Sequencing of metals in multivariate metal-organic frameworks

Ji, Zhe; Li, Tong; Yaghi, Omar M.

doi:10.1126/science.aaz4304

Cited by 203 publications

(146 citation statements)

References 47 publications

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“…A very recent work delivered by Yaghi's group has shed light on this issue. [ 274 ] Briefly, atom probe tomography technique—in which sample are sequentially evaporated from the surface by laser pulsing and identified by time‐of‐flight mass spectrometry—has been used for unveiling metal sequences in bimetallic MTV‐MOFs at molecular level. By adjusting the mixing enthalpy (lattice matching of two metals) and configurational entropy (the number of ways for metal arrangement) via controlling the kinds of metals as well as the reaction temperature, diverse metal sequences including random distribution, short/long duplicates, and insertions have been observed.…”

Section: Discussionmentioning

confidence: 99%

Porosity Engineering of MOF‐Based Materials for Electrochemical Energy Storage

Yang

et al. 2021

Advanced Energy Materials

106

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energy storage (EES)-primarily supercapacitors and metal-ion batteries (MIBs, e.g., lithium-ion batteries (LIBs), sodiumion batteries (SIBs), and potassium-ion batteries (PIBs)).Both supercapacitors and batteries typically consist of current collectors, electrodes, electrolyte, and a separator. By applying a suitable potential between current collectors, the charge/discharge process takes place mediated by the electrode materials, and the electrolyte ions (i.e., the charge carriers) are accordingly driven to travel across the separator so as to connect the circuit. In recent years, solidstate electrolytes (SSEs) are also under popular development to enhance cell voltage (energy density) and safety of the devices. [1] Upon charging, electrical energy is converted to electrostatic potential for supercapacitors and to chemical energy for batteries, and vice versa. Therefore, each device has pros and cons. Supercapacitors usually provide a high power density (i.e., a fast charge/ discharge velocity) due to the fast physical charge-discharge process across the interfaces between electrode materials and the electrolyte solutions, while the energy density is usually small (≈5 Wh kg −1 ). In comparison, batteries often offer a large energy density (i.e., a large specific energy capacity of ≈200 Wh kg −1 ) attributed to the chemical redox reactions which take place throughout the whole volume of electrode materials, while the operation rate is relatively slow. [2] To construct desirable energy storage devices, porous materials have been widely adopted, particularly for electrodes and SSEs. These materials typically feature a large fraction of interconnected or reticulated porosity with a high specific surface area (SSA), offering numerous potential active sites and mass transfer channels. For example, porous materials based on nanocarbons (e.g., carbon nanotubes, graphene), conducting polymers, and conjugated microporous polymers with high electrical conductivity and large SSAs have been frequently adopted for supercapacitors, [3] while porous carbons, MoS 2 , and metal oxides have been used for LIBs because of the theoretically large stoichiometric lithium content in the respectively lithiated compound and an accelerated Li diffusion rate inside the pores. [4][5][6] Despite considerable progress made so far, these porous materials fall short of sufficiently large SSAs and readily tunable pores, which constrain the upper limit for the performance optimization and affect an accurate investigation of the structure-performance relationship.Metal-organic frameworks (MOFs) feature rich chemistry, ordered micro-/ mesoporous structure and uniformly distributed active sites, offering great scope for electrochemical energy storage (EES) applications. Given the particular importance of porosity for charge transport and catalysis, a critical assessment of its design, formation, and engineering is needed for the development and optimization of EES devices. Such efforts can be realized via the design of reticular chemistry, multiscale...

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Section: Discussionmentioning

confidence: 99%

Porosity Engineering of MOF‐Based Materials for Electrochemical Energy Storage

Yang

et al. 2021

Advanced Energy Materials

106

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“…( C ) Schematic showing the use of atom probe tomography to map the metal sequence in the multivariate MOF samples. Reproduced with permission from the American Association for the Advancement of Science ( 140 ). ( D ) High-resolution TEM image of the junction in an Au─Co─PdSn nanoparticle (scale bar, 3 nm), where the insets show the ADF-STEM image and corresponding EDS element map of the entire nanoparticle.…”

Section: Moving Forward: Opportunities and Challengesmentioning

confidence: 99%

High-entropy materials for catalysis: A new frontier

2021

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Entropy plays a pivotal role in catalysis, and extensive research efforts have been directed to understanding the enthalpy-entropy relationship that defines the reaction pathways of molecular species. On the other side, surface of the catalysts, entropic effects have been rarely investigated because of the difficulty in deciphering the increased complexities in multicomponent systems. Recent advances in high-entropy materials (HEMs) have triggered broad interests in exploring entropy-stabilized systems for catalysis, where the enhanced configurational entropy affords a virtually unlimited scope for tailoring the structures and properties of HEMs. In this review, we summarize recent progress in the discovery and design of HEMs for catalysis. The correlation between compositional and structural engineering and optimization of the catalytic behaviors is highlighted for high-entropy alloys, oxides, and beyond. Tuning composition and configuration of HEMs introduces untapped opportunities for accessing better catalysts and resolving issues that are considered challenging in conventional, simple systems.

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“…3(c)], demonstrating that both random and correlated sequence types emerge naturally from different metal combinations and different synthesis temperatures. 62 While both REDOR-NMR and APT provide very detailed information, they are nonetheless demanding techniques. By contrast, we have found that humble infrared spectroscopy can offer a surprisingly straightforward measure of cation distributions in mixed-metal MOFs and coordination polymers [ Fig.…”

Section: Compositional Disordermentioning

confidence: 99%