Aerogels, macroscopic assemblies of low-dimensional nanomaterials in three-dimensional space, serve as a critical bridge to translate the extraordinary physicochemical properties of such nanoscale building blocks into practical macroscopic applications. However, their highly exposed reaction surfaces render them susceptible to drastic chemical and multiphase interfacial fluctuations during synthesis, hindering uniform, efficient nanoscale-to-mesoscale design and synthesis, thus limiting broader practical use. Herein, we report a solid-acid-mediated interfacial slow-release regulation strategy for silica aerogel hydrophobization, enabling 10-times faster ambient drying synthesis [diameter >3 cm, thickness similar to 1 cm, peak transmittance 96% between 380 and 760 nm, <14 h vs >145 h (hours) for state-ofthe-art strategy] of centimeter-scale monoliths. In-situ Fourier transform infrared, CT characterizations and molecular dynamics simulations reveal that local acid concentration regulation ensures uniform hydrophobic group grafting and preserves the integrity of the aerogel network. Aerogels exhibit ultralow thermal conductivity (0.034 W/m & centerdot; K at 50 degrees C) and high compressive strength (806 kPa at complete failure). A solar-thermal device based on the aerogels achieves 165 degrees C heat-collection temperature and 79.5 W/m(2) power density under 1 kW/m(2) solar radiation, outperforming most reported photothermalthermoelectric devices under equivalent conditions. This work establishes a conceptually-new interfacial regulation paradigm for construction of high-performance inorganic aerogels and other low dimensional inorganic materials.

The discovery of pressure-induced high temperature superconductivity in the bilayer nickelate La_3Ni_2O_7 has raised the question of how its spin-density-wave (SDW) state evolves toward the superconducting regime. Here, we report a systematic electronic Raman study of La_3Ni_2O_7 single crystals under hydrostatic pressures up to 16.51 GPa. Both the SDW gap energy and the transition temperature T_SDW show an overall increase with pressure, while the dimensionless coupling ratio 2Δ_SDW/(k_BT_SDW) remains constant around ∼7.5, indicating a robust strong-coupling character of SDW state. At the same time, the Raman SDW peak broadens as pressure is applied, indicating a gradual weakening of long-range SDW order. These results reveal an unusual pressure evolution in which the SDW energy scale is enhanced while the SDW state becomes progressively less coherent, providing spectroscopic constraints on the magnetic correlations relevant to superconductivity in bilayer nickelates.

Direct selective conversion of methane into high value-added chemical products has long attracted attention in both industry and academia. The production of C2 oxygenates is especially challenging owing to the requirement for both C-H activation and C-C coupling. Here we report a boron nanosheet-supported Cu single atom with Cu-B4 sites (Cu-SAs/B), which can effectively catalyse the conversion of methane to acetic acid with 97% selectivity and a high activity of 221.3 mmol gCu-1 h-1 without the addition of CO. In situ X-ray absorption fine structure analysis reveals that Cu single atoms undergo reversible 'switching' to Cu4 clusters under CH4 oxidation conditions, enabling efficient C-H activation and C-C coupling. The switching behaviour is triggered by the presence of H2O2, and the coupling occurs between CH3* and CHO* intermediates formed on Cu single atoms and Cu clusters, respectively, as confirmed by in situ spectroscopic techniques. These findings provide a proof of concept for designing highly effective methane oxidation catalysts based on switchable nanocatalysts.

For decades, γ-N2 has been known to exist at very low temperatures and pressures, located in a tiny area of the nitrogen phase diagram. Recently, it was shown that γ-N2 occupies most of the P–T space usually associated with molecular phases such as δ, ɛ, and ζ, and that it plays a pivotal role in shaping nitrogen’s phase diagram. Using powder synchrotron X-ray diffraction, Raman and infrared spectroscopy, and density function theory calculations, we have investigated the structural and optical properties of γ-N2 in a wide P–T range. The combined X-ray diffraction and infrared spectroscopy results unequivocally demonstrate that γ-N2 adopts the monoclinic (P21/c space group) configuration with two N2 molecules per unit cell. It appears that the γ-N2 is structurally closely related to θ-N2, leading to both phases having very similar Raman signatures. Additionally, the Raman spectroscopy reveals a vibrational mode intensity resonance effect in both phases, caused by a strong vibrational coupling between the isotopic 15N14N and 14N2 vibrational excitations.

Simultaneously exciting phonon polaritons with distinct topologies in a single crystal at a unified excitation frequency offers a route to combine their different propagation characteristics. In this work, by selecting an appropriate crystal plane in Lu2SiO5, we investigated the gold-disk-patterned Lu2SiO5 crystal using scattering-type scanning near-field optical microscopy (s-SNOM) and achieved the simultaneous excitation of two phonon polaritons with hyperbolic and elliptic-like isofrequency contours at a single frequency. The hyperbolic and elliptic-like phonon polaritons are launched by the fabricated gold disks and the SNOM tip, respectively. The propagation wave of the elliptic-like phonon polaritons is reflected by the gold disks and then is detected by the SNOM tip again, resulting in a momentum that is twice the intrinsic momentum, which is further confirmed by attenuated total reflection spectroscopy measurements using a coupled ZnSe prism for excitation. Our finding significantly enriches the anisotropic propagation behavior of phonon polariton in a single crystal.

Low-perittivity (1-x)Ca3(BO3)2-xTiO2 (CBTO, x = 0-0.25) ceramics were fabricated via cold sintering. Phase composition was confirmed by XRD. The effects of TiO2 doping on the dielectric properties and temperature stability (tau f) were systematically investigated. Guided by lattice dynamics, phonon characteristics were probed using Raman and FTIR spectroscopy. Eight Raman-active and ten infrared-active modes were identified. A four-parameter semi-quantum model successfully extracted the intrinsic dielectric parameters, revealing that vibrations related to Ca2+ (Mode 4) contributed most significantly (21.89% to epsilon(r), 32% to loss). TiO2 addition effectively tuned tau f from -39.89 & times; 10-6 degrees C- 1 towards zero. This comprehensive phonon analysis established a clear structure-property relationship. The optimal composition (x = 0.20) exhibited a balanced performance: epsilon(r) = 10.56, Q & times; f = 10,896 GHz, and tau f = -6.58 & times; 10-6 degrees C- 1. To demonstrate practical utility, a 5G microstrip patch antenna was designed using this ceramic. The antenna resonated at 9.97 GHz with excellent impedance matching (S11 = -49.56 dB) and a peak gain of 6.39 dBi. These results confirm CBTO ceramics as a promising candidate for temperature-stable, high-frequency applications. (c) 2026 The Authors. Published by Elsevier B.V. on behalf of The Chinese Ceramic Society. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

In this study, SrSn(BO3)2-x wt% LiF microwave ceramics were successfully prepared at 950 degrees C via conventional solid-state sintering. Phase composition and microstructure were characterized by XRD and SEM, respectively. XRD confirmed the absence of secondary phases, while SEM revealed that the x = 3.0 wt% sample exhibited the most uniform grain size and highest density. Lattice vibrational characteristics were analyzed using Raman and FTIR spectroscopy. With increasing LiF content, the Ag mode shifted to higher wavenumbers, indicating shortened B-O bond lengths and reduced polarizability, leading to a decrease in the dielectric constant. The FWHM of the v2 mode reflected structural ordering and showed a negative correlation with Q & times; f. Seven FTIR vibrational modes were identified, and intrinsic dielectric properties were evaluated using the four-parameter semiquantum model to elucidate dielectric response mechanisms. Among them, mode 2 contributed most significantly to both the dielectric constant (33.33%) and dielectric loss (53.84%). Results indicate that SrSn(BO3)2-3 wt% LiF ceramics exhibited excellent microwave dielectric properties: epsilon r = 5.17, Q & times; f = 42 211 GHz (15.72 GHz) and tau f = -42.31 ppm degrees C-1. A microstrip patch antenna simulated using this ceramic as a substrate showed a center frequency of 12.0 GHz, return loss (S11) of -40.0 dB, and peak gain of 6.86 dBi, demonstrating strong application potential in microwave communication systems.

The bilayer nickelate superconductor La3Ni2O7 undergoes a density wave transition near 150 K that has attracted intensive scrutiny, yet its microscopic origin remains elusive. Here we report polarization-resolved electronic Raman scattering measurements on high-quality single crystals of La3Ni2O7. Below 150 K, we observe a pronounced, symmetry-dependent redistribution of spectral weight in B1g and B2g channels, consistent with the formation of spin-density-wave (SDW) gaps. Quantitative analysis reveals momentum-selective SDW gap amplitudes, with intermediate-to-strong coupling near X/Y points of the Brillouin zone and weaker coupling along the diagonal direction, indicating an unconventional SDW driven by anisotropic electronic correlations. Our results establish the electronic character of the SDW in La3Ni2O7, and provide a microscopic foundation for understanding the emergence of high-temperature superconductivity under pressure in nickelates.

Photocatalytic dinitrogen conversion through artificial nitrogenase is known as the holy grail for ammonia production. The effective utilization of photogenerated charge carriers is essential for optimizing its photocatalytic performance, yet underlying charge carrier separation and dinitrogen conversion mechanisms steering such a reaction on a catalyst, especially a nitrogen-containing system, remains underdeveloped. Here, by integrating rutile TiO2 with N-doped graphene, complete functions of natural nitrogenase are duplicated for overall photocatalytic dinitrogen conversion to generate ammonia and nitric oxide. More importantly, we demonstrate that N-dopant sites can serve as nitrogen carriers for sustaining the dinitrogen conversion via the N-cycle pathway, where the nitrogen element is detached from N-doped graphene and consumed for ammonia generation and then replenished by the atmospheric dinitrogen during the reaction. Our work not only offers a viable way to imitate the natural nitrogenase system, but also shines light on the dinitrogen conversion pathway for N-containing photocatalysts.

Ca3(BO3)2 microwave dielectric ceramics with space group R-3c (#167) were prepared by cold sintering, and their properties were systematically investigated. Phonon density of state diagrams for the Ca3(BO3)2 lattice were obtained based on first-principles calculations to provide a more comprehensive understanding of the lattice vibrational properties of the material. Raman scattering and infrared reflectance spectroscopy were employed to investigate the lattice vibrational characteristics, identifying two types of vibrational modes: internal modes associated with the planar bending and symmetric stretching vibrations of the [BO3] group, and external modes linked to the vibrations of the [CaO6] octahedron. The intrinsic dielectric properties were determined by fitting the experimental data using a four-parameter semi-quantum model. The results demonstrate that the dielectric properties of Ca3(BO3)2 ceramics are primarily influenced by the external vibrational modes. The sample under 800 MPa exhibits optimal dielectric performance, with a dielectric constant (εr) of 5.95, a quality factor (Q × f) of 11,836 GHz, and a temperature coefficient of resonant frequency (τf) of −39.89 ppm/°C. A simulation of this Ca3(BO3)2 sample as a dielectric substrate was conducted using HFSS to fabricate a microstrip patch antenna operating at 14.97 GHz, which exhibits a return loss (S11) of −25.5 dB and a gain of 7.15 dBi.

The thickness constraint of thin crystals imposes spatial limitations on phonon polaritons (PhPs) and thus significantly affects their properties. In this work, we theoretically study the PhPs in different type hyperbolic bands of thin beta-gallium oxide (beta-Ga2O3) crystals and find that the volume-confined phonon polaritons (v-PhPs) can be launched. The v-PhPs excited by the light frequency corresponding to type I-perpendicular to hyperbolic bands can propagate along in-plane direction which is impossible in bulk crystal. Furthermore, the modes coupling results in a "petal-like" isofrequency curve for the v-PhPs excited by the light frequency of type II parallel to hyperbolic bands in thin beta-Ga2O3, enabling the polariton waves to propagate along mutually orthogonal directions. This feature renders the thin crystal as a dynamic beamsplitter that can be activated by selecting an appropriate incident wavelength, thereby facilitating the manipulation of light or heat propagation. These findings provide a promising avenue for applications in nanophotonic and heat conduction applications.

The precise fabrication and regulation of the stable catalysts with desired performance still challengeable for single atom catalysts. Here, the Ru single atoms with different coordination environment in Ni3FeN lattice are synthesized and studied as a typical case over alkaline methanol electrooxidation. The Ni3FeN with buried Ru atoms in subsurface lattice (Ni3FeN-Ruburied) exhibits high selectivity and Faradaic efficiency of methanol to formate conversion. Meanwhile, operando spectroscopies reveal that the Ni3FeN-Ruburied exhibits an optimized adsorption of reactants along with an inhibited surface structural reconstruction. Additional theoretical simulations demonstrate that the Ni3FeN-Ruburied displays a regulated local electronic states of surface metal atoms with an optimized adsorption of reactants and reduced energy barrier of potential determining step. This work not only reports a high-efficient catalyst for methanol to formate conversion in alkaline condition, but also offers the insight into the rational design of single atom catalysts with more accessible surficial active sites. Fine turning the local configuration of single atoms into substrate is challenging. Here, the authors report that burying single atoms into subsurface lattice of substrate can stimulate more surficial active sites and thus promote the overall catalytic performance in methanol electrooxidation.

The electrochemical nitrate-to-ammonia reduction reaction (NO 3 RR) offers a sustainable route for carbon-neutral chemical synthesis, while the intricate multi-electron/proton transfer processes and unstable intermediates pose significant challenges in attaining high selectivity and efficiency. This study demonstrates a Co, Fe bimetallic conjugated metal organic frameworks (CoFe-cMOFs) that enable efficient NO 3 RR via an unconventional [6 + 2] electron-transfer tandem pathway. Unlike the traditional [2 + 6] tandem pathway, the Fe sites predominantly reduce NO 3− to *NH 2 OH intermediate, which subsequently spills over onto the Co sites for further protonation. This unconventional tandem pathway effectively avoids the release of NO 2− and guarantees selective NH 3 production. The CoFe-cMOFs achieve 94.3% NH 3 -producing Faradaic efficiency with a yield rate of 14.1 mg h −1 cm −2 in neutral electrolyte. The Zn-NO 3 − battery prototype incorporating CoFe-cMOFs exhibits 3.6 mW cm −2 peak power density with stable NH 3 production. This work proposes a mechanistic breakthrough in tandem pathway regulation for selective electrochemical ammonia synthesis.

Single-atom catalysts (SACs) challenge conventional multi-site catalysis by enabling oxidative processes like H2 and CO oxidation. However, we herein present that the completely isolated SACs are inactive, while spatially adjacent single-atom pairs (interatomic distance < 4 Å) work cooperatively as the true active sites. Rh atomic densities were precisely tuned between 0.1 wt%-17.5 wt% via graphene quantum dots confinement. Mathematical modeling quantifies the scaling of active pairs versus electrochemical performance, rationalizing activity dependence on atomic proximity. 18O isotope labeling and in situ synchrotron infrared spectroscopy analyses identified a new reaction mechanism, with water bifunctional dissociation enabled on sub-4 Å Rh pairs, and acts as the rate-determining step towards both CO and H2 oxidation. While H2O enters the COOR process as a reactant and enters the HOR process as a molecular catalyst. Our findings redefine bifunctional catalysis, merging single-atom precision with nanoparticle-like cooperativity for efficient energy conversion systems.

Electrocatalytic ammonia synthesis through the nitrate to ammonia (NRA) technique is of energy and environmental sustainability for the nitrogen cycle. Nevertheless, the nitrite (*NO2) intermediate may desorb, which would reduce the productivity of ammonia and the of Faradaic efficiency. Here, a heterostructured electrocatalyst consisting of amorphous CuO and crystalline CeO2 is prepared for efficient NH3 production through the interface tandem [2 + 6]-electron electrocatalysis approach. In alkaline medium, the NH3 yield and Faradaic efficiency reach 8.6 mg h 1 mgcat 1 and 96 %, respectively. As evidenced by the in situ experiments and theoretical calculations, the amorphous@crystalline interfacial local unsaturated Cu-Ce bimetallic site configuration endows the heterostructured electrocatalyst with strong *NO2 adsorption abilities and sufficient *H supply, which synergistically catalyze NH3 production through the [2 + 6]-electron NRA process. Furthermore, the Zn-NO3 battery devices, constructed with amorphous-CuO@crystalline-CeO2 as electrode materials, demonstrate outstanding application results. This work suggests an achievable route for promoting the NRA activity, enabling simultaneous ammonia production, electricity generation, and wastewater treatment, and holds great potential for the development of new heterostructured electrocatalysts for NH3 production.

In this work, strontium tin borate [SrSn(BO3)2, SSBO] microwave dielectric ceramics (MWDCs) were synthesized using the traditional solid-state sintering method at different sintering temperatures. The formation of phase-pure SSBO ceramics was determined by the Rietveld refinement of X-ray diffraction patterns, and the sample sintered at 1150 °C showed the densest micro-morphology. Lattice vibrational spectroscopy was used to interpret the intrinsic properties to develop structure–property relationships of the SSBO MWDCs. Seven distinct Raman-active vibrational modes were observed in the Raman spectra, and nine distinct vibrational modes were identified in the infrared spectra. The intrinsic dielectric properties were fitted and simulated by the four-parameter semi-quantum model according to the far-infrared reflection spectra of the ceramics. The dielectric responses of the SSBO ceramics were revealed based on their Raman and infrared spectra, and the microstructural origins of the dielectric responses were also clarified. Therefore, the correlations between the crystal structures and the dielectric properties of the SSBO ceramics were created from the Raman phonon modes. The B–O bond lengths and the Ag mode shifts were closely related to the dielectric constants. The full-widths at half maximum of the v2 modes were positively correlated with the quality factor values. The SSBO ceramic sintered at 1150 °C exhibited the best dielectric properties of εr = 5.42, Q × f = 32,618 GHz (f = 15.68 GHz), and τf = − 48.28 ppm/°C. This indicates that this sample was an ultra-low-permittivity MWDC with great potential for 5G applications. Simulation of this SSBO sample as a dielectric substrate was conducted using HFSS to fabricate a microstrip patch antenna capable of operating at 5.17 GHz, which exhibited a return loss (S11) of − 23.4 dB and a gain of 6.58 dBi.

The synergistic Cu0-Cuδ+ sites are found as the active sites for NH3 synthesis through nitrate electroreduction reaction, but still face significant challenges in stabilizing the Cuδ+ due to its self-reduction. Here we propose an Ohmic contact interface engineering strategy by loading copper nano-islands on indium hydroxide nanocubes. Attributed to the lower work function of Cu than that of In(OH)3 with n-type semiconductor nature, the electrons in Cu can transfer unimpededly to In(OH)3 at the interface of Ohmic junction, triggering and stabilizing polarized Cu0-Cuδ+ active sites. Cu@In(OH)3 sustains both high NH3 yield rate (4.28 mmol h-1 mgcat.-1) and Faradaic efficiency (97.35%) at -0.6 V vs. RHE, while maintaining stability for at least 120 h under an Ampere-level of 800 mA cm-2. Such Ohmic contact interface engineering approach allows for simultaneously constructing and stabilizing the Cu0-Cuδ+ for the electrosynthesis of ammonia, as well as other value-added chemicals relying on above active sites.

The general understanding on the reaction path is that the electrocatalytic N 2 reduction follows either individual associative alternating or distal pathways, where efficient N 2 activation and selective NH 3 production are very challenging. Herein, an unconventional “alternating‐distal” pathway was achieved by shifting the “*NHNH 2 →*NH 2 NH 2 ” to “*NHNH 2 →*NH + NH 3 ” step to boost NH 3 synthesis with an amorphous CeMnO x electrocatalyst. In this unconventional process, N 2 activation was realized through π back donation on the Mn site, while the Mn/Ce dual active sites could regulate the intermediate configurations to avoid the nitrogen‐containing by‐product formation. Such “alternating‐distal” pathway was affirmed by in situ spectroscopic analyses and theoretical calculations. In a neutral media, an average ammonia production rate of 82.8 µg h −1 mg −1 and an outstanding Faradaic efficiency of 37.3% were attained. This work validated an unconventional mechanism in electrocatalytic ammonia synthesis, which might be extended to other catalytic process with multiple possible reaction paths.

Electrochemical nitrate reduction emerges as a promising approach for ammonia generation; however, its efficiency is hindered by the sluggish hydrogenation of nitrogen‐containing intermediates and limited active hydrogen supply at constant applied potentials. Driven by the pulsed electrocatalysis, in this work, efficient nitrate‐to‐ammonia conversion is realized by facilitating *NOOH formation and balancing *H supply on a Janus Cu@Co/NC electrocatalyst. In detail, the Cu sites could activate NO 3 − at low overpotentials, while the Co sites could facilitate *NOOH formation with sufficient *H provided by the Co sites at high overpotentials. Promoted by the pulsed electrocatalysis technique, a maximum Faradaic efficiency of 98.32% with NH 3 yield rate of 12.75 mg h −1 mg cat −1 is attained, and the scaled‐up pulsed electrosynthesis at industrial current densities is also achieved. This work underlines the feasibility of pulsed electrolysis for regulating intermediate hydrogenation, offering a promising approach for the synthesis of ammonia or other important chemicals.