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Pore space partitioning (PSP) is methodically suited for dramatically increasing the density of guest binding sites, leading to the partitioned acs (pacs) platform capable of record-high uptake for CO

A multi-stage core-expansion method is proposed here as one component of the integrative binding-site/extender/core-expansion (BEC) strategy. The conceptual deconstruction of the partitioning ligand into three editable parts draws our focus onto progressive core expansion and allows the optimization of both acetylene uptake and selectivity. The effectiveness of this strategy is shown through a family of eight cationic pore-partitioned materials containing three different partitioning ligands and various counter anions. The optimized structure, Co3-cpt-tph-Cl (Hcpt = 4-(p-carboxyphenyl)-1,2,4-triazole, H-tph = (2,5,8-tri-(4-pyridyl)-1,3,4,6,7,9-hexaazaphenalene) with the largest surface area and highest C2H2 uptake capacity (200 cm3/g at 298 K), also exhibits (desirably) the lowest CO2 uptake and hence the highest C2H2/CO2 selectivity. The successful boost in both C2H2 capacity and IAST selectivity allows Co3-cpt-tph-Cl to rank among the best crystalline porous materials, ionic MOFs in particular, for C2H2 uptake and C2H2/CO2 experimental breakthrough separation.

We report here a one-step method for synthesizing multi-component and in-situ-formed homochiral spiroborate-ester-based metal-organic framework CPM-B1. This unique material successfully integrates COF fragment spiroborate ester within the MOF and simultaneously incorporate homochirality and helicity. In addition, CPM-B1 is a rare example of framework materials that results from the cooperative assembly of three charge-complementary cations: +1 (lithium), +2 (cobalt), and +3 (boron). The sophistication of the co-assembly is further highlighted by the three structural roles of lithium ions. This unique structure contributes to its multi-functional properties such as ionic conductivity and catalytic activity for oxygen reduction reaction (by CPM-B1 carbonized material) and provides a new path to develop MOF materials with complex secondary building units and multi-functional applications.

The development of effective propane (C3H8)-selective adsorbents for the purification of propylene (C3H6) from C3H8/C3H6 mixture is a promising alternative to replace the energy-intensive cryogenic distillation. However, few materials possess the dual desirable features of propane selectivity and high uptake capacity. Here, we report a family of pore-space-partitioned crystalline porous materials (CPM) with remarkable C3H8 uptake capacity (up to 10.9 mmol/g) and the highly desirable yet uncommon C3H8 selectivity (up to 1.54 at 0.1 bar and 1.44 at 1 bar). The selectivity-capacity synergy endows them with record-performing C3H8/C3H6 separation potential (i.e., C3H6 recovered from the mixture). Moreover, these CPMs exhibit outstanding properties including high stability, low regeneration energy, and multimodular chemical and geometrical tunability within the same isoreticular framework. The high C3H8/C3H6 separation performance was further confirmed by the breakthrough experiments.

Two new rod-packing metal-organic frameworks (RPMOF) are constructed by regulating the in situ formation of the capping agent. In CPM-s7, carboxylate linkers extend 1D manganese-oxide chains in four additional directions, forming 3D RPMOF. The substitution of Mn

We report a family of carbon materials (denoted SFZ8C) prepared from templated carbonization of zeolitic imidazolate framework-8 (ZIF-8) in NaCl–ZnCl2 eutectic salt. The hard-templating effect of the salt is utilized to sustain the framework and maximize the porosity during carbonization. In addition to rich surface nitrogen and oxygen species, SFZ8Cs have large specific surface area. These combined features give rise to excellent adsorption properties for light hydrocarbon gases. SFZ8Cs have both C2H2/CO2 selective and C3/C2 selective adsorption, as well as the ability to selectively remove impurities from methane. Particularly noteworthy is the excellent C3/C2 selective adsorption performance by SFZ8C-900. Its propane/ethane selectivity (7.68) is on par with the best value (7.72) reported so far, yet SFZ8C-900 excels in propane uptake capacity. The multifunctional properties together with the ease for the mass production make SFZ8Cs promising for a number of important applications.

For rare-earth separation, selective crystallization into metal-organic frameworks (MOFs) offers new opportunities. Especially important is the development of MOF platforms with high selectivity toward target ions. Here we report a MOF platform (CPM-66) with low-coordination-number environment for rare-earth ions. This platform is highly responsive to the size variation of rare-earth ions and shows exceptional ion-size selectivity during crystallization. CPM-66 family are based on M3 O trimers (M=6-coordinated Sc, In, Er-Lu) that are rare for lanthanides. We show that the size matching between urea-type solvents and metal ions is crucial for their successful synthesis. We further show that CPM-66 enables a dramatic multi-fold increase in separation efficiency over CPM-29 with 7-coordinated ions. This work provides some insights into methods to prepare low-coordinate MOFs from large ions and such MOFs could serve as high-efficiency platforms for lanthanide separation, as well as other applications.

The oxygen evolution reaction (OER) is a critical electrochemical reaction in water splitting and rechargeable metal–air batteries. It plays a pivotal role in achieving high-efficiency clean-energy production and energy storage in these devices. Transition metal-based bimetallic MOFs (TMB MOFs) with two different metal ions possess specific synergistic effects, which could exhibit OER performance and stability superior to those of the corresponding monometallic MOFs for water oxidation. Benefiting from the diversity of chemical composition and structural type, TMB MOFs can also serve as precursors and templates to obtain alloy-particle-decorated carbon materials with high surface area, or metal compounds such as bimetallic sulfides, phosphides, and hydroxides with atomic-level mixing of heterometallic elements. These materials with high-density active sites exhibit much improved catalytic activity in the water oxidation reaction. This article aims to review the recent progress with TMB MOFs and their derivatives in relation to applications as electrocatalysts in OER, including analysis of the mechanism of the OER process with the assistance of DFT calculations and in situ or operando techniques.

We report here a strategy for making anionic pacs type porous materials by combining pore space partition with charge reallocation. The method uses the first negatively charged pore partition ligand (2,5,8-tri-(4-pyridyl)-1,3,4,6,7,9-hexaazaphenalene, H-tph) that simultaneously enables pore partition and charge reallocation. Over two dozen anionic pacs materials have been made to demonstrate their excellent chemical stability and a high degree of tunability. Notably, Ni

Integrating different types of fundamental chemical interactions to direct the self-assembly processes and to control the dimension of the network formed by each type of interactions is a promising...

Introduction of pore partition agents into hexagonal channels of MIL-88 type (acs topology) endows materials with high tunability in gas sorption. Here, we report a strategy to partition acs framework into pacs (partitioned acs) crystalline porous materials (CPM). This strategy is based on insertion of in situ synthesized 4,4'-dipyridylsulfide (dps) ligands. One third of open metal sites in the acs net are retained in pacs MOFs; two thirds are used for pore-space partition. The Co2 V-pacs MOFs exhibit near or at record high uptake capacities for C2 H2 , C2 H4 , C2 H6 , and CO2 among MOFs. The storage capacity of C2 H2 is 234 cm3 g-1 (298 K) and 330 cm3 g-1 (273 K) at 1 atm for CPM-733-dps (the Co2 V-BDC form, BDC=1,4-benzenedicarboxylate). These high uptake capacities are accomplished with low heat of adsorption, a feature desirable for low-energy-cost adsorbent regeneration. CPM-733-dps is stable and shows no loss of C2 H2 adsorption capacity following multiple adsorption-desorption cycles.

Here, we report a double-bent-ligand strategy which addresses a commonly encountered challenge in the construction of pillar-layered structures with corrugated layers which are common for nonlinear...

An ideal material for C2H6/C2H4 separation would simultaneously have the highest C2H6 uptake capacity and the highest C2H6/C2H4 selectivity. But such material is elusive. A benchmark material for ethane-selective C2H6/C2H4 separation is peroxo-functionalized MOF-74-Fe that exhibits the best known separation performance due to its high C2H6/C2H4 selectivity (4.4), although its C2H6 uptake capacity is moderate (74.3 cm3/g). Here, we report a family of pore-space-partitioned crystalline porous materials (CPMs) with exceptional C2H6 uptake capacity and C2H6/C2H4 separation potential (i.e., C2H4 recovered from the mixture) despite their moderate C2H6/C2H4 selectivity (up to 1.75). The ethane uptake capacity as high as 166.8 cm3/g at 1 atm and 298 K, more than twice that of peroxo-MOF-74-Fe, has been achieved even though the isosteric heat of adsorption (21.9-30.4 kJ/mol) for these CPMs is as low as about one-third of that for peroxo-MOF-74-Fe (66.8 kJ/mol). While the overall C2H6/C2H4 separation potentials have not yet surpassed peroxo-MOF-74-Fe, these robust CPMs exhibit outstanding properties including high thermal stability (up to 450 °C) and aqueous stability, low regeneration energy, and a high degree of chemical and geometrical tunability within the same isoreticular framework.

Low-cost Ni(OH)2-based nanomaterials with various structures and morphologies are promising catalysts for efficient oxygen evolution reactions (OERs). However, homogenous Ni(OH)2 nanomaterials with abundant active sites suffer from low conductivity and easy aggregation, resulting in low catalytic activity and stability. Here, we report a new synthetic method capable of generating abundant and confined S-doped β-Ni(OH)2 nanoparticles (NPs) (3–5 nm) within a 3D semiconductor substrate, metal-chalcogenide semiconductor zeolite (CSZ). This method operates via sequential fluoride-assisted cationic stripping and in situ Ni(OH)2 generation and is demonstrated here as an effective method to synthesize Ni2+-containing CSZ that are known to defy direct synthesis. The resulting composite (denoted Ni(OH)2 NPs@CSZ) exhibited excellent OER performance with a very low overpotential of only 212 mV at a current density of 10 mA cm−2 in O2-saturated 1 M KOH solution, and low Tafel slope of 64.2 mV dec−1, which is superior to that of benchmark IrO2. DFT calculations indicate that the interaction between the embedded Ni(OH)2 NPs and the dopant, S2−, from the host CSZ played a crucial role in improving OER performance. This work provides a new path for developing high-performance Ni(OH)2-based OER catalysts and may also serve as a general approach for loading large amounts of other catalytically active NPs into semiconducting open frameworks to further optimize electrocatalytic performance.

Zeolitic imidazolate frameworks (ZIFs) are traditionally synthesized solvothermally by using cost- and waste-incurring organic solvents. Here, a direct synthesis method is reported for ZIF-8, ZIF-67, and their heterometallic versions from solid precursors only. This solvent-free crystallization method not only completely avoids organic solvents, but also provides an effective path for the synthesis of homogeneous mixed-metal ZIFs. Furthermore, under templating by NaCl/ZnCl2 eutectic salt, carbonization of the ZIF materials gives rise to a series of N-containing high-surface-area carbon materials with impressive catalytic properties for the oxygen reduction reaction.

A new perspective is proposed in the design of pore-space-partitioned MOFs that is focused on ligand symmetry properties sub-divided here into three hierarchical levels: 1) overall ligand, 2) ligand substructure such as backbone or core, and 3) the substituent groups. Different combinations of the above symmetry properties exist. Given the close correlation between nature of chemical moiety and its symmetry, such a unique perspective into ligand symmetry and sub-symmetry in MOF design translates into the influences on MOF properties. Five new MOFs have been prepared that exhibit excellent hydrothermal stability and high-performance adsorption properties with potential applications such as C

State-of-the-art MOFs are generally known for chemical stability at one end of the pH scale (i.e., pH 14). Herein, we report new Cr-MOFs capable of withstanding extreme pH conditions across approximately 16 pH units from pH 14, likely the largest observed pH range for MOFs. The integration of multiple stability-enhancing factors including nonlabile Cr3+, mixed Cr-N and Cr-O cross-links, and the highest possible connectivity by Cr3O trimers enables extraordinary chemical stability confirmed by both PXRD and gas adsorption. Notably, the base stability is much higher than literature Cr-MOFs, thereby revitalizing Cr-MOF's viability in the pursuit for the most chemically stable MOFs. Among known cationic MOFs, the chemical stability of these new Cr-MOFs is unmatchable, to our knowledge. These Cr-MOFs can be developed into multiseries of isoreticular MOFs with a rich potential for functionalization, pore size, and pore geometry engineering and applications.

Metal chalcogenide supertetrahedral clusters (MCSCs) are of significance for developing crystalline porous framework materials and atomically precise cluster chemistry. Early research interest focused on the synthetic and structural chemistry of MCSC-based porous semiconductor materials with different cluster sizes/compositions and their applications in adsorption-based separation and optoelectronics. More recently, focus has shifted to the cluster chemistry of MCSCs to establish atomically precise structure–composition–property relationships, which are critical for regulating the properties and expanding the applications of MCSCs. Importantly, MCSCs are similar to II–VI or I–III–VI semiconductor nanocrystals (also called quantum dots, QDs) but avoid their inherent size polydispersity and structural ambiguity. Thus, discrete MCSCs, especially those that are solution-processable, could provide models for understanding various issues that cannot be easily clarified using QDs. This review covers three decades of efforts on MCSCs, including advancements in MCSC-based open frameworks (reticular chemistry), the precise structure–property relationships of MCSCs (cluster chemistry), and the functionalization and applications of MCSC-based microcrystals. An outlook on remaining problems to be solved and future trends is also presented., The development of metal chalcogenide supertetrahedral clusters over the past three decades was concentrated in this review, ranging from the construction of cluster-based frameworks to the exploration of atomically precise cluster chemistry.

Embedding cubane [M4 (OH)4 ] (M=Ni, Co) clusters within the matrix of metal-organic frameworks (MOFs) is a strategy to develop materials with unprecedented synergistic properties. Herein, a new material type based on the pore-space partition of the cubic primitive minimal-surface net (MOF-14-type) has been realized. CTGU-15 made from the [Ni4 (OH)4 ] cluster not only has very high BET surface area (3537 m2 g-1 ), but also exhibits bi-microporous features with well-defined micropores at 0.86 nm and 1.51 nm. Furthermore, CTGU-15 is stable even under high pH (0.1 m KOH), making it well suited for methanol oxidation in basic medium. The optimal hybrid catalyst KB&CTGU-15 (1:2) made from ketjen black (KB) and CTGU-15 exhibits an outstanding performance with a high mass specific peak current of 527 mA mg-1 and excellent peak current density (29.8 mA cm-2 ) at low potential (0.6 V). The isostructural cobalt structure (CTGU-16) has also been synthesized, further expanding the application potential of this material type.

We report a new magnesium metal-organic framework (MOF) (CPM-107) with a special interaction with CO2 . CPM-107 contains Mg2 -acetate chains crosslinked into a 3D net by terephthalate. It has an anionic framework encapsulating ordered extra-framework cations and solvent molecules. The desolvated form is closed and unresponsive to common gasses, such as N2 , H2 , and CH4 . Yet, with CO2 at 195 K, it abruptly opens and turns into a rigid porous form that is irreversible via desorption. Once opened by CO2 , CPM-107 remains in the stable porous state accessible to additional gas types over multiple cycles or CO2 itself at different temperatures. The porous phase can be re-locked to return to the initial closed phase via re-solvation and desolvation. Such peculiar properties of CPM-107 are apparently linked to a convergence of factors related to both framework and extra-framework features. The unusual CO2 effect is currently the only available path to porous CPM-107 which shows efficient C2 H2 /CO2 separation.

The creation of new cluster building blocks, as well as new ligand coordination modes, are among the most effective ways to develop new framework materials. Yet, large and chiral clusters are both difficult to create and relatively few. Here, by studying the competing coordination of different azolates against carboxylate and combined carboxylate/phenolate, it is shown that the impact of azolates in the MOF-74 synthesis system differs dramatically, leading to the synthesis of MOF-74, UTSA-74, and CPM-72 for 2-methylimidazole, 1,2,4-triazole, and 1,2,3-triazole, respectively. The new CPM-72 contains a novel chiral Zn12 triazolate cluster, which features a trigonal-prismatic Zn6 core inside an octahedral Zn6 shell. In contrast with MOF-74 with fully deprotonated and symmetrically bonded 2,5-dihydroxyterephthalic acid (H4 DOBDC), H4 DOBDC adopts an unusual nonsymmetric bonding mode in CPM-72 (carboxylate only at one end and carboxylate/phenolate at the other), resulting in a highly porous and intrinsically chiral 3D framework. The nonsymmetric bonding mode by H4 DOBDC, apparently dictated by the chiral Zn12 cluster, can be replicated with 2-hydroxyterephthalic acid (H3 OBDC), leading to the synthesis of porous isoreticular CPM-73.

The integration of heterometallic units and nanostructures into metal-organic frameworks (MOFs) used for the oxygen evolution reaction (OER) can enhance the electrocatalytic performance and help elucidate underlying mechanisms. We have synthesized a series of stable MOFs (CTGU-10a1-d1) based on trinuclear metal carboxylate clusters and a hexadentate carboxylate ligand with a (6,6)-connected nia net. We also present a strategy to synthesize hierarchical bimetallic MOF nanostructures (CTGU-10a2-d2). Among these, CTGU-10c2 is the best material for the OER, with an overpotential of 240 mV at a current density of 10 mA cm-2 and a Tafel slope of 58 mV dec-1 . This is superior to RuO2 and confirms CTGU-10c2 as one of the few known high-performing pure-phase MOF-OER electrocatalysts. Notably, bimetallic CTGU-10b2 and c2 show an improved OER activity over monometallic CTGU-10a2 and d2. Both DFT and experiments show that the remarkable OER performance of CTGU-10c2 is due to the presence of unsaturated metal sites, a hierarchical nanobelt architecture, and the Ni-Co coupling effect.

The [Zn4O]6+ cluster is well-known to form the archetypal MOF-5 topology with dicarboxylate ligands. Here we report two new materials (CPM-300 and -301) that show dramatic alteration of topological and chemical behaviors of [Zn4O]6+ clusters. In CPM-300, [Zn4O]6+ untypically forms the MIL-88/MOF-235 type framework with a small pentane-ring-based chiral dicarboxylate. In contrast, in CPM-301, when mediated by [Zn9(btz)12]6+ clusters (btz = benzotriazolate), the MOF-5 topology is regenerated with the same chiral ligand, albeit with alternating [Zn4O]6+ and [Zn9(btz)12]6+ clusters. Importantly, both CPM-300 and CPM-301 are homochiral, hydrothermally stable in boiling water and alcohol, and thermally stable to 440 °C or higher. It is concluded that small methyl groups on the chiral ligand is sufficiently powerful to shield [Zn4O]6+ clusters from degradation by water, even at high temperatures. These results reveal a promising platform for the development of a new class of cluster-based homochiral and hydrothe...

ConspectusMetal chalcogenide supertetrahedral clusters (MCSCs) bear the closest structural resemblance to II-VI or I-III-VI semiconductor nanocrystals and can be considered as well-defined ultrasmall "quantum dots" (QDs). Compared to traditional colloidal QDs that are typically associated with size dispersity, irregular surface atomic structures, poorly defined core-ligand interfaces, and random defect/dopant sites, the nano- or subnano-sized MCSCs feature precise structural properties such as atomically uniform size, precise structure, and ordered dopant distribution, all of which offer ample opportunities for a broad and in-depth understanding of the correlation between the precise local structure and site- or size-dependent properties, which are critical to the exploitation of their functional applications. Our previous Account in 2005 provided a narrative on the efforts to expand the structural diversity of open-framework materials using different-sized and compositionally tunable clusters as building blocks with a primary objective of integrating the semiconducting properties with porosity in zeolite-type solids. Over the past 15 years, significant progress has been made, particularly in the synthetic control of discrete clusters, allowing the establishment of the composition-structure-property correlation of the MCSCs to guide the optimization of their properties for various applications. In the present Account, the recent progress in MCSC-based chemistry is reviewed from three aspects: (1) controllable synthesis of new members and types of MCSC models and the development of organic-ligand-directed hybrid assembly modes for MCSC-based open frameworks; (2) new synthetic strategies for the discretization of MCSCs in crystal lattice and their dispersibility in solvents, affording practical applications of pure inorganic MCSCs as nanomaterials; and (3) functionality of MCSC-based materials including photochemical and electrochemical properties triggered by precise dopant/defect sites, open-framework-related functional expansion via host-guest chemistry, and dispersed cluster-based composite materials with synergy from functional multimetallic components. All these advances show that MCSCs with well-defined structures and atomically precise dopant/defect sites are powerful model systems for establishing the precise structure-composition-property correlation and understanding the photophysical dynamic behaviors, both of which are difficult or impossible to achieve in the traditional QD system. Perspectives on their potential applications are presented in terms of the amorphous assemblies of monodispersed MCSCs, MCSC-based two-dimensional layered materials, and optical/electronic devices.

High gas‐uptake capacity is desirable for many reasons such as gas storage and sequestration. Moreover, ultrahigh capacity can enable a practical separation process by mitigating the selectivity factor that sometimes compromises separation efficiency. Herein, a single‐walled nickel–organic framework with an exceptionally high gas capture capability is reported. For example, C2H4 and C2H6 uptake capacities are at record‐setting levels of 224 and 289 cm3 g−1 at 273 K and 1 bar (169 and 110 cm3 g−1 at 298 K and 1 bar), respectively. Such ultrahigh capacities for both gases give rise to an excellent separation performance, as shown for C2H6/C2H4 with breakthrough times of 100, 60 and 30 min at 273, 283 and 298 K and under 1 atm. This new material is also shown to readily remove ethylene released from fruits, and once again, its ultrahigh capacity plays a key role in the extraordinary length of time achieved in the preservation of the fruit freshness., Long live bananas! A stable nickel metal–organic framework with a voracious and unsurpassed appetite for ethane can also perform direct air capture of ethylene to keep bananas going on and on.

Metal trimers [M3 (O/OH)](OOCR)6 are among the most important structural building blocks. From these trimers, a great success has been achieved in the design of 6- or 9-connected framework materials with various topological features and outstanding gas-sorption properties. In comparison, 8-connected trimer-based metal-organic frameworks (MOFs) are rare. Given multiple competitive pathways for the formation of 6- or 9-connected frameworks, it remains challenging to identify synthetic or structural parameters that can be used to direct the self-assembly process toward trimer-based 8-connected materials. Here, a viable strategy called angle bending modulation is revealed for creating a prototypical MOF type based on 8-connected M3 (OH)(OOCR)5 (Py-R)3 trimers (M = Zn, Co, Fe). As a proof of concept, six members in this family are synthesized using three types of ligands (CPM-80, -81, and -82). These materials do not possess open-metal sites and show excellent uptake capacity for various hydrocarbon gas molecules and inverse C2 H6 /C2 H4 selectivity. CPM-81-Co, made from 2,5-furandicarboxylate and isonicotinate, features selectivity of 1.80 with high uptake capacity for ethane (123 cm3 g-1 ) and ethylene (113 cm3 g-1 ) at 298 K and 1 bar.

Although many rod-packing metal-organic frameworks are known, few are based on ordered heterometallic rod building unit. We show here the synthesis of CPM-76 based on an unprecedented Zn-Mg bimetallic rod with crystallographically distinguishable metal sites. The configuration of the rod offers two types of coordination site with trigonal bipyramidal and octahedral sites selectively occupied by Zn and Mg, respectively. Also unusual is the inter-connection mode between the rods, which is based on dual-charged forms (-3 and -2) of the 2-hydroxyterephthalic acid (H3 OBDC) ligand. Interestingly, each metal site in CPM-76 binds one solvent molecule, leading to a high density of solvent binding sites.

Synthetic design and construction of P–N heterojunctions are attracting increasing attention due to their potential applications such as in catalysis, gas sensors, and energy storage and conversion...

Homochiral metal-organic frameworks (MOFs) are an important class of chiral solids with potential applications in chiral recognition; however, relatively few are available. Of great importance is the availability of low-cost, racemization-resistant, and versatile enantiopure building blocks. Among chiral building blocks, d-camphoric acid is highly prolific, yet, its trans-isomer, l-isocamphoric acid, has remained unknown in the entire field of solid-state materials. Its rich yet totally untapped synthetic and structural chemistry has now been investigated through the synthesis of a large family of homochiral metal isocamphorates. The first observation of diastereoisomerism in isostructural MOFs is presented. Isocamphorate has a powerful ability to create framework topologies unexpected from common inorganic building blocks, and isocamphoric acid should allow access to hundreds of new homochiral materials.

A facile and general strategy is presented to create well-defined heterojunctions with ultra-small multimetallic sulfide nanoparticles (MMSNPs) uniformly coated on sliver nanowires. A unique aspect of this method is the atomic-level pre-integration of multimetallic components by exploiting recently developed supertetrahedral metal sulfide nanoclusters. The use of such nanoclusters also enables the convenient formation of the ultrathin interfacial Ag2 S layer via etching. The heterojunctions (denoted as MMSNPs/Ag2 S/Ag-NWs) benefit from adjustable multimetallic components and display tunable visible-light-driven photocatalytic performance owing to the synergistic effect of multimetallic components from MMSNPs and the high carrier mobility of Ag-NWs. The synthetic strategy opens new routes to designing and fabricating various heterojunctions with multimetallic components, which could further expand their applications in catalysis, electronics, and photonics.

A new strategy for creating homochiral metal-organic frameworks through a fusion of pillaring and templating concepts is demonstrated. This strategy makes use of the synergy among various chemical interactions during self-assembly processes, and leads to the synthesis of a series of homochiral frameworks. In the presence of only pillar-to-pillar π-π interactions, inter-pillar forces compete against metal-pillar interactions, resulting in mismatch between pillar-to-pillar and metal-to-metal separations and consequently 2D materials without pillaring. To create 3D materials, a method was developed to use various aromatic molecules, polycyclic aromatic hydrocarbons in particular, as templates to modulate the inter-pillar interaction and separation, leading to the formation of 3D homochiral frameworks. The use of aromatic molecules, especially hydrocarbons, as structure-directing agents, represents a new approach in the development of crystalline porous materials. Aromatic templates can be post-synthetically extracted to yield flexible porous homochiral materials with gate-opening gas sorption behaviors for both N2 and CO2 at partial pressures tunable by temperature.

Inter-ligand van der Waals forces play a key role in the synthesis of different ZIF types. Here we report an unusual case involving covalent inter-ligand interactions through disulfide bond formation in a ZIF-8 analogue. It exhibits high CO2 uptake and stepwise adsorption of light hydrocarbons with potential applications in ethane/ethylene separation.

We report here the intrinsic advantages of a special family of porous chalcogenides for CO2 adsorption in terms of high selectivity of CO2/N2, large uptake capacity, and robust structure due to their first-ever unique integration of the chalcogen-soft surface, high porosity, all-inorganic crystalline framework, and the tunable charge-to-volume ratio of exchangeable cations. Although tuning the CO2 adsorption properties via the type of exchangeable cations has been well-studied in oxides and MOFs, little is known about the effects of inorganic exchangeable cations in porous chalcogenides, in part because ion exchange in chalcogenides can be very sluggish and incomplete due to their soft character. We have demonstrated that, through a methodological change to progressively tune the host–guest interactions, both facile and nearly complete ion exchange can be accomplished. Herein, a series of cation-exchanged zeolitic chalcogenides (denoted as M@RWY) were studied for the first time for CO2 adsorption. Samples...

Detecting formaldehyde at low operating temperature and maintaining long-term stability are of great significance. In this work, a hierarchical Co3O4 nanostructure has been fabricated by calcining Co5-based metal–organic framework (MOF) microcrystals. Co3O4-350 particles were used for efficient gas-sensing for the detecting of formaldehyde vapor at lower working temperature (170 °C), low detection limit of 10 ppm, and long-term stability (30 days), which not only is the optimal value among all reported pure Co3O4 sensing materials for the detection of formaldehyde but also is superior to that of majority of Co3O4-based composites. Such extraordinarily efficient properties might be resulted from hierarchically structures, larger surface area and unique pore structure. This strategy is further confirmed that MOFs, especially Co-clusters MOFs, could be used as precursor to synthesize 3D nanostructure metal oxide materials with high-performance, which possess high porosity and more active sites and shorter io...

The development of novel photocatalysts usually centers on features such as band structures, various nano-, micro-, or macro-forms, and composites in efforts to tune their light absorption and charge separation efficiency. In comparison, the selectivity of photocatalysts with respect to features of reactants such as size and charge has received much less attention, in part due to the difficulty in designing semiconducting photocatalysts with uniform pore size. Here, we use crystalline porous chalcogenides as a platform to probe reactant selectivity in photocatalytic processes. The 3-in-1 integration of high surface area, uniform porosity, and favorable band structures in such chalcogenides makes them excellent candidates for efficient and selective photocatalytic processes. We show that their photocatalytic activity and selectivity are closely related to their differing affinity and selectivity for different guest species. In particular, unlike common solid-state photocatalysts with neutral framework, the anionic nature of the porous chalcogenide framework used here endows them with a high degree of selectivity for cationic species in both guest exchange and closely coupled photocatalytic transformation of such guests. Another interesting discovery is the observation of an unusual ion exchange process involving a transient state of over-saturation of exchanged ions, which can be explained by a transition from an initially kinetically controlled process to a subsequent thermodynamically controlled one. This work is part of ongoing efforts to contribute to the development of a new generation of crystalline porous photocatalysts with custom-designed selectivity for various reactants or products.