Secondary metal ion-induced electrochemical reduction of U(VI) to U(IV) solids.

Recent studies have shown that aqueous U(VI) ions can be transformed into U(VI) precipitates through electrocatalytic redox reactions for uranium recovery. However, there have been no reports of U(IV) solids, such as UO, using electrochemical methods under ambient conditions since low-valence states of uranium are typically oxidized to U(VI) by O or HO. Here we developed a secondary metal ion-induced strategy for electrocatalytic production of U(IV) solids from U(VI) solutions using a catalyst consisting of atomically dispersed gallium on hollow nitrogen-doped carbon capsules (Ga-N-C).

Single-Molecule Traps in Covalent Organic Frameworks for Selective Capture of CH from CH-Rich Gas Mixtures.

Removing trace amounts of acetylene (CH) from ethylene (CH)-rich gas mixtures is vital for the supply of high-purity CH to the chemical industry and plastics sector. However, selective removal of CH is challenging due to the similar physical and chemical properties of CH and CH. Here, we report a "single-molecule trap" strategy that utilizes electrostatic interactions between the one-dimensional (1D) channel of a covalent organic framework (denoted as COF-1) and CH molecules to massively enhance the adsorption selectivity toward CH over CH.

Palladium(II) Modulation Enhances the Water Stability and Aqueous TcO/ReO Removal Performance of Metal-Organic Frameworks.

Improving the water stability of metal-organic frameworks (MOFs) is essential for their use in water pollution treatment and environmental remediation, though it remains technically challenging. Herein, we report a novel cationic MOF constructed with [ThO(OH)(COO)] units and [CoN·Cl] units possessing a ftw-type topology (denoted as ). itself exhibited poor water stability but excellent stability following a palladium(II) modulation strategy.

Engineering the pore environment of antiparallel stacked covalent organic frameworks for capture of iodine pollutants.

Radioiodine capture from nuclear fuel waste and contaminated water sources is of enormous environmental importance, but remains technically challenging. Herein, we demonstrate robust covalent organic frameworks (COFs) with antiparallel stacked structures, excellent radiation resistance, and high binding affinities toward I, CHI, and I under various conditions. A neutral framework (ACOF-1) achieves a high affinity through the cooperative functions of pyridine-N and hydrazine groups from antiparallel stacking layers, resulting in a high capacity of ~2.

Pore Space Partition Synthetic Strategy in Imine-linked Multivariate Covalent Organic Frameworks.

Partitioning the pores of covalent organic frameworks (COFs) is an attractive strategy for introducing microporosity and achieving new functionality, but it is technically challenging to achieve. Herein, we report a simple strategy for partitioning the micropores/mesopores of multivariate COFs. Our approach relies on the predesign and synthesis of multicomponent COFs through imine condensation reactions with aldehyde groups anchored in the COF pores, followed by inserting additional symmetric building blocks (with or symmetries) as pore partition agents.

Functional Carbon Capsules Supporting Ruthenium Nanoclusters for Efficient Electrocatalytic TcO /ReO Removal from Acidic and Alkaline Nuclear Wastes.

The selective removal of the β-emitting pertechnetate ion ( TcO ) from nuclear waste streams is technically challenging. Herein, a practical approach is proposed for the selective removal of TcO (or its surrogate ReO ) under extreme conditions of high acidity, alkalinity, ionic strength, and radiation field. Hollow porous N-doped carbon capsules loaded with ruthenium clusters (Ru@HNCC) are first prepared, then modified with a cationic polymeric network (R) containing imidazolium-N units (Ru@HNCC-R) for selective TcO and ReO binding.

Modulating Anion Nanotraps via Halogenation for High-Efficiency TcO/ReO Removal under Wide-Ranging pH Conditions.

Efficient and sustainable methods for TcO removal from acidic nuclear waste streams, contaminated water, and highly alkaline tank wastes are highly sought after. Herein, we demonstrate that ionic covalent organic polymers (iCOPs) possessing imidazolium-N nanotraps allow the selective adsorption of TcO under wide-ranging pH conditions. In particular, we show that the binding affinity of the cationic nanotraps toward TcO can be modulated by tuning the local environment around the nanotraps through a halogenation strategy, thereby enabling universal pH TcO removal.

Tuning Local Charge Distribution in Multicomponent Covalent Organic Frameworks for Dramatically Enhanced Photocatalytic Uranium Extraction.

Optimizing the electronic structure of covalent organic framework (COF) photocatalysts is essential for maximizing photocatalytic activity. Herein, we report an isoreticular family of multivariate COFs containing chromenoquinoline rings in the COF structure and electron-donating or withdrawing groups in the pores. Intramolecular donor-acceptor (D-A) interactions in the COFs allowed tuning of local charge distributions and charge carrier separation under visible light irradiation, resulting in enhanced photocatalytic performance.

Tuning excited state electronic structure and charge transport in covalent organic frameworks for enhanced photocatalytic performance.

Covalent organic frameworks (COFs) represent an emerging class of organic photocatalysts. However, their complicated structures lead to indeterminacy about photocatalytic active sites and reaction mechanisms. Herein, we use reticular chemistry to construct a family of isoreticular crystalline hydrazide-based COF photocatalysts, with the optoelectronic properties and local pore characteristics of the COFs modulated using different linkers.

Modulating Uranium Extraction Performance of Multivariate Covalent Organic Frameworks through Donor-Acceptor Linkers and Amidoxime Nanotraps.

Covalent organic frameworks (COFs) can be designed to allow uranium extraction from seawater by incorporating photocatalytic linkers. However, often sacrificial reagents are required for separating photogenerated charges which limits their practical applications. Herein, we present a COF-based adsorption-photocatalysis strategy for selective removal of uranyl from seawater in the absence of sacrificial reagents.

Pyridinium salt-based covalent organic framework with well-defined nanochannels for efficient and selective capture of aqueous TcO.

Ionic covalent organic framework (COF) materials with high specific surface areas and well-defined pore structures are desired for many applications yet seldom reported. Herein, we report a cationic pyridinium salt-based COF (PS-COF-1) with a Brunauer-Emmett-Teller (BET) surface area of 2703 m g, state-of-the-art for an ionic COF. Aided by its ordered pore structure, chemical stability, and radiation resistance, PS-COF-1 showed exceptional adsorption properties toward aqueous ReO (1262 mg g) and TcO.

A Novel Endo-Polygalacturonase from with Prebiotics Production Potential: Cloning, Characterization and Application.

In this study, a potential producer of prebiotics, a novel endo-polygalacturonase pePGA from BM-6, was successfully expressed in , characterized and applied to produce pectic oligosaccharides. The optimum temperature and pH of pePGA were 60 °C and 6.0.

Highly Efficient Electrocatalytic Uranium Extraction from Seawater over an Amidoxime-Functionalized In-N-C Catalyst.

Seawater contains uranium at a concentration of ≈3.3 ppb, thus representing a rich and sustainable nuclear fuel source. Herein, an adsorption-electrocatalytic platform is developed for uranium extraction from seawater, comprising atomically dispersed indium anchored on hollow nitrogen-doped carbon capsules functionalized with flexible amidoxime moieties (In-N -C-R, where R denotes amidoxime groups).

Functionalized Iron-Nitrogen-Carbon Electrocatalyst Provides a Reversible Electron Transfer Platform for Efficient Uranium Extraction from Seawater.

Uranium extraction from seawater provides an opportunity for sustainable fuel supply to nuclear power plants. Herein, an adsorption-electrocatalysis strategy is demonstrated for efficient uranium extraction from seawater using a functionalized iron-nitrogen-carbon (Fe-N -C-R) catalyst, comprising N-doped carbon capsules supporting FeN single-atom sites and surface chelating amidoxime groups (R). The amidoxime groups bring hydrophilicity to the adsorbent and offer surface-specific binding sites for UO capture.

Recent advances on preparation and environmental applications of MOF-derived carbons in catalysis.

Carbon materials derived from metal organic frameworks (MOFs) have excellent properties of high surface area, high porosity, adjustable pore size, high conductivity and stability, and their applications in catalysis have become a rapidly expanding research field. In this review, we have summarized the synthesis strategies of MOF-derived carbons with different physical and chemical properties, obtained through direct carbonization, co-pyrolysis and post-treatment. The potential applications of derived carbons, especially monometal-, bimetal-, nonmetal-doped and metal-free carbons in organo-catalysis, photocatalysis and electrocatalysis are analyzed in detail from the environmental perspective.

Oxygen vacancy enhancing the FeO-CeO catalysts in Fenton-like reaction for the sulfamerazine degradation under O atmosphere.

To develop an efficient and reusable heterogeneous Fenton-like catalyst is a great challenge for its application in practical water treatment. Effective oxygen vacancy (OVs)-promoted FeO-CeO catalyst was prepared by a sol-gel method, and applied in the heterogeneous Fenton-like reaction of the sulfamerazine (SMR) degradation. The FeO-CeO catalyst showed good activity and stability, and total SMR conversion was achieved in the Fenton-like reaction after 75 min at pH 3.