The shuttling effect of lithium polysulfides (LiPSs) is one of the challenges facing the commercialization, which leads to a significant capacity degradation. This paper proposes a novel method to promote polysulfide transformation by employing arginine to regulate the layer spacing of cobalt-nitrogen doped Ti₃C₂T_x MXene (Co-N@Ti₃C₂T_x-Arg). The results revealed that arginine effectively extended the interlayer spacing and promoted the homogeneous dispersion of Co and N atoms, thus endowing the sulfur host with a high catalytic activity during the charging and discharging processes. The extended interlayer spacing increased the specific surface area and captured sufficient LiPSs for subsequent catalytic conversions, while the Co and N doping on the surface of Ti₃C₂T_x significantly promoted the rapid conversion of the LiPSs to Li₂S. Therefore, the S cathode coated with Co-N@Ti₃C₂T_x-Arg exhibited an excellent cycling stability with a low-capacity fading rate of 0.083% over 200 cycles in addition to a high reversible capacity of 1,365.4 mAh g^-1 at 0.1 C.

Repairing tissue defects caused by diseases and traumas presents significant challenges in the clinic. Recent advancements in biomaterials have offered promising strategies for promoting tissue regeneration. In particular, the exploration of 3D macro and microstructures of biomaterials has proven crucial in this process. The integration of macro, micro, and nanostructures facilitates the performance of biomaterials in terms of their mechanical properties, degradation rate, and distinctive impacts on cellular activities. In this review, we summarize the recent progress in biomaterials with hierarchical structures for tissue regeneration. We explore the various methods and strategies employed in designing biomaterials with hierarchical structures of different dimensions. The improvement of physicochemical properties and bioactivities by hierarchically structured biomaterials, including the regulation of mechanical properties, degradability, and the specific functions of cell behaviors, has been highlighted. Furthermore, the current applications of hierarchically structured biomaterials for tissue regeneration are discussed. Finally, we conclude by summarizing the developments of hierarchically structured biomaterials for tissue regeneration and provide future perspectives.

The recent studies of high-pressure synthesis and stabilization of a variety of polynitrogens have had an immense impact on nitrogen chemistry. However, the metallization and superconductivity of solid nitrogen at high pressure have not yet been verified. Here, based on first-principles calculations, we report a remarkable finding of the metallic N₆ hexazine ring stabilized in the 5p-block element nitrides MN₆ (M = Sb, Te, I) at an experimentally accessible pressure of 100 GPa. Strikingly, the 5p-block elements act as precompressors and electron donors for the N sublattice, leading to the Jahn-Teller distortion of the N₆ hexazine ring and endowing the 5p-block element nitrides superconductivity with a high superconducting critical temperature (T_c) of up to 36.8 K, close to the McMillan limit (40 K). This is the first discovery of a nitrogen-based superconductor with distorted N₆ hexazine rings. The high T_c is attributed to the strong electron-phonon coupling that is induced by the phonon softening and the hybridized electronic states between N and 5s and 5p orbitals of 5p-block elements. Our works have broad implications for enriching novel p-block element nitrides and nitrogen chemistry under extreme conditions.

Ferroelectricity is one of the most major physical phenomena in electronic devices due to its sustainable polarity in the absence of an external electric field and its switchability in response to external stimuli. In alignment with the industry trend towards increasingly integrated devices, research into smaller-sized ferroelectric materials becomes indispensable. In the pursuit of achieving the pinnacle of device miniaturization, recent studies have unveiled materials exhibiting sub-nanometric, unit cell-level domains. Concurrently, advances in transmission electron microscopy-based structural characterization techniques have been made, enabling in-depth analysis of the intricate properties of these miniaturized ferroelectric materials. This review highlights the structural mechanism of ferroelectricity in a reduced scale, as well as the recent advancements in electron microscopy techniques for characterizing miniaturized ferroelectric domains, particularly in the fields of in-situ biasing and atomic scale imaging. We believe that this work will provide structural insights for engineering and characterizing ferroelectrics for the design of downsized high-density memory devices at the quantum limit.

Recent breakthroughs in graphitic carbon nitride (g-C₃N₄)-based materials have catalyzed the development of highly effective antibacterial strategies. This comprehensive review delves into the synthesis, mechanistic insights, and applications of g-C₃N₄ in the realm of antibacterial research. The introduction first highlights the importance of antibacterial materials, emphasizing the urgent need for innovative solutions in the face of bacterial infections and the escalating challenges posed by antibiotic resistance. Continuing, the structural attributes and distinctive characteristics of g-C₃N₄ are examined in detail, elucidating its inherent properties that make it a compelling candidate for antibacterial applications. Subsequently, we meticulously dissect various methods used in the synthesis of g-C₃N₄, encompassing both top-down and bottom-up approaches, offering valuable insights into the production of this promising nanomaterial. Furthermore, it delves deeper into the sterilization mechanisms of g-C₃N₄-based nanomaterials, encompassing a spectrum of strategies, including physical structure sterilization, photocatalytic antibacterial effects, enzymatic antibacterial processes, and the synergetic benefits that emerge from the fusion of these mechanisms. Then, it comprehensively examines the practical applications of g-C₃N₄-based nanomaterials in antibacterial endeavors, encompassing their pivotal roles in water purification, air purification, treatment of bacterial infections, and the development of antibacterial layers in diverse settings. In conclusion, we encapsulate the crux of our findings and provide a forward-looking perspective on the potential challenges and opportunities in the arena of g-C₃N₄-based materials for antibacterial applications. This review aspires to galvanize further exploration and innovation in the design of high-performance g-C₃N₄-based materials, thereby contributing to the progression of antibacterial solutions.

The significance of the superconducting diode effect (SDE) lies in its potential application as a fundamental component in the development of next-generation superconducting circuit technology. The stringent operating conditions at low temperatures have posed challenges for the conventional semiconductor diode, primarily due to its exceptionally high resistivity. In response to this limitation, various approaches have emerged to achieve the SDE, primarily involving the disruption of inversion symmetry in a two-dimensional superconductor through heterostructure fabrication. In this study, we present a direct observation of the supercurrent diode effect in a NbSe₂ nanobridge with a length of approximately 15 nm, created using focused helium ion beam fabrication. Nonreciprocal supercurrents were identified, reaching a peak value of approximately 380 μA for each bias polarity at B_z^max = ± 0.2 mT. Notably, the nonreciprocal supercurrent can be toggled by altering the bias polarity. This discovery of the SDE introduces a novel avenue and mechanism through nanofabrication on a superconducting flake, offering fresh perspectives for the development of superconducting devices and potential circuits.

β-phase √3 × √3R30°-bismuth (Bi) on silicon (Si)(111)7 × 7 surface has been exploited as a template for growing Si films. Two-dimensional Si islands with √3 × √3 reconstruction, parallel to that of Si(111)√3 × √3R30°-Bi, have been resolved by means of scanning tunneling microscopy, grazing-incidence X-ray diffraction (XRD) and low electron energy diffraction. Auger electron spectroscopy and scanning tunneling spectroscopy gave interesting electronic features on two-dimensional Si islands, with the evidence of a reduced band gap to ~0.55 eV, related to the presence of the underneath Bi layer, and atomic structural properties typical of Si(111). These experimental findings fully confirm the recently reported calculation based on the first-principles density functional theory, on the prediction of Si(111) growth on top of β-phase √3 × √3R30°-Bi/Si(111)7 × 7 reconstruction, shedding new light on silicon structures.

Water splitting provides clean hydrogen via different technologies such as alkaline water electrolysis, proton exchange membrane electrolyzers, solid oxide electrolysis cells, and photoelectrolysis, each with advantages and challenges. The focus on alkaline water electrolysis highlights its maturity compared to emerging methods. Non-noble metal catalysts offer increased stability, low cost and operational lifespan. Challenges such as low current density, gas crossover, corrosive electrolytes, and limited efficiency are still to be addressed. These advanced electrocatalysts are summarized for alkaline oxygen and hydrogen evolution reactions. Meanwhile, different factors including product gas bubble management, operation conditions, separator and electrolyte affecting the performance were concluded and discussed. For the promising approach, seawater splitting is still far from large-scale application. Salinity, pH fluctuations, and complex composition are significant obstacles. The review underscores the need for improvements in electrocatalysts to enhance the efficiency, stability, and practicality of water splitting for hydrogen production, ultimately contributing to the growth of the clean hydrogen market and supporting the transition to sustainable energy systems.

Photocatalytic water splitting and CO₂ reduction are conducive to alleviating the increasingly serious environmental problems and ever-tightening energy problems. Among various modification strategies, constructing Z-scheme heterostructures and direct Z-scheme heterostructures, in particular, by mimicking natural photosynthesis, has been widely researched for the effective separation of photogenerated electrons and holes with strong redox ability. However, a low lattice matching degree of different semiconductors often results in serious crystal defects in the composite. Fortunately, van der Waals (vdW) heterostructures constructed through interlayer weak vdW interactions provide a remedy, which not only can ensure the high quality of Z-scheme heterostructures but also preserve the original properties of individual components and induces new properties at the heterogeneous interfaces. Herein, we introduce the fundamentals of direct Z-scheme vdW heterostructure and review the last five-year progress of direct Z-scheme vdW heterostructures for photocatalytic water splitting and CO₂ reduction, highlighting the characteristics and fundamental modification principles of different heterostructures, aiming to provide informative principles for the design of advanced heterostructure photocatalysts for solar energy conversion.

Amorphous materials feature unique structures and physicochemical properties, resulting in their synthesis and applications becoming a dynamic and fascinating new research direction. The high specific surface area, abundant active sites, and good electron transport properties endow amorphous materials with excellent electrocatalytic properties, thus appealing to increasing attention. Based on this, the summary of the current research status of amorphous catalysts in the field of electrocatalysis is urgent and important. In this review, the research progress of amorphous catalysts in electrocatalysis is systematically introduced, focusing on the classification, synthesis methods, modification strategies, characterizations, and electrocatalytic application (including hydrogen evolution reaction, oxygen evolution reaction, oxygen reduction reaction, carbon dioxide reduction reaction, and nitrogen reduction reaction). Finally, this review proposes the prospects and challenges for the future development of high-active and high-selectivity amorphous electrocatalysts.

The chemical designability and diversity of metal-organic frameworks (MOFs) endow them with plenty of anomalous properties, such as negative thermal expansion (NTE). Herein, we investigated the thermal expansion behaviors of the well-known MOF-801, which has been widely used in water adsorption and gas separation. The analyses of variable temperature powder X-ray diffraction and Rietveld refinements revealed a fascinating transition from positive thermal expansion to NTE. Further in situ Raman spectra and pair distribution function investigations shed light on the transition being attributed to the local Zr₆O₈ node distortion rather than a long-range phase transition. Our findings will enhance the comprehension of NTE and contribute to the effective utilization of MOF-801 over a broad temperature range.

The highly adjustable properties of high-entropy alloys (HEAs) offer great potential for developing superior materials for critical structural applications in high-temperature conditions. In this study, Ni-Fe-Cr-Al-V HEA was manufactured by laser powder bed fusion, which has a unique microstructure composed of dislocation substructure and Face-centered cubic + L1₂ coherent structure and achieves the desired strength-ductility combination. Hot isostatic pressing post-treatment was applied on the laser powder bed fusion-processed HEA to further improve the relative density and optimize the mechanical properties. During the hot isostatic pressing process, the precipitation of L1₂ and B2 phases can be ascribed to the precipitation modes dominated by continuous precipitation and discontinuous precipitation, respectively. With the tensile deformation temperature increasing from 773-1,173 K, the softening degree of HEA increases continuously, and the dominant deformation mechanism evolves from intragranular dislocation slip to grain boundary sliding. At temperatures below 773 K, precipitation strengthening significantly improves tensile strength and ductility. At 1,173 K, the grain boundary strength decreases and grain boundary area increases, which promotes grain boundary sliding and contributes to plastic deformation, resulting in significant softening.

Ammonia (NH₃), as an important chemical product, is industrially produced using the traditional energy-intensive Haber-Bosch method at high temperature and pressure. Electrochemical nitrogen reduction reaction (NRR) to synthesize NH₃ at ambient conditions has been considered as a promising candidate for replacing Haber-Bosch process. However, major obstacles, such as poor catalytic activity and selectivity and extensive competitive hydrogen evolution reaction, remain in NRR, which urgently need to be addressed. Single atom electrocatalysts (SACs) have attracted wide attention in view of their nearly 100% atomic utilization and outstanding catalytic performance. In this review, recent theoretical and experimental advances on novel atomically dispersed electrocatalysts for NRR are summarized and highlighted. We start with the fundamental reaction mechanism of NRR. Then, different preparation methods and the strategies of boosting catalytic performance of SACs from the aspects of coordination environment, coordination number, metal-support interaction and spatial microenvironment regulation are presented and analyzed in detail. Following this, the extensive applications of SACs in terms of noble metal based-SACs and transition metal-based SACs in NRR are discussed. Finally, we provide a perspective of the challenges of SACs for NRR, aiming to guide the rational design of advanced NRR catalysts.