This review summarizes recent advances in the design and synthesis of stable MOFs and highlights the relationships between the stability and functional applications.

The general synthesis and control of the coordination environment of single-atom catalysts (SACs) remains ag reat challenge.H erein, ag eneral host-guest cooperative protection strategy has been developed to construct SACs by introducing polypyrrole (PPy) into abimetallic metal-organic framework. As an example,the introduction of Mg 2+ in MgNi-MOF-74 extends the distance between adjacent Ni atoms;t he PPy guests serve as Nsource to stabilizethe isolated Ni atoms during pyrolysis.Asaresult, aseries of single-atom Ni catalysts (named Ni SA -N x -C) with different Nc oordination numbers have been fabricated by controlling the pyrolysis temperature. Significantly,t he Ni SA -N 2 -C catalyst, with the lowest N coordination number,a chieves high CO Faradaic efficiency (98 %) and turnover frequency (1622 h À1 ), far superior to those of Ni SA -N 3 -C and Ni SA -N 4 -C,inelectrocatalytic CO 2 reduction. Theoretical calculations reveal that the low Nc oordination number of single-atom Ni sites in Ni SA -N 2 -C is favorable to the formation of COOH* intermediate and thus accounts for its superior activity.Single-atom catalysts (SACs), featured with metal atoms dispersed at atomic level, can achieve amaximal utilization of metal atoms and have demonstrated excellent catalytic performance for various reactions. [1] Combining the merits of both heterogeneous and homogenous catalysts,SACshave been regarded as akind of unique heterogeneous catalysts to serve as an ideal model for the exploration of structureproperty relationships during reaction processes. [2] Theatomically dispersed metal atoms of SACs are stabilized by the support through coordination interaction to minimize their surface energy.T herefore,t he local coordination environ-ment usually plays asignificant role for both catalytic activity and selectivity of SACs.A lthough much work has been devoted in this field, to our knowledge,accurate control over the coordination environment of SACs at an atomic level remains agreat challenge and has been rarely investigated. [3] Metal-organic frameworks (MOFs), ac lass of crystalline porous materials with well-defined structures and diverse compositions,n ot only exhibit great potentials for applications in diverse fields, [4] but also are promising precursors to produce desired materials for energy and catalysis. [5] Particularly,MOFs have recently emerged as an ideal platform for the construction of SACs,a st he targeted metal atoms in MOFs can be rationally and spatially separated in an atomically dispersed form. [6] More specifically,b ecause of the precisely designable and tailorable structures and components in MOFs,i ti sc onvenient to realize coordination environment regulation of SACs based on MOFs. [3b,c] While great progress has been achieved, the currently available strategies towards MOF-based SACs are limited to MOFs involving abundant Na toms,s uch as ZIFs [3b,c, 6c,d, 7] and porphyrinic MOFs. [8] Given that Na toms are not involved in most MOFs,itishighly desired to develop amore general approach for the ...

Organic/inorganic hybrid lead halide perovskites are promising optoelectronic materials due to their unique structure, excellent properties, and fascinating potential applications in lighting, photovoltaic, etc. However, perovskite materials are very sensitive to moisture and polar solvent, which greatly hinders their practical applications. Here, highly luminescent perovskite-polystyrene composite beads with uniform morphology are prepared via a simple swelling-shrinking strategy. This process is carried out only in nonpolar toluene and hexane without the addition of any polar reagents. As a result, the as-prepared composite beads not only retain high luminescence but also exhibit superior water-resistant property. The composites emit strong luminescence after being immersed into water over nine months. Moreover, even in some harsh environments such as acid/alkali aqueous solution, phosphate buffer solution, and Dulbecco's modified eagle medium biological buffers, they still preserve high luminescence. The applications in light-emitting diodes and cellular labeling agents are also carried out to demonstrate their ultrastability.