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Atmospheric ozone (O3) has long been a threat to human health, however, rational design of dual-function materials for straightforward sensing and removal of trace O3 in the environment (air, water, etc.) remains challenging. Herein, we present a highly stable and hydrophobic two-dimensional Mn(II)-based metal–organic framework (denoted as BUT-82), which shows distinctive color change on exposure to O3 in air or in liquid water due to the oxidation of Mn2+. The O3 concentration could be quantified by analyzing the color changes of BUT-82 using UV/Vis spectroscopy or more facilely using smartphone photography, and the limits of detection for O3 of the two methods were 47 and 274 ppb, respectively. In addition, BUT-82 showed apparently higher capacity for the removal of O3 from dry or highly humid air flows than its starting materials, namely MnCl2·4H2O and a dicarboxylic acid ligand containing a long alkyl chain (3,3′-bis(dodecyloxy)-[1,1′-biphenyl]-4,4′-dicarboxylic acid). Isoreticular expansion of the MOF to tune its performance was also proven feasible. This work offers new insights into the development of new materials for O3 pollution control. [ABSTRACT FROM AUTHOR]

We design and synthesize two stable Zr(IV)-based metal–organic frameworks with high proton conductivity, namely BUT-76 and BUT-77, which are constructed with the same sulfonic acid containing ligand and 8/12 connected Zr6 clusters. The proton conductivity of these two materials at 80 °C and 100% relative humidity (RH) can reach 8.55 × 10−3 and 3.08 × 10−2 S cm−1 correspondingly. Moreover, both BUT-76 and BUT-77 can maintain their high conductivity and framework integrity for at least 120 hours under the test conditions. XRD diffraction measurements and comprehensive molecular simulations are conducted to explore how the increased connectivity of Zr6 clusters can significantly enhance the proton conductivity of the materials by changing the proton carrier concentration and hydrogen-bonding network. Furthermore, the BUT-77 mixed-matrix membrane shows a proton conductivity value of 1.25 × 10−3 S cm−1 (80 °C, 100% RH). This work not only presents promising candidate materials for proton exchange membranes, but also demonstrates an example to use MOF as a platform to reveal the relationship between structural features and proton conductivity. [ABSTRACT FROM AUTHOR]