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The separation of ethylene (C2 H4 ) from a mixture of ethane (C2 H6 ), ethylene (C2 H4 ), and acetylene (C2 H2 ) at normal temperature and pressure is a significant challenge. The sieving effect of pores is powerless due to the similar molecular size and kinetic diameter of these molecules. We report a new modification method based on a stable ftw topological Zr-MOF platform (MOF-525). Introduction of a cyclopentadiene cobalt functional group led to new ftw-type MOFs materials (UPC-612 and UPC-613), which increase the host-guest interaction and achieve efficient ethylene purification from the mixture of hydrocarbon gases. The high performance of UPC-612 and UPC-613 for C2 H2 /C2 H4 /C2 H6 separation has been verified by gas sorption isotherms, density functional theory (DFT), and experimentally determined breakthrough curves. This work provides a one-step separation of the ternary gas mixture and can further serve as a blueprint for the design and construction of function-oriented porous structures for such applications.

Two series of lanthanide-based metal-organic frameworks, namely {[Ln(BIPA-TC)0.5(DMA)2(NO3)]·DMA·H2O}n (1-Ln, Ln = Eu, Dy, Sm, Nd) and {[Ln2(BIPA-TC)1.5(DMA)3(H2O)2]·2DMA·2H2O}n (2-Ln, Ln = Eu, Dy, Sm, Nd), were successfully constructed via a solvent regulation strategy based on a π-electron rich tetra-carboxylate ligand (H4BIPA-TC). 1-Ln shows a 4-connected lvt topology with the point symbol of {42·84}, but 2-Ln displays a new 4,4,6-connected wxk1 topology with the point symbol of {43·83}4{46·66·83}2{86}. The solid-state luminescence property and the microporous nature of Eu-MOFs (1-Eu and 2-Eu) indicate that they can potentially be used as luminescent sensors. Fluorescence measurements indicate that Fe3+ exhibits the quenching effect for 1-Eu with the quenching efficiency of 93.1%. 2-Eu is the first MOF sensor for Mg2+ with the lowest detection limit of 1.53 × 10-10 mol L-1 and displays good recyclable capability. Simultaneously, in the presence of other metal ions (Ca2+, Mn2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Pd2+, Al3+, Cr3+and Fe3+), 2-Eu can maintain the selective sensing of Mg2+, indicating its potential for Mg2+ turn-on sensing.

N-doped carbon-encapsulated transition metal selenides (TMSs) have garnered increasing attention as promising electrocatalysts for hydrogen evolution reaction (HER). Accurately regulating the electronic structure of these nanohybrids to reveal the underlying mechanism for enhanced HER performances is still challenging and thus requires deep excavation. Herein, a series of pomegranate-like Ni

The storage and separation of C2H2 and CO2 require specific porous materials having surfaces onto which C2H2 or CO2 molecular can be selectively adsorbed. Through the modification of a multifunctional ligand with −F, −Cl, −NH2, −CH3, −OCH3, and inorganic secondary building units (SBUs) with bipy-N ligands (dimethylamine, pyridine, 4-aminopyridine, and isonicotinic acid) based on a microporous Ni-MOF, the pore environment optimization is realized, achieving the enhancement of the adsorption and separation performances of C2H2 and CO2. The C2H2 uptakes vary from 178.4 to 130.1 cm3 g–1 and CO2 from 83.8 to 44.6 cm3 g–1 at 273 K and 1 atm. The 4-aminopyridine and dimethylamine modified UPC-110 has the highest C2H2/CO2 separation selectivity (5.1), further supported and explained via Grand Canonical Monte Carlo (GCMC) simulation and breakthrough experiments. Our work not only provides new porous materials for efficient C2H2 and CO2 storage but also contributes to the strategy on improving gas adsorption and se...

The functionalized modification of targeted porous metal–organic frameworks (MOFs) is important to improve the adsorption capacity of light hydrocarbon gases. Five isomorphic MOFs with different functional groups (F, Cl, NH2, CH3, and OCH3) are successfully synthesized by systematic functional modification of UMCM-151. By studying the adsorption properties of C2 and C3 hydrocarbons (C2H2, C2H4, C2H6, C3H6, and C3H8), it is found that the electron-withdrawing group functional UMCM-151-F and UMCM-151-Cl exhibit strong affinity for C2H2 (98.71 cm3 g–1 for UMCM-151-F and 90.29 cm3 g–1 for UMCM-151-Cl), while the electron-donating group functional UMCM-151-NH2, UMCM-151-CH3, and UMCM-151-OCH3 have strong affinity for C2H4 (97.89 cm3 g–1 for UMCM-151-NH2, 90.22 cm3 g–1 for UMCM-151-CH3 and 94.13 cm3 g–1 for UMCM-151-OCH3). The differences in affinity of electron effects for light hydrocarbon provide an experimental basis for porous MOFs to improve their light hydrocarbon storage capacity.

Four calcium(II) metal–organic frameworks, [Ca(BD)DMF]·DMF·H2O (1), [Ca2(EDDA)(H2O)2(DMA)]·3H2O (2), [Ca(TTD)(Diox)]·2H2O (3), and [Ca2(DBBD)(H2O)2(DMF)]·2DMF·H2O (4) were designed and constructed by using four different carboxylate ligands, i.e., [2,2′-bipyridine]-5,5′-dicarboxylic acid (H2BD), (E)-5,5′-(diazene-1,2-diyl) diisophthalic acid (H4EDDA), 2′,3′,5′,6′-tetramethyl-[1,1′:4′,1″-terphenyl]-4,4″-dicarboxylic acid (H2TTD), and (E)-4′,4‴-(diazene-1,2-diyl)bis(([1,1′-biphenyl]-3,5-dicarboxylic acid)) (H4DBBD), respectively (DMF = N,N-Dimethylformamide; DMA = Dimethylacetamide; Diox = 1,4-Dioxane). The differences in terms of lengths (6.95–17.68 A), steric hindrance and configurations among the four ligands lead to four different structures of the final calcium complexes. In addition, the solid-state fluorescence of all the complexes have been studied at room temperature, showing shifted maximum emission bands or enhanced fluorescent properties compared to that of free organic ligands.

Developing effective and robust electrocatalysts that are applicable for different pH conditions is promising for variable industrial hydrogen evolution reaction (HER), whereas it remains challenging for designing proper materials and protocols. Herein, we have developed a two-step electrodeposition-hydrothermal strategy to construct heterostructured binary Ni-W sulfides nanosheets based on carbon fiber (NiWS/CF). The electrodeposited nickel oxides film on CF in the first step is sulfurized and concurrently incorporated with tungsten disulfide in the following hydrothermal process. Benefiting from synergistic advantages of bimetallic sulfides as well as interwoven nanosheets for efficient mass/charge transport, the NiWS/CF electrode shows excellent HER performances over a broad pH range from acidic (pH = 0), neutral (pH = 7) to alkaline (pH = 14) media. The NiWS/CF electrode also presents stability in long-term electrolysis in wide PH range for at least 12 h, and its interlaced nanosheets structure are well maintained. Our work may provide general and promising strategies to obtain inexpensive and efficient electrocatalysts for pH-universal hydrogen production.

A Co-based two-dimensional (2D) microporous metal-organic frameworks, [Co2(TMTA)(DMF)2(H2O)2]·NO3−·DMF (UPC-32) has been synthesized based on 4,4′,4′′-(2,4,6-trimethylbenzene-1,3,5-triyl)tribenzoic acid (H3TMTA). UPC-32 features a 2D microporous framework exhibits high adsorption of H2 (118.2 cm3/g, 1.05 wt%, at 77 K), and adsorption heat (Qst) of CO2 (34–46 kJ/mol). UPC-32 with narrow distance between layers (3.8 A) exhibits high selectivity of C3H6/CH4 (31.46) and C3H8/CH4 (28.04) at 298 K and 1 bar. It is the first 2D Co-MOF that showed selective separation of C3 hydrocarbon from CH4.

Based on the 5,10,15,20-tetra(cyanophenyl)porphyrin (CNTCPP) ligand, two supermolecule complexes formulated as [Cu(CNTCPP)]·2DMF (Cu-CNTCPP) and [Zn(CNTCPP)] (Zn-CNTCPP) have been synthesized and structurally characterized by single-crystal X-ray diffraction. Cu-CNTCPP features a 0 dimensional (0D) supramoleculer structure, whereas Zn-CNTCPP is a 2D structure. With coordination unsaturated points, Cu-CNTCPP exhibits electrocatalytic activity toward oxygen evolution reaction (OER) with low potential in 1.0 M KOH, generating a current density of 10 mA cm−2 at an potential of 1.66 V vs. RHE, which means it an efficient electrocatalytic material for OER.

Exploring active and stable electrocatalysts for the acidic oxygen evolution reaction (OER) is necessary to broaden the practical applications of proton exchange membrane electrolyzers. Unfortunately, the active sites of electrocatalysts for the acidic OER, which are the most powerful tool for designing and optimizing OER electrocatalysts, still remain ambiguous. Herein, we synthesize Ag doped Co3O4 with different atomic ratios of Co2+/Co3+ and investigate the effect of preferential exposure of Co2+ in Co3O4 on the acidic OER through systematic experiments for the first time. X-ray photoelectron spectroscopy is used to probe the atomic ratio of Co2+/Co3+ on the surface of Co3O4. The results demonstrate that Co3O4 richer in Co2+ shows the best acidic OER performance, and affords a current density of 10 mA cm−2 at an overpotential of 470 mV along with having a satisfactory stability in H2SO4 solution. Moreover, low-temperature calcination treatment is found to be an effective method to aid preferential growth of Co2+ on the surface of Co3O4, further making our synthesis process more practical and universal. Therefore, this work provides some insight into designing non-precious electrocatalysts for the acidic OER, by identifying active sites and offering a versatile modulation strategy on the preferential growth of real active sites.

By tuning interpenetrated and non-interpenetrated frameworks, a pair of Cu-paddlewheel framework-interpenetration isomers (UPC-34, [Cu3(L)2(H2O)3]·2DMF·3EtOH·3H2O and UPC-35, [Cu3(L)2(H2O)3]·2DMF·2Diox·3H2O) based on a tripodal ligand (H3L = 4,4′-((5-carboxy-1,3-phenylene)bis(ethyne-2,1-diyl))dibenzoic acid) has been synthesized and characterized. The interpenetrated framework (UPC-35) is more stable than the non-interpenetrated one (UPC-34). Due to the 2-fold interpenetration, UPC-35 has a pore size distribution of ∼4.5 A, which is close to the kinetic diameters of light hydrocarbons (C1–C3), and thus exhibits high gas-uptake capacities for C3H6 and C3H8. Furthermore, UPC-35 is an effective adsorbent for the selective separation of C3/C2/C1 light hydrocarbons.

A major goal of metal–organic framework (MOF) research is to adjust the structure and function for specific applications. It is highly desirable to develop new multifunctional MOF materials for selective guest molecule storage/separation and catalysis. Recent advances in the synthesis of MOFs have created new opportunities in this direction. Although many multifunctional MOFs have been synthesized to explore different applications, it is still a challenge to construct MOFs with high physicochemical stability for specific applications. In addition, most of the MOFs only have a microporous structure, which is not conducive to the transportation of substances and the entry of macromolecules, thus limiting the applications of these materials in macromolecular adsorption. Herein, we present three amino-functionalized InIII/AlIII/ZrIV-based MOFs with high physicochemical stability for multifunctional performances. The pore size of these MOFs varies from a few angstroms to the nanometre scale, and their specific surface areas and pore volumes gradually increase with the change of nodes. Further studies reveal that these MOFs are promising candidates as storage mediums for hydrogen (H2) and as separation agents for the selective removal of (C3Hn–C2Hn) from natural gas (NG). The mesoporous Zr-MOF can effectively enrich dye molecules to purify water, and the adsorption dynamics of a series of organic dyes shows that there are no size and charge-selective effects for the adsorption process. Furthermore, the catalytic efficiency and mechanism of Knoevenagel condensation reactions have also been studied in detail. Overall, the three versatile amino-functionalized MOFs highlight the advantages of metal–organic frameworks for designing host materials tailored for applications in hydrogen (H2) storage, light hydrocarbon adsorption/separation, water purification, and catalysis.

A coral-like NiSe@NC nanohybrid as an effective electrocatalyst for the hydrogen evolution reaction (HER) at all pH values, constructed via the in situ selenation of a Ni-MOFs precursor, is reported. The electrocatalyst shows overpotentials of 123 mV, 250 mV and 300 mV in 0.5 M H2SO4, 1.0 M KOH and 1.0 M PBS, respectively, to afford a current density of 10 mA cm-2. Meanwhile, NiSe@NC also exhibits a small Tafel slope and superior long-term stability over a wide pH range. The excellent electrocatalytic performance should be ascribed to the unique coral-like structure with a large BET specific surface area (125.4 m2 g-1) and mesoporous features, as well as synergistic effects between NiSe nanocrystals and highly conductive N-doped porous carbon.

It is intriguing but still challenging to develop non-noble electrocatalysts with efficient catalytic centers to replace Pt-based ones for oxygen reduction reaction (ORR) in both alkaline and acidic conditions. Herein, newly C-S-Zn coordination-structured catalytic centers, originating from the strong interactions between autogenous ZnS and S-C defects, are constructed on Enteromorpha-based porous carbon by a simple pyrolysis and in-situ binding method. The experimental and computational results demonstrate that the C-S-Zn structures produce affluent defect sites and transfer more active electrons from Zn atom to graphite layer to capture and reduce O2, thus enhancing the ORR activities in both alkaline and acidic conditions. The in-situ assembly of C-S-Zn structures, micro/mesoporous architecture, and N/S-self-doped biocarbon represents an upgrading approach for the facile preparation of highly active ORR electrocatalysts from natural biomass.

A barium(II) metal-organic framework (MOF) based on a predesigned amino-functionalized ligand, namely [Ba2(L)(DMF)(H2O)(NO3)1/3]∙DMF∙EtOH∙2H2O (UPC-33) [H3L = 4,4'-((2-amino-5-carboxy-1,3-phenylene)bis(ethyne-2,1-diyl))dibenzoic acid] has been synthesized. UPC-33 is a 3-dimensional 3,18-connected network with fcu topology with a rarely twelve nuclear Ba12(COO)18(NO3)2 cluster. Interestingly, UPC-33 shows permanent pores and high adsorption heat of CO2 (49.92 kJ*mol-1), which can be used as a platform for selective adsorption of CO2/CH4 (8.09). In addition, UPC-33 exhibits high separation selectivity for C3 light hydrocarbons with respect to CH4 (228.34, 151.40 for C3H6/CH4, C3H8/CH4 at 273k and 1 bar), as shown by single component gas sorption and selectivity calculations. Due to the existence of -NH2 groups in the channels, UPC-33 can effectively catalyze Knoevenagel condensation reactions with high yield and substrate size and electron dependency.

Metal–organic frameworks (MOFs) derived transition metal oxides exhibit enhanced performance in energy conversion and storage. In this work, porous hollow Co3O4 with N-doped carbon coating (Co3O4/N–C) polyhedrons have been prepared using cobalt-based MOFs as a sacrificial template. Assembled from tiny nanoparticles and N-doped carbon coating, Co3O4/N–C composite shortens the diffusion length of Li+/Na+ ions and possesses an enhanced conductivity. And the porous and hollow structure is also beneficial for tolerating volume changes in the galvanostatic discharge/charge cycles as lithium/sodium battery anode materials. As a result, it can exhibit impressive cycling and rating performance. At 1000 mA g–1, the specific capacities maintaine stable values of ∼620 mAh g–1 within 2000 cycles as anodes in lithium ion battery, while the specific capacity keeps at 229 mAh g–1 within 150 cycles as sodium ion battery anode. Our work shows comparable cycling performance in lithium ion battery but even better high-rate c...

The fluorescent Pb(II)–metal–organic nanotube, CD-MONT-2, which possesses a large {Pb14} metallamacrocycle, is synthesized by a modified biphasic liquid–solid–liquid (BLSL) strategy. This strategy takes advantage of solid cyclohexanol to avoid generation of by-products, and is suitable for producing CD-MONT-2 on a large scale. Importantly, water-stable CD-MONT-2 can be easily made into H2S test papers by coating a solution mixture of sodium carboxymethyl cellulose and CD-MONT-2′ on glass plates, which have the characteristics of high efficiency, rapidity, and visualization based on its fluorescence “turn-off” response. The CD-MONT-2 based visual test papers can be used without pretreatment and possess excellent sensitivity and stability.

The discovery of metal–organic frameworks (MOFs) mimicking inorganic minerals with intricate topologies requires elaborate linker design guidelines. Herein, the concept of linker desymmetrization into the design of tetratopic linker based Zr‐MOFs is applied. A series of bent tetratopic linkers with various substituents are utilized to construct Zr‐MOFs with distinct cluster connectivities and topologies. For example, the assembly between a bent linker L‐SO2 with C 2v symmetry and an 8‐connected Zr6 cluster leads to the formation of an scu topology, while another flu topology can be obtained by the combination of a novel 8‐connected Zr6 cluster and a bent linker L‐O with C 1 symmetry. Further utilization of restricted bent linker [(L‐(CH3)6)] gives rise to a fascinating (4, 6)‐c cor net, originated from the corundum lattice, with an unprecedented 6‐c Zr6 cluster. In addition, the removal of toxic selenite ions in aqueous solution is performed by PCN‐903‐(CH3)6 which exhibits rapid and efficient detoxification. This work uncovers new structural opportunities for Zr‐MOFs via linker desymmetrization and provides novel design strategies for the discovery of sophisticated topologies for practical applications., A series of bent tetratopic linkers with various substituents are utilized to construct zirconium metal–organic frameworks (Zr‐MOFs) with distinct cluster connectivities and topologies including scu, flu, and cor topology. The discovery here uncovers new structural opportunities for Zr‐MOFs via linker desymmetrization and provides novel design strategies for the discovery of sophisticated topologies for practical applications.

The development of effective bifunctional catalysts for both oxygen reduction reactions (ORRs) and oxygen evolution reactions (OERs) is crucial for improving the performance of charge and discharge processes in rechargeable metal–air batteries. Here, we report a sulfonated cobalt phthalocyanine/carbon nanotube hybrid (CoPc-SO3H/CNT) prepared by a facile anchoring method along with sonication and magnetic stirring. The resulting CoPc-SO3H/CNT hybrid exhibits better catalytic activity for ORRs and OERs than the cobalt phthalocyanine/carbon nanotube hybrid (CoPc/CNT), sulfonated cobalt phthalocyanine (CoPc-SO3H), cobalt phthalocyanine (CoPc) and the carbon nanotube (CNT). The onset potential of CoPc-SO3H/CNT for the ORR in 0.1 M KOH is 0.88 V (vs. RHE), which is higher than that of CoPc/CNT (0.85 V), the CNT (0.80 V), CoPc-SO3H (0.77 V) and CoPc (0.66 V). Meanwhile, the CoPc-SO3H/CNT hybrid shows a much lower OER potential (1.62 V) at a current density of 10 mA cm−2 compared to CoPc-SO3H (1.64 V), CoPc/CNT (1.74 V), the CNT (1.96 V) and CoPc (>2.00 V) in 1 M KOH. Similar patterns are also found in 0.1 M KOH solution. Both the conductive CNT and the electron-withdrawing sulfonic groups are confirmed to benefit the electrochemical oxygen reactions (ORRs/OERs).

The simple and cost-efficient preparation of high-performance nitrogen-doped carbon aerogel (N-CA) for supercapacitors and other applications is still a big challenge. In this work, we have presented a facile strategy to synthesize hierarchically porous N-CA, which is based on solvothermal polymerization of phenol and formaldehyde under hypersaline condition with ethylenediamine (EDA) functioning as both a catalyst and a nitrogen precursor. Benefited from the catalytic effect of EDA on the polymerization, the obtained N-CA has a predominant amount of micropores (micropore ratio: 52%) with large specific surface area (1201.1 m2&middot, g&minus, 1). In addition, nitrogen doping brings N-CA enhanced wettability and reduced electrochemical impedance. Therefore, the N-CA electrode shows high specific capacitance (426 F&middot, 1 at 1 A&middot, 1 in 0.5 M H2SO4) and excellent cycling stability (104% capacitance retention after 10,000 cycles) in three-electrode systems. Besides, a high energy density of 32.42 Wh&middot, kg&minus, 1 at 800 W&middot, 1 can be achieved by symmetric supercapacitor based on the N-CA electrodes, showing its promising application for energy storage. Furthermore, N-CA also exhibits good capacity and long recyclability in the absorption of organic solvents.

Highly selective detection of trace metal ions has become one of the most urgent issues in public security and living systems. Developing a highly efficient fluorescent sensor for manganese(II) (Mn2+) ions is a huge challenge. Herein, by utilizing the solvent regulation approach, a pair of terbium metal–organic frameworks (UPC-36, [Tb2(btdc)3(DMF)(H2O)4]·DMF and UPC-37, [Tb2(btdc)3(H2O)6]) based on a π-electron-rich ligand (H2btdc = 2,2′-bithiophene-5,5′-dicarboxylic acid) has been chosen as highly efficient sensors for the selective detection of Mn2+ ions. Interestingly, the fluorescence of UPC-36 can be quenched by Mn2+, Cu2+, Al3+, Cr3+ and Fe3+ ions, while UPC-37 can only be quenched by Mn2+ ions. For detecting Mn2+ ions, the limit of detection (LOD) values are calculated to be 0.813 mM and 0.715 mM for UPC-36 and UPC-37 respectively. According to the ICP results, UPC-37 has stronger interactions with Mn2+ ions because of the more regular arrangement of ligands existing in UPC-37, so it exhibits a high sensitivity and selectivity (Ksv = 5.25 × 105 M−1).

Due to the advantages of ultrahigh power density, long lifespan and easy integration with wearable and microscale electronics, micro-supercapacitors (MSCs) have attracted great interest in recent years. However, new high-performance electrode materials for such micro-electrochemical energy storage devices require deep excavation. Herein, we precisely synthesized a new 3D bulk MOF and new 2D ultrathin MOF nanosheets with a thickness of less than 10 nm, and utilized them as high-capacitance microelectrode materials for sophisticated all-solid-state MSC devices respectively. Notably, the MSCs based on MOF nanosheets displayed a high areal capacitance of 28.3 mF·cm−2, and a volumetric capacitance of 15.7 F·cm−3 at 0.2 mA·cm−2. Especially, our MSCs exhibited remarkable energy density of 8.7 mWh·cm−3 at a power density of 110.3 mW·cm−3, and excellent cycling lifespans with retention of 96.0% after 10,000 cycles, and all performances are better than the MSCs based on MOF bulks. This work provides a new way to further explore the inherent advantages of MOFs and stimulates the synthesis of advanced MOFs materials for application in microscale energy storage.

The rational design of a highly reactive electronic structure as the active sites is crucial for the development of oxygen reduction reaction (ORR) catalysts. Herein, a unique ethynyl-linked sulfur-containing porphyrin organic polymer (S-POP) is firstly developed as a metal-free catalyst for ORR under acidic conditions, which possess intrinsic porous structures and easily accessible active sites for the adsorption of oxygen. The S-POP exhibits a superior ORR performance with onset potential of 0.82 V and half-wave potential of 0.72 V, achieving one of the best results among metal-free polymer-based ORR catalysts in acidic conditions, the high ORR activity of S-POP is attributed to the exposure of active sites under the test environment. In particular, it is discovered that after replacing pyrrole N by S atoms, the remaining aza N in S-POP exhibit higher ORR activity than those in conventional porphyrin organic polymer (POP). Density functional theory calculations shows that the significant improvement of S-POP over POP is from the redistribution and reduction of the density of charges on aza N, which promotes *O desorb process and decreases the overpotential. This work provides a novel guidance towards designing and modifying metal-free ORR electrocatalysts with a clear electronic structure as the active sites.

The assembly of a fluorescent dicarboxylate ligand with a barium ion resulted in the formation of a 3D metal-organic framework, Ba5(ADDA)5(EtOH)2(H2O)3·5DMF (UPC-17), based on a 1D rod-shaped secondary building unit. The unprecedented solvent-dependent sensitivities of UPC-17 for the detection of Fe(3+)/Al(3+) ions and 4-nitrophenol with high efficiency were observed for the first time. Significantly, UPC-17 exhibits superior "turn-off" detection for the Fe(3+) ion in methanol and acetone emulsions but shows "turn-on" detection in tetrahydrofuran emulsion. Furthermore, the visible color changes in the detection process make them easy to distinguish by the naked eye, which further increases its application potential.

A 3D non-interpenetrating porous metal-organic framework [Pb2(H2TCPP)]·4DMF·H2O (Pb-TCPP) (H6TCPP = 5,10,15,20-tetra(carboxyphenyl)porphyrin) was synthesized by employment of a robust porphyrin ligand. Pb-TCPP exhibits a one-dimensional channel possessing fairly good capability of gas sorption for N2, H2, Ar, and CO2 gases, and also features selectivity for CO2 over CH4 at 298 K. Furthermore, Pb-TCPP shows electrocatalytic activity for water oxidation in alkaline solution. It is the first 3D porous Pb-MOF that exhibits both gas adsorption properties and electrocatalytic activity for an oxygen evolution reaction (OER).

Three rigid, linear ligands, namely 2′,5′-dimethyl-[1,1′:4′,1′′-terphenyl]-4,4′′-dicarboxylic acid (H2L1), triphenyl-6,6′-dicarboxylic acid (H2L2), and 2,2′-bipyridine-5,5′-dicarboxylic acid (H2L3), were used for constructing metal–organic frameworks (MOFs) with Pb(II). With a similar nature of solvent conditions (DMF/EtOH, with different volumes' rates), four structurally diverse MOFs, namely, [Pb(L1)(DMF)] 1, [Pb(L1)(DMF)] 2, [Pb(L2)] 3, and [Pb3(L3)2(Cl−)2] 4, were synthesized and characterized by single-crystal X-ray diffraction, thermogravimetric analysis, elemental analysis, and powder X-ray diffraction measurements. As the numbers of the central benzene ring contained in the ligands changed from three to two, the length of the ligands varied from 15.64 A to 10.89 A, and steric functional groups endowed the three ligands with more variations, such as a 1D zigzag chain of 1, a 2D wave-like layer of 2, a 3D Pb–O–C-based layer of 3, and a 3D Pb–O–Cl-based chain of 4. Solid-state photoluminescence studies were carried out for all the complexes at room temperature.

MoS2 with different (002) intensity have been synthesized for hydrogen evolution reaction (HER) through a facile hydrothermal method at different pH value. MoS2 obtained at pH = 2–3 exhibits the smallest intensity ratio between (002) and (100) peaks (I (002)/(100)) and the largest BET surface area, which implying the restrained growth of (002) plane and the decreasing of stacking layers of MoS2 at low pH. Because (002) plane is inert plane for HER, low pH (pH = 2–3) is more suitable for increasing the active sites of MoS2 than high pH. The results of the electrocatalytic HER confirm that MoS2 synthesized at pH = 2–3 has the smaller Tafel slope and the lower resistance than pH = 7–8 or pH = 12–13. The corresponding capacitive properties show similar results that MoS2 obtained at pH = 2–3 has the highest specific capacitance among the different pH, which identified the best dispersion and largest BET surface area of MoS2 at low pH. Therefore, pH has made important impact on the controlling growth of (002) plane and the improved active sites of MoS2.

Herein, a bimetallic MOF (Co/Fe-MOF) prepared by doping of Fe centers into a Co-MOF structure was explored as a bifunctional electrocatalyst for hydrogen evolution and oxygen evolution. The Fe-doping can greatly enhance the catalytic activity of Co/Fe-MOF, which presents much smaller overpotentials and Tafel slopes than the monometallic Co-MOF in 1.0 ​M KOH solution, and remarkable durability that superior to the corresponding commercial catalysts of Pt/C and RuO2 for both of the two processes. Impressively, the OER activity of Co/Fe-MOF is comparable to the RuO2 and even higher at current densities (≥10 ​mA ​m−2). An electrolyzer by employing the Co/Fe-MOF modified Ni foam as cathode and anode was assembled, which shows better performance and durability for overall water splitting than the system built from Pt/C and RuO2. This work offers thought for future in-depth digging of the potential of MOFs as electrocatalysts and expanding the family of MOFs electrocatalysts.

N-doped carbon-encapsulated transition metal selenides (TMSs) have garnered increasing attention as promising electrocatalysts for hydrogen evolution reaction (HER). Accurately regulating the electronic structure of these nanohybrids to reveal the underlying mechanism for enhanced HER performances is still challenging and thus requires deep excavation. Herein, a series of pomegranate-like Nix Sey @NC core-shell nanohybrids (including Ni0.85 Se @ NC, NiSe2 @NC, and NiSe@NC) through controllable selenization of a Ni-MOF precursor is reported. The component of the nanohybrids can be fine-tuned by tailoring the selenization temperature and feed ratio, through which the electronic structure can be synchronously regulated. Among these nanohybrids, the Ni0.85 Se @ NC exhibits the optimum pH-universal HER performance with overpotentials of 131, 135, and 183 mV in 0.5 m H2 SO4 , 1.0 m KOH, and 1.0 m PBS, respectively, at 10 mA cm-2 , which are attributed to the increased partial density of state at the Fermi level and effective van der Waals interactions between Ni0.85 Se and NC matrix explained by density functional theory calculations.

Tuning the electronic structures of catalysts with heteroatom-doped carbon materials promises advanced electrocatalytic performance, but challenge remains in the control of interface structures. Taking advantage of the highly tunable metal−organic framework (MOF) templates, NiSe2@N-doped carbon (NiSe2@NC) core-shell nano-octahedrons with well controlled interface structures were successfully synthesized and optimized for the hydrogen evolution reaction (HER). Selective selenization of mixed-linker Ni-MOFs allows the replacement of anionic carboxylate ligands by Se22− while trapping neutral N-coordinating ligands in NiSe2 nanocrystals. Further carbonization of N-ligands embedded NiSe2 nanocrystals resulted in NiSe2@NC core-shell nano-octahedrons covered by ultrathin N-doped carbon shells. The N-species was controlled by changing N-coordinating ligands in MOF precursors, resulting in an optimized HER catalyst with a small overpotential of 162 mV at 10 mA cm−2, and good long-term stability (up to 40 h) in 1.0 M KOH solution. A strong correlation between pyridinic-N and HER activity was experimentally defined and explained by DFT calculations.

Four metal–organic complexes [Ni(HET)(phen)(H2O)]·(HET)·H2O (1), [Cu(HET)(phen)(H2O)]·1.5H2O (2), [Cu2(HET)2(bipy)1.5(H2O)]·15DMF·2H2O (3), and [Cd2O(HET)2(bipy)(H2O)]·2H2O·EtOH (4) (HET = 1,4,5,6,7,7-hexachlorobicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid, phen = 1,10-phenanthroline, bipy = 4,4′-bipyridine) have been synthesized via hydro- or solvothermal reactions. It was found that complexes 1 and 2 are two-dimensional (2D) structures built from discrete complexes via the typical intermolecular interactions, and there was a closed loop built from the lattice water and carboxylate groups in 1 through intramolecular hydrogen bonds. Complex 3 exhibits three-dimensional (3D) structure with 5-connected bnn hexagonal BN topology. Complex 4 features a non-interpenetrating sql 2D coordination network, which is further linked into a 3D structure by C–H···Cl weak interaction. The properties of magnetism, fluorescence, and electrochemistry have also been investigated in this paper.

An anionic metal-organic framework, H3[(Mn4Cl)3L8]⋅30H2O⋅2.5 DMF⋅5 Diox (UPC-15), was successfully prepared by the reaction of MnCl2 with tris(p-carboxylic acid)tridurylborane (H3 L) under solvothermal conditions. UPC-15 with wide-open pores (∼18.8 Å) is constructed by packing of octahedral and cuboctahedral cages, and exhibits high gas-sorption capabilities. Notably, UPC-15 shows selective adsorption of cationic dyes due to the anion framework. Moreover, the catalytic and magnetic properties were investigated, and UPC-15 can highly catalyze the cyanosilylation of aromatic aldehydes. UPC-15 exhibits the exchange of metal ions from Mn to Cu in a single-crystal-to-single-crystal manner to generate UPC-16, which could not be obtained by the direct solvothermal reaction of CuCl2 and H3L. UPC-16 exhibits similar properties for gas sorption, dye separation, and catalytic activity. However, the magnetic behaviors for UPC-15 and UPC-16 are distinct due to the metal-specific properties. Below 47 K, UPC-15 exhibits a ferromagnetic coupling but UPC-16 shows a dominant antiferromagnetic behavior.

In this work, the block-shaped Al-based metal–organic frameworks (Al-MOFs) MIL-53 have been synthesized by hydrothermal method. To detect the correlation between the structure of Al-MOFs and the formation of alumina, the ligands are eliminated by thermal treatment. MIL-53 and the calcination products were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), transmission electron microscopy (TEM), nitrogen adsorption–desorption and solid-state 27 Al nuclear magnetic resonance ( 27 Al NMR). It was found that after calcination, the block-shaped Al-MOFs precursor turns into high-crystallinity mesoporous alumina nanosheets, and the thermal treatment product γ -alumina possesses a dual pore system and a large surface area (146 m 2 /g), with five-fold aluminum. During the thermal treatment process, the structure of MIL-53 and its secondary building units have structure-directed effect in the formation of alumina.

Five lanthanide metal–organic frameworks, [Ln(L)(H2O)(NMP)]·1.5H2O (Ln = Ce (1), Pr (2); H3L = 1,3,5-tris(4-carboxyphenyl-1-ylmethyl)-2,4,6-trimethylbenzene), and [Ln2(L)2(H2O)3]·2H2O (Ln = Eu (3), Tm (4), Yb (5)), have been synthesized and characterized. Complexes 1–5 exhibit similar 1D channels through the linkage of Ln-carboxylate chains with the backbones of H3L ligands. The channels for complexes 1 and 2 are occupied by coordinated NMP molecules. 3 shows potential application for the luminescence sensing of small organic molecules. Moreover, 5 exhibits selective adsorption of CO2 over N2 and CH4 and catalytic activities toward the cyanosilylation reaction.

Mesoporous alumina with different morphologies was synthesized via thermal decomposition of the Al-based metal–organic frameworks (Al-MOFs) MIL-110 and MIL-100, in which Al-MOFs were used as the Al source and precursor. The hexagon rod-shaped and octahedron-shaped alumina products with morphology retained from their precursors were obtained and characterized. The results show that the construction of Al-MOFs, especially the aluminium building units plays a key role in the textural structure of the obtained alumina products. Besides, the differences in textural properties as well as the possible formation mechanism of the final alumina products are well explained by taking into account thermal behaviour and intrinsic structure features, especially the aluminium building units, of the Al-MOFs precursors. This work presents an easy new method to produce alumina with tailored morphology, tunable texture and microstructure, which is also an operational method fit for other metal oxide materials.

Three new metal–organic frameworks (MOFs) constructed from terphenyl-3,3′′,5,5′′-tetracarboxylic acid (H4ptptc) and zinc nitrate, [Zn2(ptptc)(DMF)3]·4H2O·5.5DMF (1), [Zn2(ptptc)(DMA)(H2O)]·2.5H2O·3.5DMA (2) and [Zn(ptptc)0.5(H2O)]·DMF·DMA (3), have been obtained and characterized. All the complexes exhibit 3D 4-connected networks with different topologies involving diamond (dia, for 1), lonsdaleite (lon, for 2) and Nbo (for 3), which emanate from the different reaction solvents (DMF, DMA and mixture of DMF/DMA (1 : 1), respectively). The results of photoluminescence properties show that the three complexes can be act as potential luminescent probes or sensors for detecting small organic molecules and toxic substances.

In this paper, an efficient method to fabricate Al-based metal organic framework (Al-MOF) MIL-96 crystals with controllable size and morphology, by mixing other forms of reactants to replace the coordination modulators or capping agents, is presented. The size and morphology of the MIL-96 crystals can be selectively varied by simply altering the ratio of dual reactants via their hydrolysis reaction. All the samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), Fourier Transform Infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA) and nitrogen sorption. Then based on the BFDH theory, a mechanism for the impact of hydrolysis of reactants on the crystal size and morphology is presented and discussed. We also evaluated the performance of these MOFs as sorbents for capturing CO2, and they all show enhanced adsorption properties compared with the bulk material, displaying high adsorption capacities on CO2 at atmospheric pressure and ambient temperature.

Hexagonal spindle-shaped mesoporous alumina with different internal structures were prepared using Al-based metal-organic frameworks MIL-96 as precursor through thermal treatment method. MIL-96 and alumina products were characterized by XRD, SEM, TEM, BET and TG. Results from these characterizations showed that alumina products keep the morphology of their precursor, and the thermal treatment conditions have large effect on alumina microstructures. The state of atmosphere and heating rate are the main factors affecting the internal textural properties of alumina. A possible transformation mechanism was also proposed. In addition, the effect of textural properties and structure on the adsorption ability of alumina was investigated. This work presents a novel method, which builds a direct linkage between MOF crystals and metal oxide microstructures, to control the morphology, structure and performance of alumina and other metal oxide materials.

Due to their tunable structure and porosity, metal–organic frameworks have provided a new platform for fluorescence sensing and adsorption/separation of gas or organic molecules. Many studies have focused on sensing metal ions, anions, or organic molecules through fluorescence quenching or enhancement of MOFs, but studies on pH-fluorescence sensors are seldom reported. Furthermore, highly solvent-dependent adsorption and degradation of dye molecules based on functional MOFs has not been explored to date. In this study, we describe a multifunctional Eu MOF, [H3O][Eu3(HBPTC)2(BPTC)(H2O)2]·4DMA (UPC-5, UPC = China University of Petroleum [East China]) based on a tetracarboxylate ligand. The luminescence intensity of UPC-5 is strongly correlated with the pH value in the pH range from 7.5 to 10.0, and a linear relationship between pH value and fluorescent intensity is observed. Another attractive property of UPC-5 is that its Li-exchanged form, Li-UPC-5, possesses solvent-dependent adsorption and degradation of rhodamine B. The highly efficient degradation or decolorization of rhodamine B with long-term stability and activity gives Li-UPC-5 a potential advantage in treating rhodamine B pollution.

A barium(II) metal-organic framework (MOF) based on a predesigned amino-functionalized ligand, namely [Ba

The exploration of new porous hybrid materials is of great importance because of their unique properties and promising applications in separation of materials, catalysis, etc. Herein, for the first time, by integration of metal-organic frameworks (MOFs) and covalent organic frameworks (COFs), a new type of MOF@COF core-shell hybrid material, i.e., NH2 -MIL-68@TPA-COF, with high crystallinity and hierarchical pore structure, is synthesized. As a proof-of-concept application, the obtained NH2 -MIL-68@TPA-COF hybrid material is used as an effective visible-light-driven photocatalyst for the degradation of rhodamine B. The synthetic strategy in this study opens up a new avenue for the construction of other MOF-COF hybrid materials, which could have various promising applications. NRF (Natl Research Foundation, S’pore) MOE (Min. of Education, S’pore)

This work presents the construction of a porous lead-organic framework (UPC-10) with large channels of ∼24 A. UPC-10 shows efficient adsorption of I2 and selective adsorption of some dyes containing the SO3− group. After the adsorption of dyes, UPC-10 exhibits a CO2 gas uptake ability. Furthermore, UPC-10 could be transformed into PbS in a H2S atmosphere, and the derived PbS manifests N2 and CO2 uptake abilities.

Metal-organic frameworks (MOFs) derived transition metal oxides exhibit enhanced performance in energy conversion and storage. In this work, porous hollow Co

Two 2-fold interpenetrating metal–organic frameworks based on 1,3,5-tris[2-(4-carboxyphenyl)-1-ethynyl]-2,4,6-trimethylbenzene (H3LMe), [Mn3(LMe)2(DMF)4(H2O)]·1.5DMF·3.5H2O (1) and [Cd3(LMe)2(DMF)][Cd3(LMe)2(DMF)2(H2O)]·5DMF·3.5H2O (2), have been synthesized by using rigid trigonal H3LMe and nitrate under solvothermal conditions. Complex 1 displays a three-dimensional open framework with rare (3,6)-connected 2-nodal sit topology, whereas complex 2 features a new (3,3,6)-connected topology. Both 1 and 2 are blue fluorescent, and the magnetic measurement of 1 indicates that metal centers within the trinuclear cluster exhibit antiferromagnetic coupling interactions. Significantly, although complexes 1 and 2 have similar total solvent-accessible volumes, 2 demonstrates a higher Brunauer–Emmett–Teller surface area than that of 1, further indicating the influence of pore structure on gas absorption.