Publications by authors named "Zhifang Chai"

Article Synopsis
  • The removal of radioactive gaseous iodine, especially methyl iodide, is essential for safe nuclear energy management and waste disposal, but effective capture methods are still being researched.* -
  • This study used a "theory-first" approach to create a new material, piperazine-based covalent organic framework (Pip-COF), designed specifically for high capture efficiency of methyl iodide.* -
  • Testing showed Pip-COF performs exceptionally well, capturing up to 39 mg/g at 75 °C and 78 mg/g at 25 °C, far exceeding previous materials, and the study highlights the importance of rational design in addressing environmental challenges.*
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We report the synthesis and optical characterization of a series of metal chalcogenides, ASiSTe (A = Sr, Ba, Eu), highlighting the metal-atom substitution strategy for the discovery of a high-performance metal chalcogenide-based near-infrared (NIR) scintillator of EuSiSTe. EuSiSTe exhibits exceptionally broad NIR emission with a full width at half-maximum of 210 nm, the largest among all known Eu-based NIR emitters. EuSiSTe has a high light yield of 41697 photons/MeV and excellent resistance to hygroscopicity.

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Micronuclear batteries harness energy from the radioactive decay of radioisotopes to generate electricity on a small scale, typically in the nanowatt or microwatt range. Contrary to chemical batteries, the longevity of a micronuclear battery is tied to the half-life of the used radioisotope, enabling operational lifetimes that can span several decades. Furthermore, the radioactive decay remains unaffected by environmental factors such as temperature, pressure and magnetic fields, making the micronuclear battery an enduring and reliable power source in scenarios in which conventional batteries prove impractical or challenging to replace.

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Metal-anchored covalent organic frameworks (COFs), as a class of significant derivatives of COFs, are widely used as heterogeneous catalysts in diverse chemical reactions. However, they are typically synthesized via post-treatment strategies, which often lead to the decline of COF crystallinity, decrease of porous properties, instability in catalytic performances, generation of additional chemical waste, and consumption of excess time and energy. In this work, we demonstrate an approach to construct a metal-functionalized COF via a one-pot method induced by γ-ray radiation.

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Article Synopsis
  • Traditional adsorbents struggle to effectively remove iodate (IO₃⁻) due to limited capacity, relying mainly on ion exchange or hard acid-hard base interactions.
  • A novel redox-active cationic polymer network (SCU-CPN-6) was synthesized by combining guanidino and phenolic groups, achieving a remarkable adsorption capacity of 896 mg/g for IO₃⁻.
  • This innovative approach demonstrates a synergistic effect of ion exchange and redox mechanisms, outperforming existing methods and paving the way for the development of advanced adsorbents for various applications.
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Metal-organic framework (MOF) based heterostructures, which exhibit enhanced or unexpected functionality and properties due to synergistic effects, are typically synthesized using post-synthetic strategies. However, several reported post-synthetic strategies remain unsatisfactory, considering issues such as damage to the crystallinity of MOFs, presence of impure phases, and high time and energy consumption. In this work, we demonstrate for the first time a novel route for constructing MOF based heterostructures using radiation-induced post-synthesis, highlighting the merits of convenience, ambient conditions, large-scale production, and notable time and energy saving.

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Two-dimensional covalent organic frameworks (2D COFs), featuring a large surface area and 1D pore structure, serve as promising scaffolds for anchoring functional guest compounds, which can significantly enhance their performance and thus expand their potential applications. Postsynthetic strategy for COFs functionalization is versatile but challenging because of their tedious procedure with high time and energy consumption, generation of excess reaction waste, and damage to COF crystallinity. We report in this work a general strategy for the synthesis of inorganic nanocompound-functionalized COF composites in a one-pot way.

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Two-dimensional (2D) MXene materials with innovative properties and versatile applications have gained immense popularity among scientists. The green and environmentally friendly Lewis acid salt etching route has opened up immense possibilities for the advancement of 2D MXene materials. In this study, we precisely etched the Al element from the double A-element MAX phases Ti(SnAl)C by employing Lewis molten salt guided by redox potentials.

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Separation of lanthanide (Ln) and minor actinide (MA) elements and mutual separation between minor actinide elements ( Am(III) and Cm(III)) represent a crucial undertaking. However, separating these elements poses a significant challenge owing to their highly similar physicochemical properties. Asymmetric N-heterocyclic ligands such as -ethyl-6-(1-pyrazol-3-yl)--(-tolyl)picolinamide (Et--Tol-A-PzPy) and -ethyl--(-tolyl)-1,10-phenanthroline-2-carboxamide (ETPhenAm) have recently received considerable attention in the separation of MAs over Ln from acid solutions.

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MAX phases are highly promising materials for electromagnetic (EM) wave absorption because of their specific combination of metal and ceramic properties, making them particularly suitable for harsh environments. However, their higher matching thickness and impedance mismatching can limit their ability to attenuate EM waves. To address this issue, researchers have focused on regulating the electronic structure of MAX phases through structural engineering.

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We present the first example of an TcO anion entrapped within the cavity of a silver cluster, revealing an unprecedented photoinduced charge transfer phenomenon. [Ag(C≡CBu)(TcO)]·(BF) (denoted as ) was successfully synthesized and structurally characterized. Single-crystal X-ray diffraction and Raman spectroscopy reveal that the tetrahedral structure of the TcO anion sustains significant symmetry breaking with weakened Tc-O bond strength under confinement within the Ag(C≡CBu) cluster.

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Dilanthanide complexes with one-electron delocalization are important targets for understanding the specific 4f/5d-bonding feature in lanthanide chemistry. Here, we report an isolable azide-bridged dicerium complex [{(Trapen)Ce}(μ-N)] [Trapen = tris (2-aminobenzyl)amine; TMS = SiMe], which is synthesized by the reaction of tripodal ligand-supported (Trapen)CeCl complex with NaN. The structure and bonding nature of are fully characterized by X-ray crystal diffraction analysis, electron paramagnetic resonance (EPR), magnetic measurement, cyclic voltammetry, X-ray absorption spectroscopy, and quantum-theoretical studies.

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There is an urgent need for highly efficient sorbents capable of selectively removing TcO from concentrated alkaline nuclear wastes, which has long been a significant challenge. In this study, we present the design and synthesis of a high-performance adsorbent, CPN-3 (CPN denotes cationic polymeric nanotrap), which achieves excellent TcO capture under strong alkaline conditions by incorporating branched alkyl chains on the N3 position of imidazolium units and optimizing the framework anion density within the pores of a cationic polymeric nanotrap. CPN-3 features exceptional stability in harsh alkaline and radioactive environments as well as exhibits fast kinetics, high adsorption capacity, and outstanding selectivity with full reusability and great potential for the cost-effective removal of TcO/ReO from contaminated water.

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Article Synopsis
  • Synthesizing large metal-organic framework (MOF) single crystals is challenging due to rapid nucleation leading to many small crystals, making it difficult to grow larger ones.
  • The authors propose using an isotopic substitution strategy that successfully inhibits nucleation and significantly increases crystal sizes, achieving growth up to 165 times larger than normal methods.
  • Their method not only results in the biggest MOF single crystal produced by one-pot synthesis, but also enhances its X-ray detection capabilities, demonstrating the potential of isotopes in improving crystallization processes and applications of large MOF crystals.
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Article Synopsis
  • Luminescent covalent organic frameworks (LCOFs) are important for various applications because they have adjustable emitting properties and robust structures, outperforming small molecule emitters.
  • Researchers developed a robust aminal-linked COF (DD-COF) using perdeuterated light-emitting monomers, achieving a remarkable solid-state photoluminescence quantum yield of 81%, significantly better than existing LCOFs.
  • This high luminescent efficiency results from reduced nonradiative decay pathways, especially from bond vibrations, and the deuterated COF demonstrates improved photostability under UV light as well as enhanced iodine detection performance compared to nondeuterated versions.
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Article Synopsis
  • Dietary exposure to methylmercury (MeHg) is harmful to human cognition, particularly through rice consumption, which is a key source of MeHg.
  • Researchers found a unique pathway in rice plants that converts MeHg to inorganic mercury and then releases it as gaseous mercury without needing light or microorganisms.
  • This pathway prevents significant increases in MeHg levels in rice grains, which could otherwise lead to minor IQ drops in newborns and substantial economic losses globally.
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Plain simulations and enhanced sampling unveil a novel siderocalin (Scn) recognition mode for An-Ent (where An = actinides and Ent = enterobactin) complexes and identify a "seesaw" relationship between actinide affinity to Ent and Scn recognition to an An-Ent complex. Electrostatic interactions predominantly govern competitive binding in both processes. Additionally, hydrolysis-induced negative charge, water expulsion-driven entropy, and Ent's conformational adaptability collectively enhance high-affinity recognition.

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Defects in metal-organic frameworks (MOFs) can significantly change their local microstructures, thus notably leading to an alteration-induced performance in sorption or catalysis. However, achieving de novo defect engineering in MOFs under ambient conditions without the scarification of their crystallinity remains a challenge. Herein, we successfully synthesize defective ZIF-7 through Co gamma ray radiation under ambient conditions.

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Efficient adsorption of palladium ions from acid nuclear waste solution is crucial for ensuring the safety of vitrification process for radioactive waste. However, the limited stability and selectivity of most current adsorbents hinder their practical applications under strong acid and intense radiation conditions. Herein, to address these limitations, we designed and synthesized an aryl-ether-linked covalent organic framework (COF-316-DM) grafted dimethylthiocarbamoyl groups on the pore walls.

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Storage phosphors displaying defect emissions are indispensable in technologically advanced radiation dosimeters. The current dosimeter is limited to the passive detection mode, where ionizing radiation-induced deep-trap defects must be activated by external stimulation such as light or heat. Herein, we designed a new type of shallow-trap storage phosphor by controlling the dopant amounts of Ag and Bi in the host lattice of CsNaInCl.

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A highly sensitive detection of ultraviolet (UV) radiation is required in a broad range of scientific research, chemical industries, and health-related applications. Traditional UV photodetectors fabricated by direct wide-band-gap inorganic semiconductors often suffer from several disadvantages such as complicated manufacturing procedures, requiring multiple operations and high-cost instruments to obtain a readout. Searching for new materials or simple strategies to develop UV dosimeters for quantitative, accurate, and on-site detection of UV radiation dose is still highly desirable.

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Its high coordination number and tendency to cluster make Th suitable for constructing metal-organic frameworks (MOFs) with novel topologies. In this work, two novel thorium-based heterometallic MOF isomers (IHEP-17 and IHEP-18) were assembled from a Th cluster, a multifunctional organic ligand [4-(1-pyrazol-4-yl)benzoic acid (HPyba)], and Cu/Ni cations via the one-pot solvothermal synthesis strategy. The framework features a 6,12-connected new topology net and contains two kinds of supramolecular cage structures, ThM and ThM, suitable for guest exchange.

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Article Synopsis
  • The PUREX process successfully separates plutonium (Pu) from spent nuclear fuel by changing its oxidation state from +IV to +III using acetaldoxime as a reductant.
  • The reduction of Pu(IV) involves two stages, with the second reduction being the slower (rate-determining) step, having an energy barrier of about 19.24 kcal/mol.
  • Structure and spin density analyses reveal that the reductions occur through hydrogen atom transfer and hydroxyl ligand transfer, highlighting the chemical changes and bond formations during the reaction.
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Efficient transfer of charge carriers through a fast transport pathway is crucial to excellent photocatalytic reduction performance in solar-driven CO reduction, but it is still challenging to effectively modulate the electronic transport pathway between photoactive motifs by feasible chemical means. In this work, we propose a thermally induced strategy to precisely modulate the fast electron transport pathway formed between the photoactive motifs of a porphyrin metal-organic framework using thorium ion with large ionic radius and high coordination number as the coordination-labile metal node. As a result, the stacking pattern of porphyrin molecules in the framework before and after the crystal transformations has changed dramatically, which leads to significant differences in the separation efficiency of photogenerated carriers in MOFs.

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