Tungsten diboride (WB_{2+x}) has been predicted to be a superhard material. It, however, has yet to be practically realized, because of its intrinsically low toughness, without involving favorable dislocation slip systems. Here, we report a viable strategy to effectively strengthen both the toughness and hardness of WB_{2+x} by introducing ordered atomic vacancies to increase dislocation mobility along certain directions. By doping with rhenium atoms, the ordered metal-vacancy pairs are revealed to occur extensively in the optimally doped sample with a composition of (W_{0.9}Re_{0.1})_{1-δ}B_{2+x} synthesized under high pressure. Such vacancy pairs are found to mainly reside in the {210} and {102} planes, along which the long-range dislocations are kinetically favored for improving its toughness and plasticity to achieve a load-invariant superhardness of ∼40  GPa. In addition, its thermal stability is drastically promoted and rivals that of cubic boron nitride (cBN). These discoveries not only experimentally identify a superhard material but also provide powerful insights into how the mechanical properties of transition-metal diborides can be improved by tailoring atomic deficiencies.

The relationship between the pseudogap and superconductivity remains a central puzzle in the physics of cuprates. Hydrostatic pressure provides a clean tuning parameter free from chemical disorder, yet probing the microscopic energy scales of these phases under compression has remained experimentally challenging. Here, we utilize ultrafast optical spectroscopy to construct the high-pressure phase diagram of the underdoped cuprate Bi_2Sr_2CaCu_2O_8+δ up to 37 GPa. Our results reveal a striking dichotomy within the pseudogap state: while the onset temperature T^* rises monotonically with pressure, the energy gap Δ_PG is continuously suppressed. In contrast, the critical temperature T_c and the superconducting gap Δ_SC trace a correlated dome-like trajectory, demonstrating that superconductivity evolves independently from the pseudogap. Furthermore, an abrupt collapse of the gap ratio 2Δ_SC/k_BT_c near 8 GPa marks a pressure-driven dimensional crossover, quenching two-dimensional phase fluctuations to stabilize global three-dimensional coherence. Upon reaching 37 GPa, the superconducting condensate is completely quenched into an insulating-like state. By resolving the extended phase evolution, our findings disentangle the pseudogap and superconducting orders, establishing a rigorous experimental basis for the pairing mechanism of high-temperature superconductivity.

Hydrogen peroxide (H2O2) is a versatile and environmentally benign oxidizing agent with widespread applications in chemical manufacturing, disinfection, and environmental remediation, particularly in water treatment and pulp bleaching. The photocatalytic two-electron oxygen reduction reaction (2e(-) ORR) presents a promising sustainable pathway for H2O2 production, enabling the direct conversion of solar energy into chemical energy. Among various catalytic materials, covalent organic frameworks (COFs) have garnered considerable interest as metal-free, organic semiconductor photocatalysts. Their highly ordered crystalline and porous architectures, along with their tunable molecular structures, provide an ideal platform for facilitating mass transport and promoting the efficient separation and migration of photogenerated charge carriers. A growing number of COF-based materials are now being explored for photocatalytic H2O2 generation. This review systematically examines the relationship between the structural features of COFs and their photocatalytic performance, offering insights into design strategies for enhancing their activity. Special emphasis is placed on the role of specific structural regulation in enabling efficient and sustainable H2O2 production. It provides a comprehensive analysis of how intricate design elements, including linkage regulation (Schiff base, polyimide, irreversible bonds), organic building block engineering (pi-conjugated systems, donor-acceptor architectures), morphological control (1D/2D/3D nanostructures), post-synthetic modification (linkage conversion, pore-wall functionalization, metal anchoring, protonation), and heterojunction construction (Type II, Z-scheme, S-scheme systems). Furthermore, the review discusses both the notable advancements and existing challenges in this emerging field. By critically assessing current limitations and future opportunities, this review aims to outline prospective research directions and provide a foundational guide for the rational design and application of COF-based photocatalysts, thereby supporting progress toward sustainable solar-driven chemical synthesis.

We report high-pressure single-crystal X-ray diffraction measurements on the quasi-one-dimensional (Q1D) antiferromagnetic metal KMn6Bi5 up to 12.5 GPa, revealing the detailed pressure evolution of its atomic coordination environment. We find that the lattice exhibits pronounced anisotropic compressibility-the relative changes in the a and b lattice parameters reach a/a0=0.91 and b/b0 = 0.94 at 12.5 GPa-and a distinct structural anomaly emerges near 11 GPa without any symmetry-breaking. Detailed structural analysis further uncovers an anomalous hardening of the Mn nanotubes between 5 and 11 GPa, followed by a configuration optimization of the Mn/Bi nanotubes around 11 GPa. These features correlate closely with the reported pressure-temperature phase diagram of KMn6Bi5 and compare favorably with the chemical pressure effects induced by substituting K with Na, Rb, or Cs. Our findings provide key microscopic insights into how coordination environment modulation governs the stability of electronic orders in low-dimensional systems.

Leveraging size-tunable luminescence and surface-engineered functionalities, quantum dots (QDs) enable ultrasensitive environmental monitoring while minimizing ecological footprints. This comprehensive review highlights the diverse classes of fluorescent QDs, including carbon, silicon, copper, and doped variants, as well as their transformative applications in agricultural production and food safety. Possessing their tunable fluorescence, exceptional stability, and biocompatibility, QDs drive innovations across both domains. In sustainable agriculture, CQDs serve as nano-priming agents that enhance pigeon pea germination and root vitality, while silicon QDs function as foliar light fertilizers that boost lettuce biomass by matching chloroplast absorption spectra. Crucially, QDs antiviral platforms reduce the overuse of pesticides by suppressing viruses through RNA targeting, thereby curbing soil contamination. For food safety, copper QDs on graphdiyne nanosheets detect organophosphorus pesticides at ultralow concentrations (1 ng/mL), overcoming interference challenges. Integration of QDs with immunomagnetic separation enables visual quantification of E. coli O157:H7 (500 CFU/mL detection limit), and doped CQDs achieve rapid aflatoxin screening in dairy products (0.07 ng/mL) via fluorescence quenching. Future priorities include AI-optimized design-for-degradation of perovskite QDs, the development of heavy metal free QDs for soil remediation, and the integration of solar-powered QDs sensors for real-time tracking across supply chains. To translate these laboratory advances into field applications, establishing standardized validation protocols is crucial for positioning QDs as reliable keystones in planetary boundary-compliant food systems.

As an important member of metal nitrides, the rocksalt vanadium nitride (VN) shows an unusual coexistence of superconductivity and spin fluctuation, which provides a rare case for study of the interplay between these two exotic phenomena. However, due to the challenging sample synthesis its superconductive and magnetic properties have been sparsely explored, leading to many contradictory reports. Here we present a systematic study of VN based on high-quality single-crystal samples synthesized by a high-pressure method. Our results reveal that the material is a phonon-mediated type-II superconductor and exhibits weak magnetic response as potentially manifested by spin fluctuation that interacts weakly with superconductivity. Pressure enhances the electron-phonon coupling while it suppresses spin fluctuation, largely promoting its superconducting transition temperature (Tc) from 7.8 K at ambient pressure up to 12.8 K at similar to 93 GPa with a 64% increase. The discovery of this work offers insights into how the superconductivity can be influenced by spin fluctuation.

In crystalline materials, grain boundaries have been extensively studied and are acknowledged either as structural defects or as distinct phases, referred to as complexions. However, the nature of interfaces in amorphous systems, particularly whether amorphous-amorphous interfaces constitute separate phases and their structural characteristics, remains unresolved. In this study, we report a Pd40Ni40P20 bulk granular nanostructured glass (GNG) that exhibits an interfacial structural-compositional rearrangement. The GNG was fabricated by compacting glassy Pd40Ni40P20 nanoparticles with surface compositional segregation under a triaxial pressure of 8 GPa. The as-prepared GNG shows Pd40Ni40P20 nanograins with Ni-enriched interfacial regions. Upon heating, the anomalous structural-compositional rearrangement occurs specifically at the amorphous interfaces, manifested by a deep exothermic peak at a temperature TS below the glass transition temperature Tg. This structural-compositional rearrangement induces significant modifications in both compositional fluctuations and medium-range ordering, subsequently modifying the material’s mechanical properties. Whether amorphous-amorphous interfaces constitute separate phases requires clarification. This study reports a Pd40Ni40P20 bulk granular nanostructured glass with an interfacial structural-compositional rearrangement.

Transition-metal borides have emerged as promising candidates for potential superhard materials due to their remarkable mechanical properties, favorable synthesis conditions and diverse physical properties. However, achieving the requisite hardness for classification as superhard materials in transition-metal borides remains a significant challenge. In this study, we employed a multicomponent strategy to optimize electron band filling, investigating the thermodynamic stability and mechanical properties of ScxTa1_xB2 (0 <= x <= 1) transition-metal diborides. Calculations predicted Sc0.5Ta0.5B2 as the most promising composition, with its Fermi level located near the pseudogap, resulting in the lowest thermodynamic energy and superior mechanical properties. Experimentally, Sc0.5Ta0.5B2 was successfully synthesized under ambient pressure, achieving a hardness of 31.5 GPa under a 4.9 N load, the highest hardness reported for single-phase transition-metal borides. Additionally, Sc0.5Ta0.5B2 shows an electrical resistivity of 104.9 mu S2 & centerdot;cm at room temperature, indicating its excellent electrical conductivity. These findings provide critical insights for the design of novel superhard metal materials, achieved through electron filling modifications induced by multicomponent strategies. This approach expands the potential for developing cost-effective, superhard materials, with implications for advancing transition-metal diborides.

Perovskite‐type ternary nitrides with predicted exciting ferroelectricity and many other outstanding properties hold great promise to be an emerging class of advanced ferroelectrics for use in diverse technologically important devices. However, such nitride ferroelectrics have not yet been experimentally identified, mainly due to the challenging sample synthesis by traditional methods at ambient pressure. Here, we report the successful high‐pressure synthesis of a high‐quality ferroelectric nitride perovskite of CeTaN 3‐δ with nitrogen deficiency, adopting an orthorhombic Pmn 2 1 polar structure. This material is a semiconductor and exhibits switchable and robust electric polarization for producing ferroelectricity. Furthermore, a number of other extraordinary properties are also revealed in this nitride such as excellent mechanical properties and chemical inertness, which would make it practically useful for many device‐relevant applications and fundamentally important for the study of condensed‐matter physics.

CeSiI is a van der Waals heavy-fermion metal recently found to exhibit unconventional superconductivity near a pressure-induced antiferromagnetic quantum critical point (QCP) at Pc =6 GPa. Here, we report a comprehensive single-crystal X-ray diffraction study of CeSiI under high pressures up to 8.3 GPa at room temperature, revealing subtle structural responses that precede pressure-driven QCP. We find that the unit-cell volume decreases smoothly upon compression without showing any structural phase transition in the investigated pressure range. Intriguingly, we observe abrupt and concurrent anisotropic responses of the lattice parameters around Pc =6 GPa, i.e., the a-axis contracts while the c-axis enlongated suddenly, with the unit-cell volume smoothily varies with pressure. Structural refinements further show that these lattice anomalies primarily originate from changes of Ce-Ce and Ce-Si bond lengths, as well as a flattening of the inner honeycomb Si layer within the CeSiI monolayer around Pc. Our findings establish an interesting case linking pressure-driven electronic transition of QCP at low temperatures to incipient structural responses at room temperature, thereby providing fresh insight into the pressure-temperature phase diagram of CeSiI.

Exploring and synthesizing materials with new crystal structures provides an important route to discovering exotic quantum phenomena. However, materials with unconventional lattice geometries remain largely unexplored. Here, we report the discovery of a new vanadium-based material, Cs3V9Te13, featuring a Reuleaux-triangle-like lattice composed of interwoven triangular, square, and pentagonal motifs. Electrical transport, Hall, and magnetic measurements consistently reveal an anomaly near 48 K, and this feature shows little sensitivity to the applied magnetic field. Specific-heat measurements further confirm the phase transition at 48 K, while the relatively large Sommerfeld coefficient ( mJ & centerdot;mol-1 & centerdot;K-2) suggests strong electronic correlations in Cs3V9Te13. In addition, temperature-dependent X-ray diffraction results indicate no obvious structural change across 48 K. Taken together, these results suggest that the anomaly is not induced by a structural transition but may be associated with an electronic and/or magnetic phase transition. High-pressure transport measurements reveal a highly tunable electronic state in Cs3V9Te13, while first-principles calculations suggest electronic features reminiscent of kagome systems and an antiferromagnetic tendency that is progressively suppressed under pressure. These results demonstrate that this material, with its structurally novel Reuleaux-triangle-like lattice, serves as a new platform for exploring the interplay between nontrivial lattice geometry and emergent physical phenomena.

Photocatalytic H2O2 production via the two-electron oxygen reduction reaction (2e-ORR) represents a promising solar-to-chemical conversion pathway toward decarbonizing the chemical industry, offering a sustainable alternative to the energy-intensive anthraquinone process. However, its practical viability is constrained by sluggish charge carrier dynamics and insufficient active-site specificity in existing photocatalysts. Moving beyond conventional single-parameter optimization, this study introduces a dual electric field-mediated strategy that synergistically integrates atomic-scale boron (B)-induced polarization with macroscopic p-n junction engineering. By precisely doping B atoms into the NH2-MIL-125(Ti) framework (denoted B-NMT), an intrinsic polarization field is established, which electronically reconstructs the Ti-oxo clusters. This results in localized electron accumulation (+0.21 |e| per Ti site), transforming them into highly selective catalytic centers for the 2e-ORR. This B-tuned microenvironment stabilizes the critical *OOH intermediate, thereby lowering the reaction energy barrier and enhancing intrinsic activity. To address the persistent challenge of charge recombination, a p-n heterojunction is constructed by integrating p-type CuNb2O6 (CNO). The built-in interfacial field drives directional electron migration from CNO to the B-activated Ti sites of B-NMT, enabling efficient spatial separation photogenerated carriers. The dual-field synergy spanning atomic to micrometer scales achieves spatiotemporally regulated charge flow, simultaneously optimizing surface reaction kinetics and bulk charge transport. The resulting B-NMT/CNO heterostructure delivers a remarkable H2O2 production rate of 2537.38 mu mol & sdot;g-1 & sdot;h-1 under visible light, with an apparent quantum yield (AQY) of 7.9% at 420 nm. Density functional theory (DFT) calculations confirm that the B-induced charge localization facilitates O2 activation, while the junction-induced drift field overcomes diffusion-limited transport. By demonstrating that atomic-level coordination engineering and band-aligned heterostructuring could cooperatively reconfigure multi-step reaction landscapes, this work establishes a function-decoupled design paradigm for sustainable energy applications.

Enhancing the fracture toughness of diamond while preserving its hardness is a significant challenge. Most toughening strategies have primarily focused on modulating the internal microstructural units of diamonds, including adjustments to stacking sequences, faults, nanotwinning, and the incorporation of amorphous phases, collectively referred to as intrinsic toughening. Here, we introduce an extrinsic toughening strategy to develop an unparalleled tough diamond composite with complex and abundant sp 2 - sp 3 bonding interfaces, by incorporating highly dispersed multi-walled carbon nanotubes (MWCNTs) into the gaps of diamond grains to create a three-dimensional (3D) continuous MWCTNs network-toughen heterogeneous structure. The resultant composite exhibits a hardness of approximately 91.6 GPa and a fracture toughness of roughly 36.4 MPa·m 1/2 , which is six times higher than that of synthetic diamond and even surpasses that of tungsten alloys, surpassing the benefits achievable through intrinsic toughening alone. The remarkable toughening behavior can be attributed to the formation of numerous mixed sp 2 - sp 3 bonding interactions at the 3D continuous network MWCNTs/diamond interfaces, which facilitate efficient energy dissipation. Simultaneously, a 3D diamond framework with robust D-D bonding was built, safeguarding against hardness loss from MWCNT incorporation. Our 3D continuous network heterogeneous structure design provides an effective approach for enhancing the fracture toughness of superhard materials, offering a new paradigm for the advanced composite ceramics.

Perovskite-type ternary nitrides with predicted exciting ferroelectricity and many other outstanding properties hold great promise to be an emerging class of advanced ferroelectrics for use in diverse technologically important devices. However, such nitride ferroelectrics have not yet been experimentally identified, mainly due to the challenging sample synthesis by traditional methods at ambient pressure. Here, we report the successful high-pressure synthesis of a high-quality ferroelectric nitride perovskite of CeTaN3-delta with nitrogen deficiency, adopting an orthorhombic Pmn21 polar structure. This material is a semiconductor and exhibits switchable and robust electric polarization for producing ferroelectricity. Furthermore, a number of other extraordinary properties are also revealed in this nitride such as excellent mechanical properties and chemical inertness, which would make it practically useful for many device-relevant applications and fundamentally important for the study of condensed-matter physics.

Ionic transport in oxides is generally frozen at cryogenic temperatures, where thermal energy lies far below typical cation-migration barriers. Neutron powder diffraction reveals progressive Fe/Mg redistribution between tetrahedral (A) and octahedral (B) sites in the spinel Mg0.5Fe0.5TiFeO4 upon cooling from 200 K to 5 K. A-site Fe occupancy increases toward near completion at 5 K within Rietveld resolution, while Ti remains on the B site. This exchange coincides with complex magnetic correlations rather than a classical thermally activated window. Low-temperature magnetostrictive volume changes indicate strong spin-lattice coupling, but do not identify magnetostriction as the sole thermodynamic driver. Room-temperature high-pressure X-ray diffraction produces the opposite occupancy trend, showing that volume contraction alone cannot explain the cryogenic site exchange. These results point to magneto-structural free-energy minimization as a plausible mechanism for unlocking cryogenic cation mobility in a correlated spinel oxide.

To address persistent challenge of charge recombination in semiconductor photocatalysis, we engineered an S-scheme heterojunction via covalent /3-ketoenamine bridges between zirconium-based MOFs and triazine-COFs (Zr-BTB-COF). This dual-functional system pioneered a "one-photon, two-value" strategy for simultaneous CO2-to-CO reduction and 4-methoxybenzyl alcohol-to-anisaldehyde oxidation, enabling solar-driven carbon refineries. Synergistic in-situ XPS analysis and density functional theory calculations unambiguously validated the S-scheme charge transfer mechanism. The covalent interface overcame lattice mismatch constraints while Fermi-level alignment generated an enhanced built-in electric field (9.8 times stronger than pristine Zr-BTB-NH2), achieving ultrafast charge separation. Low-energy carrier recombination through the /3-ketoenamine bridge preserved high-potential carriers (-1.61 V for CO2 reduction; +2.22 V for alcohol oxidation). Critically, this architecture reduced the activation energy barrier for the rate-limiting *COOH ->*CO step to Delta G = 0.65 eV, a 42% reduction versus isolated Zr-BTB-NH2. Through concerted thermodynamic and kinetic optimization, the covalent Zr-BTB-COF achieved high CO and anisaldehyde yields (71.9 and 44.7 mu molg-1h-1) with internal quantum efficiency of 3.75% (365 nm). This bond-resolved interface engineering paradigm establishes a new design framework for synchronizing carbon-neutral cycles with high-value chemical synthesis. (c) 2026, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

The persistent challenge impeding photocatalytic advancement lies in achieving simultaneous efficient utilization of photogenerated carriers for dual value-added reactions. This study demonstrates the synergistic interplay of plasmon-exciton-phonon interactions within non-metallic plasmonic Mo2N quantum dots anchored on ultrathin ZnIn2S4 nanosheets (0D/2D Mo2N/ZnIn2S4), which simultaneously enhances photocatalytic hydrogen evolution and selective oxidation of 4-methoxybenzyl alcohol to 4-methoxybenzaldehyde. Integrated experimental, operando spectroscopic, and theoretical analyses reveal triple cooperative mechanisms: localized surface plasmon resonance at Mo2N sites generates high-energy hot electrons through plasmon-exciton coupling, significantly reducing the apparent activation energy to 4.87 kJ & centerdot;mol(-1); quantum confinement synergizing with the 0D/2D ohmic-junction concentrates excitons at nanoscale interfaces, enabling prolonged carrier lifetime; meanwhile, directional photon-to-phonon energy conversion induces uniform photothermal heating (Delta T = 55.9 degrees C), kinetically accelerating dehydrogenation while balancing redox half-reactions. This synergy achieves sacrificial-free co-production rates of 96.3 mmol & centerdot;h(-1)& centerdot;g(-1) H-2 and 38.7 mmol & centerdot;h(-1)& centerdot;g(-1) 4-methoxybenzaldehyde with 13.7% apparent quantum efficiency at 420 nm, establishing a new paradigm for solar-driven chemical refineries via precision plasmon-phonon engineering. (c) 2026, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Transition-metal dichalcogenides (TMDs) are atomically thin semiconductors with outstanding optoelectronic properties, but their applications in high-performance optoelectronic devices are often limited by low intrinsic mobility. Using a diamond anvil cell (DAC) combined with transient absorption spectroscopy, pressure-dependent exciton transport and relaxation dynamics were systematically investigated in few-layer (5 layers) and bulk WS2. Within the pressure range of 0 to 2 GPa, hydrostatic pressure induces a nonmonotonic evolution of exciton mobility, reaching maximum enhancements of approximately 3 times and 5 times in few-layer and bulk WS2, respectively. Simultaneously, the exciton lifetimes are reduced by approximately 4 times and 7 times. Complementary photoluminescence (PL) and Raman measurements reveal that pressure-enhanced interlayer coupling and lattice compression jointly modulate the electronic structure and exciton relaxation pathways, leading to accelerated relaxation dynamics. The nonmonotonic variation in exciton mobility can be attributed to a competitive mechanism between pressure-regulated band broadening effects (reduced effective mass and enhanced dielectric shielding) and increased defect scattering and lattice scattering. It is worth noting that after pressure release, the mobility remains higher and the lifetime is slightly shorter than the initial values. These results reveal the correlated evolution of exciton mobility and lifetime in WS2, identify an optimal pressure window for exciton transport, and elucidate the mechanism of pressure-regulated exciton dynamics, providing insights into the development of high-mobility, fast-response optoelectronic devices.

Superlubricity refers to the state in which friction and wear almost disappear in the interface. Phase transition structural superlubricity (PTSS) is the superlubricity state achieved in liquid-solid interface by contact stress inducing liquid-solid phase transition of the lubricating medium. However, thus far, the maximum Hertz contact stress of PTSS currently realized is only approximately 600 MPa. In this study, PTSS with Hertz contact stress up to 1.313 GPa was achieved at the liquid-solid interface by constructing in situ heterojunction between the solid phase 1-dodecanol molecular layer and the graphene crystalline boundary tribofilm. By covalently modifying graphene with polydopamine, the adsorption capacity of graphene and SiC substrate was significantly enhanced, leading to the growth of crystalline boundary tribofilm with a thickness of 180 similar to 200 nm. In addition, when the contact stress is greater than 137 MPa, 1-dodecanol will undergo liquid-solid phase transformation phenomenon. Solid phase 1-dodecanol molecules self-assemble to form a herringbone-like configuration by forming hydrogen bonds between the hydroxyl groups. These insights provide a novel method for realizing structural superlubricity and bridge the realms of solid superlubricity and liquid superlubricity.

Hydrogen peroxide (H2O2) is an environmentally friendly reagent, and organic semiconductors (OSCs) are ideal photocatalysts for the synthesis of H2O2 due to their well-defined molecular structure, strong donor-acceptor interactions, and efficient charge separation. This review discusses the regulatory mechanisms of functional group modifications in tuning the photocatalytic performance of OSCs, highlighting the relationship between functional group structure and catalytic performance. For example, electron-regulating groups, such as cyano and halogen, induce molecular dipoles, facilitating the migration of photogenerated electrons. Fluorine groups optimize the band structure and prolong carrier lifetime due to their high electronegativity. π-Conjugated extension groups, like anthraquinone and thiophene, expand conjugation, improve visible light capture, and stabilize intermediates through redox cycles. Hydroxyl groups enhance surface hydrophilicity and promote H2O activation, while imine bond protonation adjusts charge distribution and improves selectivity and cycle stability. Multi-active site functional groups, such as sulfonic acid and amide, accelerate reaction kinetics and inhibit H2O2 decomposition. Functional groups enhance light absorption, charge separation, and surface reactions through electronic structure regulation, intermediate adsorption optimization, and proton-electron transfer. Future work should integrate machine learning to identify optimal functional group combinations and develop green functionalization strategies for efficient H2O2 photocatalyst synthesis.