Nickel cations have been introduced into framework sites of the magnesium dioxiterephthalate MOF, CPO-27(Mg), via a procedure involving post-synthetic treatment with an aqueous solution of Ni 2+ cations and a weak acid. The final solids have Ni concentrations up to 70 mol% of the total cation content. Selected area EDX analysis, synchrotron X-ray powder diffraction and XPS surface analysis indicate that Ni 2+ is distributed throughout the crystals with highest concentration at the external surface. A mechanism involving both crystallisation and predominant isomorphous cation replacement is proposed. The modified solids have much enhanced adsorption capacities following simple thermal evacuation under vacuum than unmodified CPO-27(Mg), particularly for N 2 at 77 K, for which uptakes of 17 mmol g −1 are achieved. This is attributed to surface modification that makes the surface more stable to heating under evacuation.

A novel form of mixed-linker ZIF with the RHO topology is one of four zinc-imidazolate frameworks prepared with purine and 2-nitroimidazole. In this structure the linkers order to give a large pore solid with a high pore volume and an unusual symmetry and linker orientation. It possesses extra-framework zinc imidazolate units decorating the internal surface which can be removed to give high porosity.

Despite considerable progress of silicon/carbon (Si/C) composites anodes, they still suffer from high irreversible capacity losses, which are mainly due to continuous Solid Electrolyte Interphase (SEI) layer formation, which consumes a large amount of lithium. To compensate for the active lithium losses, prelithiation of Si-based anodes has been attempted. In this manuscript, we report the effect of prelithiation on Si/C anodes combined with LiNi 0.5 Mn 0.3 Co 0.2 O 2 cathodes in full cell configurations. To prepare Li x Si/C anodes, Si/C electrodes were lithiated electrochemically at 0.1 and 0.5 V vs. Li/Li + in half cell configuration before assembly of the full cell. Special attention is paid to the effect of the degree of prelithiation on initial electrochemical behavior and Li dendrite formation. In this work, electrochemical investigations were performed by using two-electrode and three-electrode measurements. Furthermore, the morphology of the active materials before and after cycling were characterized by post mortem Scanning Electron Microscopy (SEM).

The zero length column (ZLC) technique is used to investigate the stability of Mg- and Ni-CPO-27 metal–organic framework (MOF) crystals in the presence of water and humid flue gas. The design of the ZLC enables the stability test to be conducted over a considerably shorter time period and with lower gas consumption than other conventional techniques. A key advantage over other experimental methods for testing the stability of adsorbents is the fact that the ZLC allows us to quantify the amount adsorbed of every component present in the gas mixture. The developed protocol is based on a two-stage stability test. The samples were first exposed to a humid carbon dioxide and helium mixture in order to study the effect of water on the carbon dioxide adsorption capacity of the samples. In the second stage the samples were exposed to a flue gas mixture containing water. From the preliminary water stability test, the Ni-sample exhibited the highest tolerance to the presence of water, retaining approximately 85% of its pristine CO2 capacity. The Mg-MOFs deactivated rapidly in the presence of water. The Ni-CPO-27 was then selected for the second stage of the protocol in which the material was exposed to the wet flue gas. The sample showed an initial drop in CO2 capacity after the first exposure to the wet flue gas, followed by a stabilisation of the performance over several cycles.

Zeolitic imidazolate frameworks (ZIFs) are a subclass of metal-organic frameworks (MOFs) with extended threedimensional networks of transition metal nodes (bridged by rigid imidazolate linkers), with potential applications in gas storage and separation, sensing and controlled delivery of drug molecules. Here, we investigate the use of 13 C and 15 N solid-state NMR spectroscopy to characterise the local structure and disorder in a variety of singleand dual-linker ZIFs. In most cases, a combination of a basic knowledge of chemical shifts typically observed in solution-state NMR spectroscopy and the use of dipolar dephasing NMR experiments to reveal information about quaternary carbon species are combined to enable spectral assignment. Accurate measurement of the anisotropic components of the chemical shift provided additional information to characterise the local environment and the possibility of trying to understand the relationships between NMR parameters and both local and long-range structure. First-principles calculations on some of the simpler, ordered ZIFs were possible, and provided support for the spectral assignments, while comparison of these model systems to more disordered ZIFs aided interpretation of the more complex spectra obtained. It is shown that 13 C and 15 N NMR are sufficiently sensitive to detect small changes in the local environment, e.g., functionalisation of the linker, crystallographic inequivalence and changes to the framework topology, while the relative proportion of each linker present can be obtained by comparing relative intensities of resonances corresponding to chemically-similar species in cross polarisation experiments with short contact times. Therefore, multinuclear NMR spectroscopy, and in particular the measurement of both isotropic and anisotropic parameters, offers a useful tool for the structural study of ordered and, in particular, disordered ZIFs.

Ordered mesoporous CuNiCo oxides were prepared via nanocasting with varied Cu/Ni ratio to establish its impact on the electrochemical performance of the catalysts. Physicochemical properties were determined along with the electrocatalytic activities toward oxygen evolution/reduction reactions (OER/ORR). Combining Cu, Ni, and Co allowed creating active and stable bifunctional electrocatalysts. CuNiCo oxide (Cu/Ni≈1 : 4) exhibited the highest current density of 411 mA cm−2 at 1.7 V vs. reversible hydrogen electrode (RHE) and required the lowest overpotential of 312 mV to reach 10 mA cm−2 in 1 m KOH after 200 cyclic voltammograms. OER measurements were also conducted in the purified 1 m KOH, where CuNiCo oxide (Cu/Ni≈1 : 4) also outperformed NiCo oxide and showed excellent chemical and catalytic stability. For ORR, Cu/Ni incorporation provided higher current density, better kinetics, and facilitated the 4e− pathway of the oxygen reduction reaction. The tests in Li−O2 cells highlighted that CuNiCo oxide can effectively promote ORR and OER at a lower overpotential.

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