Materials Horizons最新文献

In the realm of sensing, piezoionic systems have emerged as innovative tools for perceiving tactile sensations through mechanical-to-ionic transduction, mimicking biological signal production and transmission. To date, the biomimetic transduction mechanism and strategies for engineering the transduction efficiency remain not fully understood and underutilized. This review provides the fundamentals of mechanical-to-ionic transduction for efficient self-powered sensing, identifying the most crucial structural and operating parameters governing the generation of a transient signal output with respect to the migration and redistribution of ions upon mechanical stimulation. It also examines the recent strategies for efficiently converting mechanical keystrokes into electrical signals through performance-driven structural design, thereby maximizing piezoionic voltage generation. This involves engineering ion transport and fluid flow through porosity, microphase separation, conductive pathways and structural gradients. With respect to piezoionic effect-based applications, this review highlights the promising potential of polymeric, ionic materials in soft wearable electronics, ionic skins, tissue engineering, biointerfaces and energy harvesting.

The electrocatalytic nitrate (NO₃^-) reduction reaction to ammonia (NH₃) offers a sustainable pathway for wastewater remediation and distributed NH₃ synthesis, presenting a capable alternative to the energy-intensive Haber-Bosch process. Copper (Cu)- and cobalt (Co)-based catalysts are among the most promising for this reaction due to their favourable electronic structure for NO₃^- activation and cost-effectiveness. However, their propensity for rapid deactivation caused by the strong adsorption of intermediates like *NO that poison active sites remains a primary impediment to high selectivity and stability. This review comprehensively investigates recent breakthroughs in overcoming this limitation through advanced catalyst design strategies specifically for Cu- and Co-based systems. In detail, the protocols were critically examined to regulate intermediate adsorption strength via facet engineering, oxidation state modulation, single-atom dispersion and construction of bimetallic catalysts that provide synergistic *H species to enhance hydrogenation kinetics through optimization of the d band center of Cu and Co. Furthermore, innovative tandem catalysis systems and paired electrolysis configurations are also explored to couple the NO₃^- reduction reaction with alternative oxidation reactions (AORs) to drastically improve energy efficiency and economic viability. Therefore, by synthesizing these design principles this review aims to guide the development of next-generation, high-performance and durable Cu- and Co-based electrocatalysts for scalable sustainable nitrogen management.

Crosslinked functional polymers exhibit exceptional mechanical and chemical properties critical for applications spanning biomedical engineering, advanced adhesives, and self-healing materials. However, challenges in recycling, either due to irreversible crosslinks or, in the case of covalent adaptable networks (CANs), limited solid-state plasticity that typically requires catalysts, significantly restrict sustainability. To address these limitations, we present a novel water-mediated polymerization strategy inspired by the radical-generating mechanism of the Maillard reaction, utilizing maltose as both an initiator and a functional side group in a simple, catalyst-free, aqueous reaction with acrylamide (AAm). This mild, one-pot reaction occurs below 100 °C, forming adaptively functionalized supramolecular networks (AFSNs) that form supramolecular networks through hydrogen bonding and display dynamic imine linkages to the maltose side chains supporting self-healing and re-shaping. These elastomers are characterized by impressive mechanical strength (up to 5 MPa tensile strength), high elongation (up to 1000%), notable fracture energy (36 kJ m⁻²), robust adhesive performance (up to 4.8 MPa), and rapid self-healing capability at room temperature. Crucially, the elastomer's supramolecular network can be fully and repeatedly dissolved and reprocessed using only water, preserving mechanical integrity without chemical degradation. This sustainable approach provides a practical solution for synthesizing and recycling high-performance crosslinked materials while eliminating environmental hazards, guiding the future development of green polymer chemistry and functional material design.

Conventional strategies for enhancing the mechanical robustness of thermoplastic polyurethane elastomers (TPUs) rely on hard-segment engineering, such as introducing dynamic covalent/noncovalent bonds or optimizing chain extenders, yet overlook the critical role of soft segments in governing microphase separation. Here, we present a soft-segment-regulated design that leverages crystallizable polyols to synergize hierarchical hydrogen bonding, tunable microphase separation, and strain-induced crystallization (SIC), achieving excellent mechanical performance. Among them, PU-PTMEG exhibits exceptional mechanical properties, including a tensile strength of 75.6 MPa, a toughness of 337.4 MJ m^-3, and a fracture energy of 131.6 kJ mol^-1-values that surpass those of many metals and alloys. Furthermore, its true fracture stress reaches 1.03 GPa, comparable to that of spider silk, while its toughness is approximately 2.3 times higher, demonstrating a remarkable combination of strength and toughness. The dynamic yet dense hydrogen bond network, strategically balanced in both strength and reversibility, enables efficient energy dissipation during deformation, while the SIC activated by aligned soft segments facilitates elastomer self-reinforcement. Finally, by combining the antibacterial properties endowed by intrinsic acylhydrazine groups (bacterial survival rate <20%) and the introduction of rigid polyurethane foam as an acoustic impedance modifier, high-contrast ultrasound imaging of TPU wires has been successfully achieved.

The development of highly efficient and stable oxygen evolution reaction (OER) electrocatalysts represents a critical challenge for advancing water splitting hydrogen production technology. In this work, we report a novel defect engineering strategy through synergistic Fe/Al doping and Co vacancy construction in a CoMOF precursor, achieving remarkable performance enhancement after electrochemical reconstruction. Density functional theory (DFT) calculations elucidate the cooperative mechanism of Fe/Al dopants and Co vacancies, which positions the Gibbs free energy of O (ΔG_O*) exactly at the center of ΔG_OH* and ΔG_OOH*, thereby dramatically decreasing the catalytic overpotential and boosting the catalytic activity. Experimental characterization studies conclusively demonstrate the successful electronic structure modulation achieved through this triple-defect (Fe/Al doping and Co vacancy) synergistic strategy, which exhibits exceptional electrocatalytic performance with an ultralow overpotential of 229 mV at 10 mA cm^-2. The concerted effects of these engineered defects not only remarkably enhance the intrinsic activity through optimized electronic configurations but also significantly improve charge transfer kinetics. This innovative defect-engineering paradigm establishes a universal methodology for the rational design of high-performance electrocatalysts across diverse electrochemical energy conversion systems.

The complex and varied relationship found in intermolecular interactions within the photo-active layers plays a decisive role in determining the photovoltaic energy conversion and overall device performance of organic solar cells (OSCs). Among different approaches, the ternary blend strategy serves as an effective technique to control the morphology within the active layer in OSCs. In this work, PM6:L8-BO is used as the main host system (binary) while the fullerene molecules PC₆₁BM and PCBC6 are introduced to form ternary OSCs. The results highlight the important role of fullerenes in enhancing the performance of binary non-fullerene acceptor-based cells by suppressing trap-assisted recombination and optimizing the active layer morphology. The improved film phase microstructure, enabled by fullerene derivatives with higher lowest unoccupied molecular orbital (LUMO) energy levels in comparison to the host acceptor (L8-BO), facilitates more efficient charge collection and reduced non-radiative recombination. This results in an increase in the fill factor (FF) and open circuit voltage (V_oc) in the ternary OSCs. Consequently, power conversion efficiencies (PCEs) of binary OSCs were increased from 17.28% to 18.10% and 18.38% for the PC₆₁BM- and PCBC6-based ternary OSCs, respectively. Furthermore, the addition of the fullerene molecules in the active layer provided the devices with enhanced long-term photo and thermal stability. The ternary OSCs demonstrated degradation pathways distinct from those of binary cells (ISOS-L1-I and ISOS-D2-I protocols), as identified through in situ ultraviolet-visible (UV-Vis) absorption and Raman spectroscopy. Molecular dynamics (MD) simulations, for the first time, reveal the significant role of fullerene molecules as morphology regulators in non-fullerene acceptor (NFA)-based systems. Their presence ensures improved dispersion of blend components and promotes more uniform and isotropic thermal and mechanical behaviour. Finally, mini-modules with active areas of 3.8 cm² were fabricated, achieving PCEs of 12.90%, 13.32%, and 13.70% for the binary and ternary cells using PC₆₁BM-and PCBC6-based ternary cells, respectively. Our results demonstrate that regulation of the morphology of the photo-active layer in OSCs through fullerene incorporation reduces the non-radiative energy loss pathways, enabling high-efficiency, stable and scalable OSCs.

Electrocatalytic reduction of CO₂ into CO holds great promise for addressing environmental challenges and industrial needs. However, the practical implementation is hindered by the hydrogen evolution reaction (HER), which competes for electrons and reduces the selectivity of the CO₂ reduction reaction (CO₂RR). Here, we have proposed a novel strategy to enhance CO₂RR selectivity using an ordered structure from a mass transport perspective for the first time. Ag nanowires (NWs) were selected as model catalysts and assembled into an ordered array. The ordered structure of Ag NWs induces an ordered micro electric field that crucially regulates the kinetic mass transports of both the CO₂RR and HER. This micro electric field is demonstrated to promote the preferential accumulation of CO₂ on the catalyst surface while concurrently repelling H₂O molecules. This dual action, which enriches the desired reactant and depletes the source for the competing reaction, tilts the balance in favor of CO₂ reduction over the HER, thereby enhancing selectivity towards CO production. Therefore, the ordered Ag NW arrays demonstrated highly efficient CO₂ electroreduction to CO, resulting in an impressive 97.3% faradaic efficiency (FE) of CO at a current density of 100 mA cm^-2, significantly outperforming their disordered counterparts. This innovative approach not only inspires the design of structural assembly in electrocatalysts from a mass transport perspective but also provides fundamental insights into the relationship between the ordering of structured catalysts and their CO₂RR performance.

In the context of metamaterials, decoupled access to the four constitutive parameters (permittivity, permeability, mass density, and bulk modulus) using a single architecture can unlock substantial design freedom, thereby enabling possibilities for a wide range of electromagnetic and acoustic wave manipulation applications. Herein, we propose a modular replaceable design paradigm for hybrid metamaterials to independently control electromagnetic and acoustic properties within a unified metamaterial unit cell. By arranging printed circuit board traces into an interleaved, meandering lattice, the proposed hybrid metamaterial can simultaneously generate microwave resonances for tuning of negative permittivity and permeability while acting as rigid acoustic boundaries of space-coiled air channels to produce negative mass density and bulk modulus. This hybrid metamaterial is further experimentally demonstrated to realise the simultaneous negative refraction of electromagnetic and acoustic waves. Our design paradigm represents a promising pathway toward advanced hybrid metamaterials, potentially enabling unprecedented functionalities in wave manipulation, sensing, and integrated electromagnetic-acoustic devices.

Intermetallic nanocatalysts are pivotal for advancing energy conversion and storage technologies. However, their industrial-scale synthesis is fundamentally hindered by the difficulty of maintaining precise compositional and structural control. Here, we introduce a universal phase-engineering strategy, actualized through a continuous roll-flow radiative heating platform that enables the one-step, scalable, and controllable synthesis of highly ordered intermetallic nanocatalysts. This innovative technique demonstrates remarkable versatility, rendering precise fabrication of intermetallic nanocrystals across a vast compositional landscape. Crucially, by modulating key kinetic parameters during synthesis, we achieve precise control over ordering arrangement with fine-tuning of catalytic performance. As a proof of concept, we demonstrate the scalable and sustainable synthesis of nickel-iron intermetallic (Ni₃Fe) nanocatalysts with a predominant L1₂-ordered crystal structure for efficient alkaline water splitting. The resulting catalyst exhibits exceptional electrocatalytic activity, reaching a current density of 10 mA cm^-2 at a low overpotential of 200.2 mV, a performance that rivals the commercial iridium dioxide (IrO₂) benchmark (199.2 mV). Moreover, it shows outstanding long-term durability, with 99.9% current retention over 140 hours and negligible metal leaching. A comprehensive techno-economic evaluation reveals that the hydrogen production cost is strongly dependent on current density, projecting a highly competitive H₂ price as low as $2.33 kg^-1 at 1.0 A cm^-2. This work is expected to provide advanced technology for scalable, sustainable, and continuous manufacturing of intermetallic nanocrystals for economical water splitting.

Modification of graphitic carbon nitride (g-C₃N₄) with semiconductor nanomaterials has been widely investigated as an effective method to enhance its photocatalytic activity. However, the construction of efficient g-C₃N₄-based heterojunction photocatalysts via an environmentally benign method remains critical. Herein, a two-dimensional (2D) few-layered MoS₂/S-doped g-C₃N₄ hierarchical heterojunction was successfully synthesized by a simple strategy via combining small molecule-assisted liquid exfoliation, calcination and hydrothermal strategy, which was subsequently utilized for photocatalytic formaldehyde removal. The evaluation of the photocatalytic degradation reaction showed that the as-prepared 2D/2D MoS₂/S-doped g-C₃N₄ photocatalysts exhibited superior photocatalytic activity compared to pristine g-C₃N₄ and S-doped g-C₃N₄ alone, which was attributed to the intimate interface and rapid charge transfer pathways. This heterojunction structure suppresses the excited electron-hole pair recombination within g-C₃N₄, which optimally enhances the photodegradation activity owing to high electron-hole pair separation efficiency. The few-layer MoS₂ nanosheets play an irreplaceable role due to their unique molybdenum-sulfur atomic arrangement, thereby displaying the superior electronic properties of few-layer or even monolayer nanosheets, which make them an important transfer medium for photoexcited electrons. Meanwhile, S doping effectively modulates the band gap of g-C₃N₄ and introduces sufficient structural defects to inhibit electron-hole recombination. Moreover, the synthesis employs efficient and non-hazardous reagents, and the resulting catalysts exhibit outstanding stability and recyclability for pollutant degradation.