National Science Review最新文献

Two-dimensional (2D) van der Waals (vdW) materials are known for their intriguing physical properties, but their rational design and synthesis remain a great challenge for chemists. In this work, we successfully synthesized a new non-centrosymmetric oxide, i.e. InSbMoO₆, with Sb³⁺ lone-pair electrons serving as chemical scissor to generate its 2D vdW crystal structure. Monolayer and few-layer InSbMoO₆ flakes are readily obtained via facile mechanical exfoliation. They exhibit strong second-harmonic generation (SHG) response with an effective second-order nonlinear optical susceptibility [Formula: see text]of 32.4 pm·V^-1. Meanwhile, the SHG response is in-plane anisotropic and directly proportional to the layer thickness, independent of layer parity. In addition, the InSbMoO₆ flakes exhibit excellent thermal and atmospheric stability, along with pronounced anisotropy in Raman spectroscopy. This work implies that using lone-pair electrons as chemical scissor is an effective strategy for designing and synthesizing new 2D vdW materials for integrated photonic applications.

Bio-based aerogels, which are poised as compelling thermal insulators, demand intricate synthesis procedures and have limited durability under harsh conditions. The integration of smart stimuli-response transitions in biomass aerogels holds promise as a solution, yet remains a challenge. Here, we introduce a pioneering strategy that employs reversible-gel-assisted ambient-pressure drying without organic solvents to craft multifunctional bio-based aerogels. By exploiting the thermally reversible gelling propensity of select biomasses, we anchor emulsified bubbles within cross-linked hydrogels, circumventing surface tension issues during mild drying. The resultant aerogels feature a robust porous matrix that is imbued with stable bubbles, yielding low thermal conductivity, high flame retardancy and robust resistance to diverse rigors. This innovative approach facilitates a paradigm shift in intelligent fire protection in which aerogels transition from robust to flexible in response to water stimuli, effectively shielding against thermal hazards and external forces. This work opens up a facile, eco-friendly and mild way to fabricate advanced biomass aerogels with stimuli-responsive transformation.

An in-depth understanding of electrocatalytic mechanisms is essential for advancing electrocatalysts for the oxygen evolution reaction (OER). The emerging oxide pathway mechanism (OPM) streamlines direct O-O radical coupling, circumventing the formation of oxygen vacancy defects featured in the lattice oxygen mechanism (LOM) and bypassing additional reaction intermediates (*OOH) inherent to the adsorbate evolution mechanism (AEM). With only *O and *OH as intermediates, OPM-driven electrocatalysts stand out for their ability to disrupt traditional scaling relationships while ensuring stability. This review compiles the latest significant advances in OPM-based electrocatalysis, detailing design principles, synthetic methods, and sophisticated techniques to identify active sites and pathways. We conclude with prospective challenges and opportunities for OPM-driven electrocatalysts, aiming to advance the field into a new era by overcoming traditional constraints.

Polymer and fiber science has evolved significantly since the 1920s, with polymers becoming integral to both industry and daily life. China's fiber research, initiated in the 1950s, has made substantial societal and technological contributions, particularly in chemical fibers. How will future advancements in polymers and fibers address ongoing challenges and drive further innovation? NSR spoke to Prof. Stephen Cheng, a member of the National Academy of Engineering (U.S.) and former Dean of the College of Polymer Science and Polymer Engineering at the University of Akron. He is currently Dean and Honorable Professor at South China University of Technology. His research interests center on the condensed states in polymers, liquid crystals, surfactants and hybrid materials, focusing on the interactions, responses, dynamics and structures of materials at varying lengths, energy and timescales, in which the material itself embodies the technology.

The poor oxidation resistance of traditional electrolytes has hampered the development of high-voltage potassium-ion battery technology. Here, we present a cosolvent electrolyte design strategy to overcome the high-voltage limitations of potassium-ion electrolyte chemistries. The cosolvent electrolyte breaks the dissolution limitation of the salt through ion-dipole interactions, significantly enlarging the anion-rich solvation clusters, as verified by the insitu synchrotron-based wide-angle X-ray scattering experiments. Furthermore, the large anion-rich solvation clusters also facilitate the formation of an effective electrode-electrolyte interphase, thereby enhancing compatibility with high-voltage electrodes. The cosolvent electrolyte enables K||Prussian blue cells (2-4.5 V) to operate for >700 cycles with a capacity retention of 91.9%. Our cosolvent electrolyte design strategy paves new avenues for the development of high-voltage potassium-ion batteries and beyond.

Epitaxy is the cornerstone of semiconductor technology, enabling the fabrication of single-crystal film. Recent advancements in van der Waals (vdW) epitaxy have opened new avenues for producing wafer-scale single-crystal 2D atomic crystals. However, when it comes to molecular crystals, the overall weak vdW force means that it is a significant challenge for small molecules to form a well-ordered structure during epitaxy. Here we demonstrate that the vdW epitaxy of Sb₂O₃ molecular crystal, where the whole growth process is governed by vdW interactions, can be precisely controlled. The nucleation is deterministically modulated by epilayer-substrate interactions and unidirectional nuclei are realized through designing the lattice and symmetry matching between epilayer and substrate. Moreover, the growth and coalescence of nuclei as well as the layer-by-layer growth mode are kinetically realized via tackling the Schwoebel-Ehrlich barrier. Such precise control of vdW epitaxy enables the growth of single-crystal Sb₂O₃ molecular film with desirable thickness. Using the ultrathin highly oriented Sb₂O₃ film as a gate dielectric, we fabricated MoS₂-based field-effect transistors that exhibit superior device performance. The results substantiate the viability of precisely managing molecule alignment in vdW epitaxy, paving the way for large-scale synthesis of single-crystal 2D molecular crystals.

Paleogeographic reconstructions are of key importance for understanding the history of continental breakups and amalgamations during Earth's history. A special case is the history of the Asian continent, which, compared to other continents, consists of several large cratons and numerous smaller continental blocks. The history of the assembly of South China remains controversial in terms of the timing, Late Neoproterozoic or Early Paleozoic, and the participating continental blocks, e.g. Yangtze, Cathaysia, India and Australia. Detrital rutile U-Pb dating has significant potential with regard to deciphering tectonic settings as rutile frequently crystallizes during orogenic events associated with the processes of collision and subduction. Detrital zircon U-Pb dating is a perfect instrument for identifying the provenance characteristics and age characteristics of sedimentary sources. An integration of these two methods of dating offers better opportunities for reconstructing tectonic settings. This paper presents a first attempt to reconstruct the Neoproterozoic to Early Paleozoic tectonic history and paleogeography of the whole South China based on U-Pb geochronology of rutile and zircon and Hf-in-zircon isotopes from Lower Jurassic Baitianba Formation sedimentary rocks of the western margin of the Yangtze Block, a major part of South China. Our obtained integrated U-Pb rutile and zircon age data show three main age populations of 960-940 Ma, 630-610 Ma and 530-520 Ma. The new U-Pb detrital rutile and zircon ages, compared with former data from Gondwana and Australia, suggest that Yangtze amalgamated with Cathaysia to form South China during the Sibao orogeny at 960-940 Ma. The detrital rutile and zircons of the new 630-610 Ma age group could have been delivered from western Australia during the Late Neoproterozoic to Cambrian Paterson-Petermann orogeny. The abundant 530-520 Ma detrital rutile and zircon ages fit well with the coeval zircon age populations recorded in Gondwana-derived terranes, like India and Indochina.