Metal-organic frameworks with photocatalytic bactericidal activity for integrated air cleaning
Ping Li, Jiazhen Li, Xiao Feng, Jie Li, Yuchen Hao, Jinwei Zhang, Hang Wang, Anxiang Yin, Junwen Zhou, Xiaojie Ma & Bo Wang
Nature Communications 10, Article number: 2177 (2019)
Air filtration has become an essential need for passive pollution control. However, most of the commercial air purifiers rely on dense fibrous filters, which have good particulate matter (PM) removal capability but poor biocidal effect. Here we present the photocatalytic bactericidal properties of a series of metal-organic frameworks (MOFs) and their potentials in air pollution control and personal protection. Specifically, a zinc-imidazolate MOF (ZIF-8) exhibits almost complete inactivation of Escherichia coli (E. coli) (>99.9999% inactivation efficiency) in saline within 2 h of simulated solar irradiation. Mechanistic studies indicate that photoelectrons trapped at Zn+ centers within ZIF-8 via ligand to metal charge transfer (LMCT) are responsible for oxygen-reduction related reactive oxygen species (ROS) production, which is the dominant disinfection mechanism. Air filters fabricated from ZIF-8 show remarkable performance for integrated pollution control, with >99.99% photocatalytic killing efficiency against airborne bacteria in 30 min and 97% PM removal. This work may shed light on designing new porous solids with photocatalytic antibiotic capability for public health protection.
https://www.nature.com/articles/s41467-019-10218-9
Photoluminescent organisms: how to make fungi glow through biointegration with lanthanide metal-organic frameworks
Jeferson Rosário, Leonis L. da Luz, Regina Geris, Jéssica G. S. Ramalho, Antônio F. da Silva, Severino Alves Júnior & Marcos Malta
Scientific Reportsvolume 9, Article number: 7302 (2019)
We show that filamentous fungi can emit green or red light after the accumulation of particulate lanthanide metal-organic frameworks over the cell wall. These new biohybrids present photoluminescence properties that are unaffected by the components of the cell wall. In addition, the fungal cells internalise lanthanide metal-organic framework particles, storing them into organelles, thereby making these materials promising for applications in living imaging studies.
https://www.nature.com/articles/s41598-019-43835-x
Imaging defects and their evolution in a metal–organic framework at sub-unit-cell resolution
Lingmei Liu, Zhijie Chen, Jianjian Wang, Daliang Zhang, Yihan Zhu, Sanliang Ling, Kuo-Wei Huang, Youssef Belmabkhout, Karim Adil, Yuxin Zhang, Ben Slater, Mohamed Eddaoudi & Yu Han
Nature Chemistry (2019)
Defect engineering of metal–organic frameworks (MOFs) offers promising opportunities for tailoring their properties to specific functions and applications. However, determining the structures of defects in MOFs—either point defects or extended ones—has proved challenging owing to the difficulty of directly probing local structures in these typically fragile crystals. Here we report the real-space observation, with sub-unit-cell resolution, of structural defects in the catalytic MOF UiO-66 using a combination of low-dose transmission electron microscopy and electron crystallography. Ordered 『missing linker』 and 『missing cluster』 defects were found to coexist. The missing-linker defects, reconstructed three-dimensionally with high precision, were attributed to terminating formate groups. The crystallization of the MOF was found to undergo an Ostwald ripening process, during which the defects also evolve: on prolonged crystallization, only the missing-linker defects remained. These observations were rationalized through density functional theory calculations. Finally, the missing-cluster defects were shown to be more catalytically active than their missing-linker counterparts for the isomerization of glucose to fructose.
https://www.nature.com/articles/s41557-019-0263-4
Isotherms of individual pores by gas adsorption crystallography
Hae Sung Cho, Jingjing Yang, Xuan Gong, Yue-Biao Zhang, Koichi Momma, Bert M. Weckhuysen, Hexiang Deng, Jeung Ku Kang, Omar M. Yaghi & Osamu Terasaki
Nature Chemistry (2019)
Accurate measurements and assessments of gas adsorption isotherms are important to characterize porous materials and develop their applications. Although these isotherms provide knowledge of the overall gas uptake within a material, they do not directly give critical information concerning the adsorption behaviour of adsorbates in each individual pore, especially in porous materials in which multiple types of pore are present. Here we show how gas adsorption isotherms can be accurately decomposed into multiple sub-isotherms that correspond to each type of pore within a material. Specifically, two metal–organic frameworks, PCN-224 and ZIF-412, which contain two and three different types of pore, respectively, were used to generate isotherms of individual pores by combining gas adsorption measurements with in situ X-ray diffraction. This isotherm decomposition approach gives access to information about the gas uptake capacity, surface area and accessible pore volume of each individual pore, as well as the impact of pore geometry on the uptake and distribution of different adsorbates within the pores.
https://www.nature.com/articles/s41557-019-0257-2
Restricting Lattice Flexibility in Polycrystalline Metal‐Organic Framework Membranes for Carbon Capture
Deepu J. Babu Guangwei He Jian Hao Mohammad Tohidi Vahdat Pascal Alexander Schouwink Mounir Mensi Kumar Varoon Agrawal
First published: 14 May 2019
https://doi.org/10.1002/adma.201900855
Although polycrystalline metal‐organic framework (MOF) membranes offer several advantages over other nanoporous membranes, thus far they have not yielded good CO2separation performance, crucial for energy‐efficient carbon capture. ZIF‐8, one of the most popular MOFs, has a crystallographically determined pore aperture of 0.34 nm, ideal for CO2/N2 and CO2/CH4 separation; however, its flexible lattice restricts the corresponding separation selectivities to below 5. A novel postsynthetic rapid heat treatment (RHT), implemented in a few seconds at 360 °C, which drastically improves the carbon capture performance of the ZIF‐8 membranes, is reported. Lattice stiffening is confirmed by the appearance of a temperature‐activated transport, attributed to a stronger interaction of gas molecules with the pore aperture, with activation energy increasing with the molecular size (CH4 > CO2 > H2). Unprecedented CO2/CH4, CO2/N2, and H2/CH4 selectivities exceeding 30, 30, and 175, respectively, and complete blockage of C3H6, are achieved. Spectroscopic and X‐ray diffraction studies confirm that while the coordination environment and crystallinity are unaffected, lattice distortion and strain are incorporated in the ZIF‐8 lattice, increasing the lattice stiffness. Overall, RHT treatment is a facile and versatile technique that can vastly improve the gas‐separation performance of the MOF membranes.
https://onlinelibrary.wiley.com/doi/full/10.1002/adma.201900855
Induced Fit of C2H2 in a Flexible MOF Through Cooperative Action of Open Metal Sites
Heng Zeng Dr. Mo Xie Dr. Yong‐Liang Huang Dr. Yifang Zhao Xiao‐Jing Xie Jian‐Ping Bai Meng‐Yan Wan Prof. Dr. Rajamani Krishna Prof. Dr. Weigang Lu Prof. Dr. Dan Li
Version of Record online:09 May 2019
https://doi.org/10.1002/anie.201904160
Porous materials that can undergo pore‐structure adjustment to better accommodate specific molecules are ideal for separation and purification. Here, we report a stable microporous metal‐organic framework, JNU‐1, featuring one‐dimensional diamond‐shaped channels with a high density of open metal sites arranged on the surface for the cooperative binding of acetylene. Together with its framework flexibility and appropriate pore geometry, JNU‐1 exhibits an induced‐fit behavior for acetylene. The specific binding sites and continuous framework adaptation upon increased acetylene pressure are validated by molecular modeling and in situ X‐ray diffraction study. This unique induced‐fit behavior endows JNU‐1 with an unprecedented increase in the acetylene binding affinity (adsorption enthalpy: up to 47.6 kJ mol−1 at ca. 2.0 mmol g−1 loading).
https://onlinelibrary.wiley.com/doi/10.1002/anie.201904160
A Catalase‐Like Metal‐Organic Framework Nanohybrid for O2‐Evolving Synergistic Chemoradiotherapy
Dr. Zhimei He Dr. Xiaolin Huang Dr. Chen Wang Xiangli Li Dr. Yijing Liu Dr. Zijian Zhou Dr. Sheng Wang Dr. Fuwu Zhang Dr. Zhantong Wang Dr. Orit Jacobson Prof. Jun‐Jie Zhu Dr. Guocan Yu Dr. Yunlu Dai Prof. Xiaoyuan Chen
First published: 02 May 2019
https://doi.org/10.1002/anie.201902612
Tumor hypoxia, the 「Achilles』 heel」 of current cancer therapies, is indispensable to drug resistance and poor therapeutic outcomes especially for radiotherapy. Here we propose an in situ catalytic oxygenation strategy in tumor using porphyrinic metal‐organic framework (MOF)‐gold nanoparticles (AuNPs) nanohybrid as a therapeutic platform to achieve O2‐evolving chemoradiotherapy. The AuNPs decorated on the surface of MOF effectively stabilize the nanocomposite and serve as radiosensitizers, whereas the MOF scaffold acts as a container to encapsulate chemotherapeutic drug doxorubicin. In vitro and in vivo studies verify that the catalase‐like nanohybrid significantly enhances the radiotherapy effect, alleviating tumor hypoxia and achieving synergistic anticancer efficacy. This hybrid nanomaterial remarkably suppresses the tumor growth with minimized systemic toxicity, opening new horizons for the next generation of theranostic nanomedicines.
https://onlinelibrary.wiley.com/doi/full/10.1002/anie.201902612
A Lieb-like lattice in a covalent-organic framework and its Stoner ferromagnetism
Wei Jiang, Huaqing Huang & Feng Liu
Nature Communicationsvolume 10, Article number: 2207 (2019)
Lieb lattice has been extensively studied to realize ferromagnetism due to its exotic flat band. However, its material realization has remained elusive; so far only artificial Lieb lattices have been made experimentally. Here, based on first-principles and tight-binding calculations, we discover that a recently synthesized two-dimensional sp2 carbon-conjugated covalent-organic framework (sp2c-COF) represents a material realization of a Lieb-like lattice. The observed ferromagnetism upon doping arises from a Dirac (valence) band in a non-ideal Lieb lattice with strong electronic inhomogeneity (EI) rather than the topological flat band in an ideal Lieb lattice. The EI, as characterized with a large on-site energy difference and a strong dimerization interaction between the corner and edge-center ligands, quenches the kinetic energy of the usual dispersive Dirac band, subjecting to an instability against spin polarization. We predict an even higher spin density for monolayer sp2c-COF to accommodate a higher doping concentration with reduced interlayer interaction.
https://www.nature.com/articles/s41467-019-10094-3