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Harnessing solar energy by photocatalytically converting oxygen and water into high-value-added H2O2 is a promising way of alleviating both environmental and energy issues. It is worth noting that suppressing detrimental side reactions, such as the generation of •O2−, is a critical approach to enhancing H2O2 production. Herein, a 2-fold interpenetrating 3D uranium-organic framework (YTU-W-1) was developed and introduced for photocatalytic H2O2 production. The material demonstrates a different photocatalytic mechanism when employing uranyl as an initiator, as compared with the conventional semiconductor photocatalytic pathway involving photo-generated charge carriers. Benefiting from the strong hydrogen abstraction effect of the U≡O• and the direct one-step oxygen reduction pathway, YTU-W-1 exhibits enhanced photocatalytic performance for H2O2 production with yield efficiency of 221 µmol h−1 g−1. Furthermore, YTU-W-1 displays a high H2O2 selectivity of 68%, confirmed by rotating ring-disk electrode (RRDE) measurement. DFT calculations were used to elucidate the critical role of uranyl in the photocatalytic oxygen reduction reaction for H2O2 production. This research introduces an innovative approach to photo driven H2O2 production, underscoring the potential for heterogeneous catalysts to engage in photocatalytic reactions independently of photo-generated charge carriers. [ABSTRACT FROM AUTHOR]

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. Specifically, a new HKUST‐1@Cu2O heterostructure was successfully synthesized by simply irradiating a methanol solution dispersed of HKUST‐1 with gamma ray under ambient conditions. The copper source of Cu2O was directly derived from in situ radiation etching and reduction of the parent HKUST‐1, without the use of any additional copper reagents. Significantly, the resulting HKUST‐1@Cu2O heterostructure exhibits remarkable catalytic performance, with a catalytic rate constant nearly two orders of magnitude higher than that of the parent HKUST‐1. [ABSTRACT FROM AUTHOR]

In conjunction with theoretical calculations, the in vitro and in vivo uranyl binding capabilities of a bidentate picolinate (Pic) ligand and its pentadentate derivative (H2dpa) are investigated. The planar N3O2-donor configuration of H2dpa matches the typical pentagonal-bipyramid coordination geometry of uranyl, demonstrating a remarkable removal preference for uranyl in the kidneys. [ABSTRACT FROM AUTHOR]

The development of adsorbent materials for effective capture of radioactive iodomethane (CH3I) from the off-gas of used nuclear fuel reprocessing, remains a significant and challenging line of research because currently state-of-art adsorbents still suffer from low binding affinity with CH3I. Here, we proposed a brand-new adsorption topological structure by developing a 2D interdigitated layered framework, named SCU-20, featuring slide-like channel with multiple active sites for CH3I capture. The responsive rotating-adaptive aperture of SCU-20 enables the optimal utilization of all active sites within the pore for highly selective recognition and capture of CH3I. A record-breaking CH3I uptake capacity of 1.84 g/g was achieved under static sorption conditions with saturated CH3I vapor. Both experimental and theoretical findings demonstrated that the exceptional uptake of SCU-20 towards CH3I can be attributed to the confined physical electrostatic adsorption of F sites, coupled with the chemical nitrogen methylation reaction with uncoordinated N atoms of pyrazine. Moreover, dynamic CH3I uptake capacity potentially allows for the capture of CH3I in simulated real-world off gas reprocessing conditions. This study highlights the potential of SCU-20 as a promising candidate for efficient capture of iodine species and contributes to the development of effective solutions for radioactive iodine remediation. [ABSTRACT FROM AUTHOR]

Large volumes of water containing tritium are generated during the operation, decommissioning, and incident-management of nuclear installations and related facilities, and are expected to increase with the ongoing expansion of nuclear power generation. If released into the environment, this water could pose a substantial environmental threat to living organisms. However, conventional isotope separation techniques, such as cryogenic distillation and catalytic exchange, are inadequate for efficiently isolating significant quantities of low-level tritiated water because of the complex machinery and excessive energy required, and the potential for hydrogen-gas detonation. In contrast, water distillation (WD), as a traditional technology, has the unique advantages of simple operation, no corrosive and toxic substances, and no hydrogen explosion risk, but problems of small separation coefficient and low efficiency always exist in this technique. However, the separation effect of WD can be effectively improved by improving the process variables in the process of WD, such as temperature, distillation column diameter, and packing dimensions, so as to adapt WD to the separation of industrial tritiated water. This study provides a thorough exposition of the basic principles and distinctive features of water distillation and examines the effect of various operational parameters on separation efficiency to adapt the process for the industrial separation of tritiated water. The impact of various process variables on the separation efficiency of tritiated water via distillation was investigated, and results show that optimizing these variables can markedly improve the separation efficiency of water distillation. In particular, decreasing the dimensions of the packing material or altering its properties can lead to higher separation factors and lower residual tritiated water concentration. These findings suggest that water distillation can be used for the separation of tritiated water. By optimizing its operational parameters, water distillation can become a viable method for the industrial separation of tritiated water and is expected to play a significant role in this field in the future.

Unsupported non-bridged uranium-carbon double bonds have long been sought after in actinide chemistry as fundamental synthetic targets in the study of actinide-ligand multiple bonding. Here we report that, utilizing Ih(7)-C80 fullerenes as nanocontainers, a diuranium carbide cluster, U=C=U, has been encapsulated and stabilized in the form of UCU@Ih(7)-C80. This endohedral fullerene was prepared utilizing the Krätschmer-Huffman arc discharge method, and was then co-crystallized with nickel(II) octaethylporphyrin (NiII-OEP) to produce UCU@Ih(7)-C80·[NiII-OEP] as single crystals. X-ray diffraction analysis reveals a cage-stabilized, carbide-bridged, bent UCU cluster with unexpectedly short uranium-carbon distances (2.03 Å) indicative of covalent U=C double-bond character. The quantum-chemical results suggest that both U atoms in the UCU unit have formal oxidation state of +5. The structural features of UCU@Ih(7)-C80 and the covalent nature of the U(f1)=C double bonds were further affirmed through various spectroscopic and theoretical analyses.

Ultrafine 5 nm ceria isotropic nanoparticles were prepared using the rapid chemical precipitation approach from cerium(III) nitrate and ammonium hydroxide aqueous solutions. The as-prepared nanoparticles were shown to contain predominantly Ce(IV) species. The solubility of nanocrystalline CeO2 at several pH values was determined using ICP-MS and radioactive tracer methods. Phase composition of the ceria samples remained unchanged upon partial dissolution, while the shape of the particles changed dramatically, yielding nanorods under neutral pH conditions. According to X-ray absorption spectroscopy investigation of the supernatant, Ce(III) was the main cerium species in solution at pH < 4. Based on the results obtained, a reductive dissolution model was used for data interpretation. According to this model, the solubility product for ceria nanoparticles was determined to be log Ksp = -59.3 ± 0.3 in 0.01 M NaClO4. Taken together, our results show that the pH dependence of ceria anti- and pro-oxidant activity can be related to the dissolution of CeO2 in aqueous media.