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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]

The electrochemical carbon dioxide reduction reaction (eCO2RR) represents an effective means of achieving renewable energy storage and a supply of carbon-based raw materials. However, there are still great challenges in selectively producing specific hydrocarbon compounds. The unique ability of the copper (Cu) catalyst to promote proton-coupled electron transfer processes offers clear advantages in generating value-added products. This review presents molecular enhancement strategies for Cu-based catalysts for CO2 electroreduction. We also elucidate the principles of each strategy for enhancing eCO2RR performance, discuss the structure–activity relationships, and propose some promising molecular enhancement strategies. This review will provide guidance for the development of organic–inorganic hybrid Cu-based catalysts as high-performance CO2 electroreduction catalysts. [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]

Green and economical synthetic approaches for metal–organic frameworks (MOFs) and incorporating multiple functionalities into MOF matrixes are of great interest for wide applications. Herein, we developed a rapid, high-throughput and universal centrifuge tube grinding (CTG) synthetic strategy for the synthesis of a series of popular MOFs in centrifuge tubes. Significantly, a variety of catalytic and optically active organic, biological and complex molecules were incorporated into the in situ formed defects of MOF skeletons by one-pot CTG synthesis to achieve various novel MOF-encapsulated composite materials. Types of MOFs as well as different composites can be rapidly and greenly synthesized simultaneously in centrifuge tubes with different sizes on a single vortex mixer even on a gram scale. Our strategy provides a facile route for the incorporation of multiple functionalities, especially large active molecules, into MOFs and for greenly affording various MOF-based materials towards various applications in diverse areas. [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]

Developing new strategies to enhance adsorbents' gas separation performance is highly desirable. In this contribution, we created a post-synthetic modification approach to enhance the C2H2/CO2 separation performance for an ultramicroporous MOF (NKMOF-2) platform that underwent a single-crystal-to-single-crystal in the counter anion exchange process. Substitution of Cl− with BF4− not only greatly improved the water stability of the NKMOF-2 platform but also enhanced their adsorption capacity and separation performance. Mixture gas breakthrough experiments revealed that the anion exchange strategy was a powerful approach for boosting the selective adsorption of C2H2 over CO2. Moreover, we first observed that the C2H2/CO2 separation performance could be enhanced dramatically by elevating the test temperature. This study not only enriches the toolbox to create efficient MOF adsorbents for gas separation but also provides a fundamental understanding of the enhanced gas uptake and separation performance. [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]