Adsorption-based iodine (I 2 )c apture has great potential for the treatment of radioactive nuclear waste.Inthis study,weapply a"multivariate" synthetic strategy to construct ionic covalent organic frameworks (iCOFs) with al arge surface area, high pore volume,a nd abundant binding sites for I 2 capture.T he optimizedm aterial iCOF-AB-50 exhibits astatic I 2 uptake capacity of 10.21 gg À1 at 75 8 8Cand adynamic uptake capacity of 2.79 gg À1 at % 400 ppm I 2 and 25 8 8C, far exceeding the performances of previously reported adsorbents under similar conditions.i COF-AB-50 also exhibits fast adsorption kinetics,g ood moisture tolerance,a nd full reusability.T he promoting effect of ionic groups on I 2 adsorption has been elucidated by experimentally identifying the iodine species adsorbed at different sites and calculating their binding energies.T his work demonstrates the essential role of balancing the textural properties and binding sites of the adsorbent in achieving ahigh I 2 capture performance.

Radioactive molecular iodine (I2) and organic iodides, mainly methyl iodide (CH3I), coexist in the off-gas stream of nuclear power plants at low concentrations, whereas few adsorbents can effectively adsorb low-concentration I2 and CH3I simultaneously. Here we demonstrate that the I2 adsorption can occur on various adsorptive sites and be promoted through intermolecular interactions. The CH3I adsorption capacity is positively correlated with the content of strong binding sites but is unrelated to the textural properties of the adsorbent. These insights allow us to design a covalent organic framework to simultaneously capture I2 and CH3I at low concentrations. The developed material, COF-TAPT, combines high crystallinity, a large surface area, and abundant nucleophilic groups and exhibits a record-high static CH3I adsorption capacity (1.53 g·g−1 at 25 °C). In the dynamic mixed-gas adsorption with 150 ppm of I2 and 50 ppm of CH3I, COF-TAPT presents an excellent total iodine capture capacity (1.51 g·g−1), surpassing various benchmark adsorbents. This work deepens the understanding of I2/CH3I adsorption mechanisms, providing guidance for the development of novel adsorbents for related applications.

2D heterostructured materials combining ultrathin nanosheet morphology, defined pore configuration, and stable hybrid compositions, have attracted increasing attention for fast mass transport and charge transfer, which are highly desirable features for efficient energy storage. Here, the chemical space of 2D-2D heterostructures is extended by covalently assembling covalent organic frameworks (COFs) on MXene nanosheets. Unlike most COFs, which are generally produced as solid powders, ultrathin 2D COF-LZU1 grows in situ on aminated Ti 3 C 2 T x nanosheets with covalent bonding, producing a robust MXene@COF heterostructure with high crystallinity, hierarchical porosity, and conductive frameworks. When used as lithium hosts in Li metal batteries, lithium storage and charge transport are significantly improved. Both spectroelectrochemical and theoretical analyses demonstrate that lithiated COF channels are important as fast Li + transport layers, by which Li ions can be precisely nucleated. This affords dendrite-free and fast-charging anodes, which would be difficult to achieve using individual components.

Nanostructured molybdenum oxides are promising materials for energy storage, catalysis, and electronic-based applications. Herein, we report the synthesis of MoO 3– x nanosheets ( x stands for oxygen vacancy) via an environmentally friendly liquid exfoliation approach. The process involves the reflux of the bulk α-MoO 3 precursor in water at 80 °C for 7 days. Electron microscopy and atomic force microscopy show that the MoO 3– x nanosheets are a few nanometer thick. MoO 3– x nanosheets exhibit near infrared plasmonic property that can be enhanced by visible light irradiation for a short time (10 min). Photocatalytic activity of MoO 3– x nanosheets for organic dye decolorization is examined using two different dyes (rhodamine B and methylene blue). Under visible light irradiation, MoO 3– x nanosheets make a rapid decolorization for the dye molecules in less than 10 min. The simple synthesis procedure of MoO 3– x nanosheets combined with their remarkable photochemical properties reflect the high potential for using the nanosheets in a variety of applications.

Copper (Cu)-based catalysts generally exhibit high C2+ selectivity during the electrochemical CO2 reduction reaction (CO2RR). However, the origin of this selectivity and the influence of catalyst precursors on it are not fully understood. We combine operando X-ray diffraction and operando Raman spectroscopy to monitor the structural and compositional evolution of three Cu precursors during the CO2RR. The results indicate that despite different kinetics, all three precursors are completely reduced to Cu(0) with similar grain sizes (~11 nm), and that oxidized Cu species are not involved in the CO2RR. Furthermore, Cu(OH)2- and Cu2(OH)2CO3-derived Cu exhibit considerable tensile strain (0.43%~0.55%), whereas CuO-derived Cu does not. Theoretical calculations suggest that the tensile strain in Cu lattice is conducive to promoting CO2RR, which is consistent with experimental observations. The high CO2RR performance of some derived Cu catalysts is attributed to the combined effect of the small grain size and lattice strain, both originating from the in situ electroreduction of precursors. These findings establish correlations between Cu precursors, lattice strains, and catalytic behaviors, demonstrating the unique ability of operando characterization in studying electrochemical processes.