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Breaking Barriers in Ultrafast Spectroscopy and Imaging Using 100 kHz Amplified Yb-Laser Systems
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Breaking the Energy Barrier of Heavy Metal Ion Diffusion in Micropores with Mesoporous 3D Graphene for Fast and Efficient Cu2+ Removal
Efficient removal of heavy metals from water critically depends not only on adsorption capacity but also on ion diffusion kinetics and the associated energy barriers. In conventional carbon adsorbents, severe diffusion confinement within micropores restricts ion transport, resulting in sluggish adsorption kinetics and large apparent activation energies despite high specific surface areas. Here, we demonstrate that this fundamental limitation is overcome by engineering meso/macroporous architectures in the 3D graphene materials synthesized via our discovered alkali-metal reactions with\\\\r\\\\n2\\\\r\\\\nCO. The unique 3D graphene materials possess defect-rich graphene frameworks with interconnected meso/macroporous networks, exhibiting simultaneously high surface area and greatly enhanced meso/macropore volume that enable efficient access to adsorption sites. As a result, the Cu2+ adsorption on 3D graphene proceeds with very low activation energies (4.98 kJ mol–1), which is almost 4 times smaller than on activated carbon (23.1 kJ mol–1). This finding offers a promising platform for efficient and sustainable water purification.
Breaking the Neptunyl Barrier: Direct Access to Neptunium(IV) in Aqueous Solution via Polyoxometalate-Mediated Reduction and Stabilization
Neptunium exhibits truly unique chemistry as its speciation is dominated by the neptunyl(V) ion (NpO 2 + ). Here, in this study, we describe the spontaneous destabilization and reduction of neptunyl(V) via complexation to the Keggin-type polyoxometalate (POM) ligand PW 11 O 39 7– . The POM-mediated reduction of NpO 2 + does not require any reducing agent and occurs within minutes, at room temperature, and in aqueous solution. The resulting [Np(PW 11 O 39 ) 2 ] 10- complex (Np(PW 11 ) 2 ) remains soluble, water-stable, and air-stable for weeks and persists over an extended acidity range. Single-crystal structure, solid-state Raman and UV–visible absorbance characterization of Np(PW 11 ) 2 revealed a mixed alpha/beta isomery of the Keggin ion, forming an unprecedented 50:50 mixture of Np(α-PW 11 ) 2 and Np(α-PW 11 )(β-PW 11 ). Experiments with other tetravalent ions (i.e., Zr 4+ , Hf 4+ , Ce 4+ , and Th 4+ ) indicate that the occurrence of the beta isomer is specific to Np 4+ and independent of the cation’s size. Solution-state characterization of the Np-PW 11 system via UV-visible-NIR absorbance, 31 P NMR, VT NMR, and relaxometry further elucidated the speciation. Moreover, comparative experiments with uranium revealed that the two types of actinyl ions (UO 2 2+ vs NpO 2 + ) undergo drastically different reactions in the presence of PW 11 . UO 2 2+ is not reduced but instead uses PW 11 as a phosphate reservoir and precipitates as uranyl phosphate.
Symmetry-Breaking Charge Separation in Phenylene-Bridged Perylenediimide Dimers
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Forming Bonds While Breaking Old Ones: Isomer-Dependent Formation of H 3 O + from Aminobenzoic Acid During X-ray-Induced Fragmentation
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Using Machine Learning to Understand the Causes of Quantum Decoherence in Solution-Phase Bond-Breaking Reactions
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Environmentally Driven Symmetry Breaking Quenches Dual Fluorescence in Proflavine
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How Solvation Alters the Thermodynamics of Asymmetric Bond-Breaking: Quantum Simulation of NaK + in Liquid Tetrahydrofuran
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