The development of efficient and low‐cost bifunctional electrocatalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is highly desirable for electrochemical energy ...conversion. Herein, this study puts forward a new Co decorated N,B‐codoped interconnected graphitic carbon and carbon nanotube materials (Co/NBC) synthesized by direct carbonization of a cobalt‐based boron imidazolate framework. It is demonstrated that the carbonization temperature can tune the surface structure and component of the resultant materials and optimize the electrochemically active surface area to expose more accessible active sites, effectively boosting the electrocatalytic activity. As a result, the optimized Co/NBC shows superior bifunctional catalytic activity and stability toward OER and HER in 1.0 m KOH solution. Furthermore, the catalyst can serve as both the anode and cathode for water splitting to achieve a current density of 10 mA cm−2 at a cell voltage of 1.68 V. Experimental results and theoretical calculations indicate that the excellent activity of Co/NBC catalyst benefits from the synergistic effect of partial oxidation of metallic cobalt, conductive N,B‐codoped graphitic carbon and carbon nanotube, and the coupled interactions among these components. This work opens a promising avenue toward the exploration of boron imidazolate frameworks as efficient heteroatom‐doped catalysts for electrocatalysis.
Cobalt nanoparticles embedded in N,B‐codoped interconnected graphitic carbon and carbon nanotube (Co/NBC) are developed by direct carbonization of cobalt boron imidazolate framework as efficient bifunctional electrocatalysts for overall water splitting. Benefiting from the synergistic effects between the surface oxidation metallic cobalt and N,B‐codoped nanocarbon, the Co/NBC hybrid presents superior performance toward oxygen evolution reaction and hydrogen evolution reaction.
Grasping and assembly are essential tasks in high-precision robotic manipulation for industrial manufacturing as well as for home service applications. Many efforts have been devoted to this area in ...an attempt to meet the increasing precision requirement of the task. However, it remains a problematic objective to fulfill high precision, high reliability, high speed, and high flexibility all at once during one robotic manipulation task. To find answers to the above-mentioned problem, this article tries to categorize, review, and compare the recent works focusing on robotic grasping and assembly tasks to reveal some potential trends in this research area. The approaches will be divided into five groups based on the difference in the utilization of sensing or constraints. For each part, robotic grasping and assembly will be treated as practical cases to illustrate the concrete work in that area. This article could give the readers some knowledge on the current developments in robotic manipulation, and provide new thoughts on future direction in this area-inspiring new designs, structures, and systems to meet new requirements in applications in industrial manufacturing and home service.
Many metal–organic cages (MOCs) and a few hydrogen‐bonded organic cages (HOCs) have been investigated, but little is reported about cooperative self‐assembly of MOCs and HOCs. Herein, we describe an ...unprecedented MOC&HOC co‐crystal composed of tetrahedral Ti4L6 (L=embonate) cages and in‐situ‐generated (NH3)4(TIPA)4 (TIPA=tris(4‐(1H‐1,2,4‐triazol‐1‐yl)phenyl)amine) cages. Chiral transfer is observed from the enantiopure Ti4L6 cage to enantiopure (NH3)4(TIPA)4 cage. Two homochiral supramolecular frameworks with opposite handedness (PTC‐235(Δ) and PTC‐235(Λ)) are formed. Such MOC&HOC co‐crystal features high stability in water and other solvents, affording single‐crystal‐to‐single‐crystal transformation to trap CH3CN molecules and identify disordered NH4+ cations. A tablet pressing method is developed to test the third‐order nonlinear optical property of KBr‐based PTC‐235 thin film. Such a thin film exhibits an excellent optical limiting effect.
The supramolecular self‐assembly between metal–organic cages (MOCs) and hydrogen‐bonded organic cages (HOCs) is realized in an MOC&HOC co‐crystal composed of tetrahedral Ti4L6 cages and (NH3)4(TIPA)4 cages generated in situ. The MOC&HOC co‐crystal thin film exhibits an excellent optical limiting effect.
Copper‐based tandem catalysts with a well‐defined Cu coordination environment for the electrochemical CO2 reduction reaction (CO2RR) are highly desirable, due to their unique geometric‐electronic ...properties and helpfulness for revealing structure–property correlations. Here, this work synthesizes a tandem catalyst at atomic configuration scale, Ag@BIF‐104NSs(Cu), by using the ultrathin boron imidazolate framework (BIF) nanosheets as support to load Ag nanoparticles (NPs). Due to the highly ordered benzoate ligands decorated on the Cu sites of BIF‐104NSs(Cu), Ag NPs are located in atomic proximity to Cu sites via a coordination effect. Electrochemical CO2RR measurements show this tandem catalyst highly improves the selectivity and activity for the CO2 reduction to ethylene. The faradaic efficiency (FEC2H4) of 21.43% is significantly higher than that of BIF‐104NSs(Cu) (3.82%). Further, density functional theory calculations reveal that the Ag sites in the composite can efficiently reduce CO2 to *CO, that subsequently migrate to the Cu sites. Thereafter, the Cu–Ag atom pair is responsible for the C–C coupling of the local enriched *CO and further formation of C2H4.
A copper‐silver tandem catalyst is synthesized at atomic configuration scale, by using the ultrathin boron imidazolate framework (BIF) nanosheets as support to load Ag nanoparticles (NPs). Ag@BIF‐104NSs(Cu) shows higher catalytic activity and selectivity for C2H4 than BIF‐104NSs(Cu), because the Cu–Ag atom pair can effectively enhance the C–C coupling of the local enriched *CO from Ag sites.
The hydrolysis of earth‐abundant AlIII has implications in mineral mimicry, geochemistry and environmental chemistry. Third‐order nonlinear optical (NLO) materials are important in modern chemistry ...due to their extensive optical applications. The assembly of AlIII ions with π‐conjugated carboxylate ligands is carried out and the hydrolysis and NLO properties of the resultant material are studied. A series of Al32‐oxo clusters with hydrotalcite‐like cores and π‐conjugated shells are isolated. X‐ray diffraction revealed boundary hydrolysis occurs at the equatorially unsaturated coordination sites of AlIII ions. Charge distribution analysis and DFT calculations support the proposed boundary substitution. The Al32‐oxo clusters possess a significant reverse saturable absorption (RSA) response with a minimal normalized transmittance up to 29 %, indicating they are suitable candidates for optical limiting (OL) materials. This work elucidates the hydrolysis of AlIII and provides insight into layered materials that also have strong boundary activity at the edges or corners.
A series of Al32‐oxo clusters with hydrotalcite‐like cores and π‐conjugated shells were isolated, which are unique models of two‐dimensional or layered materials and may be used to study boundary activity and optical limiting properties.
Making oppositely charged metal‐organic cages (MOCs) into a tightly ordered structure may bring interesting functions. Herein, we report a novel structure composed of anionic (Zr4L6)8− (L=embonate) ...tetrahedral cages and in situ‐formed cationic Zn4(Bim)44+ (Bim=BH(im)3−; im=imidazole) cubic cages. Chiral transfer is observed from enantiopure (Zr4L6)8− cage to enantiopure Zn4(Bim)44+ cage. A pair of enantiomers (PTC‐373(Δ) and PTC‐373(Λ)) are formed. PTC‐373 exhibits high chemical and thermal stabilities, affording an interesting single‐crystal‐to‐single‐crystal transformation. More importantly, the combination of ionic pair cages significantly enhances its third‐order nonlinear optical property, and its thin‐film exhibits an excellent optical limiting effect.
Making anionic zirconium‐organic cage and cationic boron‐imidazolate cage into a tightly ordered structure achieves an efficient optical limiting response.
Pore size plays a critical role in determining the performance of metal‐organic frameworks (MOFs) in catalysis, sensing, and gas storage or separation. However, revealing the pore‐size/property ...relationship remains extremely challenging because ideal structure models possessing different pore sizes but having the same components are lacking. In this work, a solvent‐coordination directed structure swelling method was developed for modulating the ratio between the large and narrow pore phases of a flexible MOF, MIL‐88B. Pore‐size‐dependent gas sensitivity and selectivity were studied for the first time in the MIL‐88B samples. The optimized MIL‐88B‐20 % sample showed one of the best sensing performances among all the reported MOF‐based H2S‐sensing materials. This work not only provides a method to synthesize ideal structure models for revealing the relationship between pore‐size and properties, but also may inspire the development of high‐performance gas sensing materials.
The solvent‐coordination directed structure swelling method was used to modulate the pore size of MIL‐88B, which enables to reveal the pore‐size‐dependent gas sensitivity and selectivity of MOF materials for the first time.
Abstract
Regulating nonlinear optical (NLO) property of metal−organic frameworks (MOFs) is of pronounced significance for their scientific research and practical application, but the regulation ...through external stimuli is still a challenging task. Here we prepare and electrically control the nonlinear optical regulation of conductive MOFs Cu-HHTP films with 001- (Cu-HHTP
001
) and 100-orientations (Cu-HHTP
100
). Z-scan results show that the nonlinear absorption coefficient (
β
) of Cu-HHTP
001
film (7.60 × 10
−6
m/W) is much higher than that of Cu-HHTP
100
film (0.84 × 10
−6
m/W) at 0 V and the
β
of Cu-HHTP
001
and Cu-HHTP
100
films gradually increase to 3.84 × 10
−5
and 1.71 × 10
−6
m/W at 10 V by increasing the applied voltage, respectively. Due to 2D Cu-HHTP having anisotropy of charge transfer in different orientations, the NLO of MOFs film can be dependent on their growth orientations and improved by tuning the electrical field. This study provides more avenues for the regulation and NLO applications of MOFs.
The construction of hydrophobic nanochannel with hydrophilic sites for bionic devices to proximally mimick real bio‐system is still challenging. Taking the advantages of MOF chemistry, a highly ...oriented CuTCPP thin film has been successfully reconstructed with ultra‐thin nanosheets to produce abundant two‐dimensional interstitial hydrophobic nanochannels with hydrophilic sites. Different from the classical active‐layer material with proton transport in bulk, CuTCPP thin film represents a new type of active‐layer with proton transport in nanochannel for bionic proton field‐effect transistor (H+‐FETs). The resultant device can reversibly modulate the proton transport by varying the voltage on its gate electrode. Meanwhile, it shows the highest proton mobility of ≈9.5×10−3 cm2 V−1 s−1 and highest on‐off ratio of 4.1 among all of the reported H+‐FETs. Our result demonstrates a powerful material design strategy for proximally mimicking the structure and properties of bio‐systems and constructing bionic electrical devices.
A MOF thin film‐based bionic proton field‐effect transistor (H+‐FET) has been fabricated for the first time. It displays the highest proton mobility and highest on–off ratio among all reported H+‐FETs.
Porous organic polymers (POPs) with high porosity and tunable functionalities have been widely studied for use in gas separation, catalysis, energy conversion and energy storage. However, the high ...cost of organic monomers, and the use of toxic solvents and high temperatures during synthesis pose obstacles for large‐scale production. Herein, we report the synthesis of imine and aminal‐linked POPs using inexpensive diamine and dialdehyde monomers in green solvents. Theoretical calculations and control experiments show that using meta‐diamines is crucial for forming aminal linkages and branching porous networks from 2+2 polycondensation reactions. The method demonstrates good generality in that 6 POPs were successfully synthesized from different monomers. Additionally, we scaled up the synthesis in ethanol at room temperature, resulting in the production of POPs in sub‐kilogram quantities at a relatively low cost. Proof‐of‐concept studies demonstrate that the POPs can be used as high‐performance sorbents for CO2 separation and as porous substrates for efficient heterogeneous catalysis. This method provides an environmentally friendly and cost‐effective approach for large‐scale synthesis of various POPs.
Porous organic polymers (POPs) with high surface areas were synthesized using inexpensive diamine and dialdehyde monomers under green synthesis conditions. Sub‐kilogram yields of POP were obtained from a scaled‐up synthesis in ethanol at room temperature. The cost of POPs can be reduced to ≈10 USD/kg, making it significantly more cost‐effective compared to other porous materials.
