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Iron‐based catalysts play an important role in the ammonia industry. As one of the most abundant iron minerals, Fe3O4 containing FeII and FeIII sites is widely distributed in the earth's crust and even on exoplanets, theoretically giving it both economic and catalytic potentials in ammonia synthesis. However, in the absence of specific active co‐catalyst and harsh conditions, Fe3O4 is impossible to achieve ammonia synthesis alone. Here, we designed to activate the relatively inert FeII and FeIII sites in Fe3O4 with a third FeIII site inlayed in a coordination framework (MIL‐101(Fe)) to achieve the unpresented multi‐site collaborative catalysis. In‐depth mechanism study confirmed the roles of three different Fe sites in N2 activation, H2 activation, and product transfer, respectively. Efficient N2−H2 activation to NH3 on the Fe3O4‐based catalytic system has been achieved at extremely mild conditions. Our research provides a theoretical basis and a new strategy for designing efficient non‐noble metal‐based ammonia synthesis catalyst with minimized energy consumption. [ABSTRACT FROM AUTHOR]

As a biodegradable and biocompatible polymer material, polyglycolic acid is attracting more and more attention in the field of polymeric and biomedical materials. Consequently, the study of the transformation between different crystal forms of glycolide, the monomer of polyglycolic acid, is of great importance, because crystal forms of glycolide determine the stabilities and properties of polyglycolic acid products polymerized under different conditions in industry. Herein, this article reports the synthesis and crystallization of α‐ and β‐glycolide controlled by the type of organic solvents and/or temperatures, during which an intermediate crystal form of β′‐glycolide is newly observed. The transformation between α‐, β‐, and β′‐glycolide is investigated in detail, and the stabilities of different crystal forms are illustrated via the controlled experiments under different relative humidity (RH) as well as the theoretical calculations, which should provide fundamental concepts and guidance for the industrial production of glycolide and optimization of polyglycolic acid products. [ABSTRACT FROM AUTHOR]

Catalytic conversion of CO2 into high value‐added chemicals using renewable energy is an attractive strategy for the management of CO2. However, achieving both efficiency and product selectivity remains a great challenge. Herein, a brand‐new family of 1D dual‐channel heterowires, Cu NWs@MOFs are constructed by coating metal–organic frameworks (MOFs) on Cu nanowires (Cu NWs) for electro‐/photocatalytic CO2 reductions, where Cu NWs act as an electron channel to directionally transmit electrons, and the MOF cover acts as a molecule/photon channel to control the products and/or undertake photoelectric conversion. Through changing the type of MOF cover, the 1D heterowire is switched between electrocatalyst and photocatalyst for the reduction of CO2 with excellent selectivity, adjustable products, and the highest stability among the Cu‐based CO2RR catalysts, which leads to heterometallic MOF covered 1D composite, and especially the first 1D/1D‐type Mott–Schottky heterojunction. Considering the diversity of MOF materials, the ultrastable heterowires offer a highly promising and feasible solution for CO2 reduction. [ABSTRACT FROM AUTHOR]

A series of lanthanide metal‐organic frameworks (MOFs) have been assembled with a series of functionalized [1,1′:4′,1′′‐terphenyl]‐4,4′′‐dicarboxylic acid ligands. The relationship between the ligand properties and the corresponding MOF properties has been studied. The structures of the MOFs depend on the solvent‐ligand and ligand‐ligand interactions, as well as the size of the non‐coordinating functional groups of the ligands. The differences in thermal stability among the ligands are inherited and amplified by corresponding lanthanide MOFs. The ligands bearing methyl, ether, and aldehyde functional groups are capable of sensitizing the emission from the lanthanide centers, whereas the ligand with α,β‐unsaturated ketone functional groups are non‐emissive due to the mismatch of the ligand and metal energy levels. [ABSTRACT FROM AUTHOR]

The widespread use of chemicals has brought serious water pollution threatening human health and environment, which requires green, fast, and low‐cost purification urgently. Here, we build up a novel material family of sky‐parking‐like 3D structured graphene oxides (SP‐GOs) with adjustable interlayer‐space of 0.8–1.7 nm via the insertion of different sized diamine compounds as support pillars between GO layers. The assembled 3D SP‐GOs exhibit superior adsorption capacity and short removal time for various aromatic organic compounds in water, achieving record‐breaking maximum adsorption capacity of 535.79 mg g−1 toward the most common water‐pollutant bisphenol A (BPA) at ambient conditions as well as significantly improved removal of other organic pollutants including sulfapyridine, carbamazepine, ketoprofen and 2‐naphthol. The construction of SP‐GO provides a simple approach for evolving the GO material from 2D to 3D and a new avenue for the decontamination of pollutants in environmental remediation. [ABSTRACT FROM AUTHOR]

Two C2H6‐selective metal‐organic framework (MOF) adsorbents with ultrahigh stability, high surface areas, and suitable pore size have been designed and synthesized for one‐step separation of ethane/ethylene (C2H6/C2H4) under humid conditions to produce polymer‐grade pure C2H4. Experimental results reveal that these two MOFs not only adsorb a high amount of C2H6 but also display good C2H6/C2H4 selectivity verified by fixed bed column breakthrough experiments. Most importantly, the good water stability and hydrophobic pore environments make these two MOFs capable of efficiently separating C2H6/C2H4 under humid conditions, exhibiting the benchmark performance among all reported adsorbents for separation of C2H6/C2H4 under humid conditions. Moreover, the affinity sites and their static adsorption energies were successfully revealed by single crystal data and computation studies. Adsorbents described in this work can be used to address major chemical industrial challenges. [ABSTRACT FROM AUTHOR]

Environmental problem caused by carbon emission is of widespread concern. Involving CO2 as C1 resource into chemical synthesis is one of the most attractive ways for carbon recycling. Herein, the first example of host–guest composites featuring metal–organic framework (MOF)‐encapsulated binuclear N‐heterocyclic carbene (NHC) complex, Co2@MIL101, was developed with the molecularly dispersed [Co(IPr)Br]2(μ‐Br)2 (Co2) loading in the cage of MIL‐101(Cr) via a "ligand‐in‐dimer‐trap" strategy, which was comprehensively investigated through various techniques including synchrotron X‐ray absorption, electron microscopy, X‐ray diffraction, solid‐state nuclear magnetic resonance spectroscopy, and others. The noble‐metal‐free double‐sites catalyst Co2@MIL101 exhibited promising stability, activity, efficiency, reusability, and substrate adaptability for converting CO2 into various formamides with amines and hydrosilanes and achieved the best performance for one of the most useful formamides, N‐methyl‐N‐phenylformamide (MFA), among the recyclable catalysts at ambient conditions, providing a reliable approach to successfully unify the advantages of both homo‐ and heterogeneous catalysts. Density functional theory calculations were applied to illustrate the superior activity of the binuclear NHC complex center as double‐sites catalyst toward the activation of CO2. [ABSTRACT FROM AUTHOR]

In the surroundings of carbon neutrality, nano‐Cu2O is considered a promising catalyst for the electrochemical CO2 reduction reaction (ECO2RR), whose improvements in product selectivity still require considerable efforts. Here, we present an efficient strategy for controlling the ECO2RR product by modifying the surface of nano‐Cu2O, i.e. by controlling the exposed facets via a reductant‐controlled method to achieve the highest C2H4 selectivity (Faradic efficiency=74.1 %) for Cu2O‐based catalysts in neutral electrolytes, and introducing a well‐suited metal–organic framework (MOF) coating on the surface of nano‐Cu2O to obtain syngas completely with an appropriate H2:CO ratio. Detailed mechanism and key intermediate have been illustrated by DFT calculations. Our systematic strategy is expected to control the ECO2RR product, improve the selectivity, and provide a reliable method for CO2 management and the green production of important carbon resources. [ABSTRACT FROM AUTHOR]

Abstract: The integration of metal/metal oxide nanoparticles (NPs) into metal–organic frameworks (MOFs) to form composite materials has attracted great interest due to the broad range of applications. However, to date, it has not been possible to encapsulate metastable NPs with high catalytic activity into MOFs, due to their instability during the preparation process. For the first time, we have successfully developed a template protection–sacrifice (TPS) method to encapsulate metastable NPs such as Cu2O into MOFs. SiO2 was used as both a protective shell for Cu2O nanocubes and a sacrificial template for forming a yolk–shell structure. The obtained Cu2O@ZIF‐8 composite exhibits excellent cycle stability in the catalytic hydrogenation of 4‐nitrophenol with high activity. This is the first report of a Cu2O@MOF‐type composite material. The TPS method provides an efficient strategy for encapsulating unstable active metal/metal oxide NPs into MOFs or maybe other porous materials. [ABSTRACT FROM AUTHOR]

Silver nanoparticles were successfully supported on the zeolite-type metal-organic framework MIL-101 to yield Ag@MIL-101 by a simple liquid impregnation method. For the first time, the conversion of terminal alkynes into propiolic acids with CO2 was achieved by the use of the Ag@MIL-101 catalysts. Owing to the excellent catalytic activity, the reaction proceeded at atmospheric pressure and low temperature (50 °C). The Ag@MIL-101 porous material is of outstanding bifunctional character as it is capable of simultaneously capturing and converting CO2 with low energy consumption and can be recovered easily by centrifugation. [ABSTRACT FROM AUTHOR]

Catalytic conversion of CO2 into high value‐added chemicals using renewable energy is an attractive strategy for the management of CO2. However, achieving both efficiency and product selectivity remains a great challenge. Herein, a brand‐new family of 1D dual‐channel heterowires, Cu NWs@MOFs are constructed by coating metal–organic frameworks (MOFs) on Cu nanowires (Cu NWs) for electro‐/photocatalytic CO2 reductions, where Cu NWs act as an electron channel to directionally transmit electrons, and the MOF cover acts as a molecule/photon channel to control the products and/or undertake photoelectric conversion. Through changing the type of MOF cover, the 1D heterowire is switched between electrocatalyst and photocatalyst for the reduction of CO2 with excellent selectivity, adjustable products, and the highest stability among the Cu‐based CO2RR catalysts, which leads to heterometallic MOF covered 1D composite, and especially the first 1D/1D‐type Mott–Schottky heterojunction. Considering the diversity of MOF materials, the ultrastable heterowires offer a highly promising and feasible solution for CO2 reduction. [ABSTRACT FROM AUTHOR]