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.

Efficient water splitting demands highly active, low cost, and robust electrocatalysts. In this study, we report the synthesis of penroseite (Ni,Co)Se 2 nanocages anchored on 3D graphene aerogel using Prussian blue analogues as precursor and further their applications in overall water splitting electrolysis. The synergy between the high activity of (Ni,Co)Se 2 and the good conductivity of graphene leads to superior performance of the hybrid toward the water splitting in basic solutions. The (Ni,Co)Se 2 -GA only requires a low cell voltage of 1.60 V to reach the current density of 10 mA cm -2 , making the (Ni,Co)Se 2 -GA hybrid a competitive alternative to noble metal based catalysts for water splitting.

A mesoporous cationic Cr-MOF, termed FJI-C10, containing imidazolium moieties, Lewis acidic Cr sites and free halogens is constructed for the first time by a topology-guided one-pot synthesis. FJI-C10 exhibits excellent performances in CO adsorption (20.2 wt% at 273 K and 1 bar) and chemical fixation of CO into cyclic carbonates without the use of co-catalyst under atmospheric pressure.

The design and synthesis of metal-organic frameworks (MOFs) enclosed with multiple catalytic active sites is favorable for cooperative catalysis, but is is still challenging. Herein, we developed a sequential postsynthetic ionization and metalation strategy to prepare bifunctional multivariate Zr-MOFs incorporating zinc porphyrin and imidazolium functionalities. Using this facile strategy, tetratopic [5,10,15,20-tetrakis(4-carboxyphenyl)porphyrinato]zinc(II) (ZnTCPP) ligands were successfully installed into the cationic Zr-MOF to obtain ZnTCPP⊂(Br)Etim-UiO-66. These MTV-MOFs, including TCPP⊂Im-UiO-66, TCPP⊂(Br)Etim-UiO-66, and ZnTCPP⊂(Br)Etim-UiO-66, were well characterized and used in CO capture and conversion into cyclic carbonate from allyl glycidyl ether and CO under cocatalyst-free and 1 bar CO pressure conditions. It was found that the structural features and CO affinity properties of these MTV-MOFs can be tuned by introducing imidazolium groups or doping zinc sites. Additionally, ZnTCPP⊂(Br)Etim-UiO-66 exhibited enhanced catalytic activities compared to other MTV-MOFs herein for obtaining the 3-allyloxy-1,2-proplyene carbonate product, which was attributed to the cooperative effect of Zn sites and Br ions in this microporous ionic MTV-MOF. ZnTCPP⊂(Br)Etim-UiO-66 can be recycled easily and used at least three times.

The capture of radioactive I 2 vapor from nuclear waste under industrial operating conditions remains a challenging task, as the practical industrial conditions of high temperature (≥150 °C) and low I 2 concentration (∼150 ppmv) are unfavorable for I 2 adsorption. We report a novel guanidinium-based covalent organic framework (COF), termed TGDM, which can efficiently capture I 2 under industrial operating conditions. At 150 °C and 150 ppmv I 2 , TGDM exhibits an I 2 uptake of ∼30 wt %, which is significantly higher than that of the industrial silver-based adsorbents such as Ag@MOR (17 wt %) currently used in the nuclear fuel reprocessing industry. Characterization and theoretical calculations indicate that among the multiple types of adsorption sites in TGDM, only ionic sites can bond to I 2 through strong Coulomb interactions under harsh conditions. The abundant ionic groups of TGDM account for its superior I 2 capture performance compared to various benchmark adsorbents. In addition, TGDM exhibits exceptionally high chemical and thermal stabilities that fully meet the requirements of practical radioactive I 2 capture (high-temperature, humid, and acidic environment) and differentiate it from other ionic COFs. Furthermore, TGDM has excellent recyclability and low cost, which are unavailable for the current industrial silver-based adsorbents. These advantages make TGDM a promising candidate for capturing I 2 vapor during nuclear fuel reprocessing. This strategy of incorporating chemically stable ionic guanidine moieties in COF would stimulate the development of new adsorbents for I 2 capture and related applications.

Hypercrosslinked MPILs with high ionic density and excellent textural properties were prepared for efficient simultaneous CO2 adsorption and cycloaddition.

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