Lithium polysulphides generated during discharge in the cathode of a lithium-sulphur redox cell are important, but their dissolution into the electrolyte from the cathode during each redox cycle leads to a shortened cycle life. Herein, we use in situ spectroelectrochemical measurements to demonstrate that sp2 nitrogen atoms in the organic linkers of nanocrystalline metal-organic framework-867 (nMOF-867) are able to encapsulate lithium polysulphides inside the microcages of nMOF-867, thus helping to prevent their dissolution into the electrolyte during discharge/charge cycles. This encapsulation mechanism of lithiated/delithiated polysulphides was further confirmed by observations of shifted FTIR spectra for the C = N and C-N bonds, the XPS spectra for the Li-N bonds from nMOF-867, and a visualization method, demonstrating that nMOF-867 prevents lithium polysulphides from being dissolved in the electrolyte. Indeed, a cathode fabricated using nMOF-867 exhibited excellent capacity retention over a long cycle life of 500 discharge/charge cycles, with a capacity loss of approximately 0.027% per cycle from a discharge capacity of 788 mAh/g at a high current rate of 835 mA/g.

Perovskite solar cells (PSCs) have great potential as an efficient solar energy harvesting system due to their outstanding optoelectronic properties, but the charge accumulation and recombination, as well as the moisture-induced degradation of the light-absorbing perovskite layers, remain great bottlenecks in practical applications for future technology. As a solution to this challenge, here we report a strategy to realize moisture-stable PSCs allowing fast charge transfer that, in turn, leads to high power conversion efficiency (PCE). Hybridization of hygroscopic copper­(II) benzene-1,3,5-tricarboxylate metal–organic frameworks (Cu-BTC MOFs) with a light-absorbing perovskite layer for PSCs, where a moderate level of moisture attracted by Cu-BTC MOFs during the synthesis step, leads to enhanced perovskite crystallization. Besides, the perovskite–MOF hybrid facilitates the transfer of photoexcited electrons from the perovskite to TiO2 by providing additional channels for electron extraction. This enables a high PCE of 20.5% in a triple-cation perovskite–MOF device with negligible hysteresis compared to reference devices. Moreover, the perovskite–MOF hybrid exhibits high stability in ambient air under dark conditions over a long period (up to 22 months), while the unmodified counterpart quickly decomposes into PbI2. Consequently, this work provides a promising clue to realizeing fast charge transfer and high stability for high-performance PSCs.

Combination of different nanoparticles has been suggested as a promising approach to realize advanced functionalities for many applications. Herein, we report a new method to make uniform sized nanoparticle arrays in a network by arranging a micelle monolayer in an ordered fashion on the conductive nitrogen-doped graphene (NG). Moreover, coarrangement of two different arrays using both metal and metal oxide nanoparticles on the conductive graphene is found to result in the synergistic and cooperative photocatalytic activity for production of hydrogen from water using solar energy, with the excellent performance attributed to efficient electron transfer from one nanoparticle through the conductive NG to the other nanoparticle in a single-layer network. Consequently, this work suggests a promising solution to design high-performance catalysts in a network of different nanoparticle arrays on thin and flexible conductive substrates.

Gas adsorption of periodic mesoporous organosilica (PMO) containing bipyridine ligands within the framework (BPy-PMO) has been studied by in situ gas adsorption powder X-ray diffraction (XRD) analysis. Both Ar and CO2 molecules showed strong affinity with organic moiety than silica during monolayer adsorption, even though CO2 is localized more than Ar due to the strong interaction with bipyridine. During multilayer adsorption, adsorbates tend to be located on the silica layers rather than organic and uniformly distributed on the framework surface at the end of this process. The interpenetration of adsorbates within the organic domain of BPy-PMO pore wall enhances rigidity of the framework until capillary condensation, confirmed by decrease of full width at half-maxima (FWHM) of XRD peaks. A molecular simulation study supported the in situ XRD data, and these results provided a full understanding of how the framework environment influences the adsorption behavior of different adsorbates.

Herein, we report the adsorbate behavior in individual local pores of MIL-101, which is a metal−organic framework (MOF) with two heterogeneous mesopores and different metal sites, by combining adsorbate isotherms and in situ crystallography profiles. The in situ mapping shows that the substrate−adsorbate interaction affects the initial adsorption and pore condensation steps. The monolayer adsorption gradient changes greatly depending on the framework metal−adsorbate attraction force. Also, broad inflection points are found in adsorption isotherms, and the initial shape depends on the different metals. Besides, the capillary condensation at a pore draws adsorbates from other local pores. This leads to the local negative uptake behavior in individual pore isotherms. At higher pressure, they move to a larger space, whereas in a relatively low-pressure range the attraction force between the MOF framework and guest molecule influences the amount of rearranged guest molecules. Furthermore, the origin of the characteristic adsorption behavior based on the metals constituting the MOFs and the relative strength of substrate−adsorbate and adsorbate−adsorbate interactions are elucidated through the combined study of electron densities in pores, electron paramagnetic resonance spectroscopy spectra, and density functional theory and Monte Carlo simulations to uncover the previously veiled information on adsorption behavior.