Ultrathin transition-metal-based nanomeshes can perfectly combine the advantages of two-dimensional (2D) ultrathin nanosheets and porous nanostructures, which have wide applications in energy storage and conversion. In this work, we present an etch-free one-step approach to directly synthesize the ultrathin Co 3 O 4 nanomeshes (Co-UNMs) by employing a CoCl 2 /K 3 Co(CN) 6 cyanogel as the reaction precursor. The 2D planar structural unit and solid properties of the cyanogel result in the preferential assembly of generated crystal nuclei at the solid−liquid interface (i.e., cyanogel−solution interface) in the 2D direction, which plays a key role in the formation of nanomeshes. The as-prepared Co-UNMs with 1.5 nm thickness and abundant pores have high surface area and numerous defect atoms, resulting in enhanced activity for the oxygen evolution reaction (OER) in alkaline media, such as a low overpotential of 307 mV at 10 mA cm −2 , a small Tafel slope of 76 mV dec −1 , and attractive durability in 1 M KOH electrolyte.

As trategy called ultramicroporous building unit (UBU) is introduced. It allows the creation of hierarchical biporous features that work in tandem to enhance gas uptake capacity and separation. Smaller pores from UBUs promote selectivity,w hile larger inter-UBUp acking pores increase uptake capacity.T he effectiveness of this UBUs trategy is shown with ac obalt MOF (denoted SNNU-45) in which octahedral cages with 4.5 pore sizeserve as UBUs.The C 2 H 2 uptake capacity at 1atm reaches 193.0 cm 3 g À1 (8.6 mmol g À1 ) at 273 Kand 134.0 cm 3 g À1 (6.0 mmol g À1 )at298 K. Suchhigh uptake capacity is accompanied by ahigh C 2 H 2 /CO 2 selectivity of up to 8.5 at 298 K. Dynamic breakthrough studies at room temperature and 1atm show aC 2 H 2 /CO 2 breakthrough time up to 79 min g À1 ,among top-performing MOFs.Grand canonical Monte Carlo simulations agree that ultrahigh C 2 H 2 /CO 2 selectivity is mainly from UBUultramicropores,while packing pores promote C 2 H 2 uptake capacity.

The concept of high-performance excited-state intramolecular proton transfer (ESIPT)-based fluorescent metal− organic framework (MOF) probes for Al 3+ is proposed in this work. By regulating the hydroxyl groups on the organic linker step by step, new fluorescent magnesium−organic framework (Mg−MOF) probes for Al 3+ ions were established based on the ESIPT fluorescence mechanism. It is observed for the first time that the number of intramolecular hydrogen bonds between adjacent hydroxyl and carboxyl groups can effectively adjust the ESIPT process and lead to tunable fluorescence sensing performance. Together with the well-designed porous and anionic framework, the Mg−TPP−DHBDC probe decorating with a pair of intramolecular hydrogen bonds exhibits extra-high quantitative fluorescence response to Al 3+ through an unusual turn-off (0−1.2 μM) and turn-on (4.2−15 μM) luminescence sensing mechanism. Notably, the 28 nM limit of detection value represents the lowest record among all reported MOF-based Al 3+ fluorescent sensors up to now. Benefited from the unique turn−off−on ESIPT fluorescence detection process, the Mg−TPP−DHBDC MOF sensor exhibits single Al 3+ detection compared with other 16 common metal ions including Ga 3+ , In 3+ , Fe 3+ , Cr 3+ , Ca 2+ , and Mg 2+ . Impressively, such an Al 3+ selective sensing process can even be fulfilled by the reusable MOF test paper detected by naked eyes. Overall, the quantitative Al 3+ detection, together with the extraordinary sensitivity, selectivity, fast response, and good reusability, strongly supports our concept of ESIPT-based fluorescent MOF Al 3+ probes and makes Mg−TPP−DHBDC one of the most powerful Al 3+ fluorescent sensors.

The conjugation of metal–organic frameworks (MOFs) into different multicomponent materials to precisely construct aligned heterostructures is fascinating but elusive owing to the disparate interfacial energy and nucleation kinetics. Herein, a promising lattice‐matching growth strategy is demonstrated for conductive MOF/layered double hydroxide (cMOF/LDH) heteronanotube arrays with highly ordered hierarchical porous structures enabling an ultraefficient oxygen evolution reaction (OER). CoNiFe‐LDH nanowires are used as interior template to engineer an interface by inlaying cMOF and matching two crystal lattice systems, thus conducting a graft growth of cMOF/LDH heterostructures along the LDH nanowire. A class of hierarchical porous cMOF/LDH heteronanotube arrays is produced through continuously regulating the transformation degree. The synergistic effects of the cMOF and LDH components significantly promote the chemical and electronic structures of the heteronanotube arrays and their electroactive surface area. Optimized heteronanotube arrays exhibit extraordinary OER activity with ultralow overpotentials of 216 and 227 mV to deliver current densities of 50 and 100 mA cm−2 with a small Tafel slope of 34.1 mV dec−1, ranking it among the best MOF and non‐noble‐metal‐based catalysts for OER. The robust performance under high current density and vigorous gas bubble conditions enable such hierarchical MOF/LDH heteronanotube arrays as promising materials for practical water electrolysis.

The high storage capacity versus high selectivity trade-off barrier presents ad aunting challenge to practical application as an acetylene (C 2 H 2 )a dsorbent. As tructureperformance relationship screening for sixty-two high-performance metal-organic framework adsorbents reveals that am oderate pore sized istribution around 5.0-7.5 is critical to fulfill this task. Aprecise pore space partition approach was involved to partition 1D hexagonal channels of typical MIL-88 architecture into finite segments with pore sizes varying from 4.5 (SNNU-26) to 6.4 (SNNU-27), 7.1 (SNNU-28), and 8.1 (SNNU-29). Coupled with bare tetrazole Nsites (6 or 12 bare Ns ites within one cage) as high-density H-bonding acceptors for C 2 H 2 ,the target MOFs offer agood combination of high C 2 H 2 /CO 2 adsorption selectivity and high C 2 H 2 uptake capacity in addition to good stability.T he optimizedS NNU-27-Fem aterial demonstrates aC 2 H 2 uptake of 182.4 cm 3 g À1 and an extraordinary C 2 H 2 /CO 2 dynamic breakthrough time up to 91 min g À1 under ambient conditions.