effective approach to facilitate efficient heterogeneous catalysis. Accordingly, conformational entropy-driven high-entropy alloys (HEAs) are emerging as a promising candidate to settle the catalytic efficiency limitations of nanozymes, attributed to their versatile active site compositions and synergistic effects. As proof of the high-entropy nanozymes (HEzymes) concept, elaborate PdMoPtCoNi HEA nanowires (NWs) with abundant active sites and tuned electronic structures, exhibiting peroxidase-mimicking activity comparable to that of natural horseradish peroxidase are reported. Density functional theory calculations demonstrate that the enhanced electron abundance of HEA NWs near the Fermi level (EF) is facilitated via the self-complementation effect among the diverse transition metal sites, thereby boosting the electron transfer efficiency at the catalytic interface through the cocktail effect. Subsequently, the HEzymes are integrated with a portable electronic device that utilizes Internet of Things-driven signal conversion and wireless transmission functions for point-of-care diagnosis to validate their applicability in digital biosensing of urinary biomarkers. The proposed HEzymes underscore significant potential in enhancing nanozymes catalysis through tunable electronic structures and synergistic effects, paving the way for reformative advancements in nano-bio analysis.

Optimized Photothermal Conversion Ability through Interband Transitions in FeCoNiCrMn High-Entropy-Alloy Nanoparticles

High-entropy-alloy nanoparticles (HEA-NPs) composed of 3d transition metallic elements have attracted intensive attention in photothermal conversion regions due to their d-d interband transitions (IBTs). However, the effect arising from the unbalanced elemental ratio still needs more focus. In this work, FeCoNiCrMn HEA-NPs with different elemental ratios among Cr and Mn have been employed to clarify the impact of different composed elements on the optical absorption and photothermal conversion performance. It can be recognized that the unbalanced elemental ratio of HEA-NPs can reduce the photothermal performance. Density functional theory calculation demonstrated that d-d IBTs can be changed by the different composed element ratios, resulting in a number of insufficient filling regions around the Fermi level (±4 eV). As a result, the HEA-NPs (FeCoNiCr0.75Mn0.25) with a balanced elemental ratio exhibit the highest surface temperature of 97.6 °C under 1 sun irradiation, and the evaporation rate and energy conversion efficiency could reach 2.13 kg·m-2·h-1 and 93%, respectively, demonstrating effective solar steam generation behavior.