Even as the evidence of global warming mounts, the international response to this serious threat is coming unraveled. The United States has formally withdrawn from the 1997 Kyoto Protocol; other key ...nations are facing difficulty in meeting their Kyoto commitments; and developing countries face no limit on their emissions of the gases that cause global warming. In this clear and cogent book-reissued in paperback with an afterword that comments on recent events--David Victor explains why the Kyoto Protocol was never likely to become an effective legal instrument. He explores how its collapse offers opportunities to establish a more realistic alternative.
Metal‐organic frameworks (MOFs) hold great promise as high‐energy anode materials for next‐generation lithium‐ion batteries (LIBs) due to their tunable chemistry, pore structure and abundant reaction ...sites. However, the pore structure of crystalline MOFs tends to collapse during lithium‐ion insertion and extraction, and hence, their electrochemical performances are rather limited. As a critical breakthrough, a MOF glass anode for LIBs has been developed in the present work. In detail, it is fabricated by melt‐quenching Cobalt‐ZIF‐62 (Co(Im)1.75(bIm)0.25) to glass, and then by combining glass with carbon black and binder. The derived anode exhibits high lithium storage capacity (306 mAh g−1 after 1000 cycles at of 2 A g−1), outstanding cycling stability, and superior rate performance compared with the crystalline Cobalt‐ZIF‐62 and the amorphous one prepared by high‐energy ball‐milling. Importantly, it is found that the Li‐ion storage capacity of the MOF glass anode continuously rises with charge–discharge cycling and even tripled after 1000 cycles. Combined spectroscopic and structural analyses, along with density functional theory calculations, reveal the origin of the cycling‐induced enhancement of the performances of the MOF glass anode, that is, the increased distortion and local breakage of the CoN coordination bonds making the Li‐ion intercalation sites more accessible.
A ZIF glass (melt‐quench Co ZIF‐62 glass), for the first time, is evaluated as anode for high performance lithium‐ion batteries. This ZIF glass anode exhibits an unusual capacity enhancement during charge‐discharge cycling. This exceptional phenomenon is related to the unique structure of ZIF glass, e.g., short‐range disorder.
We herein report a rigid nested metal–organic framework (MOF) featuring a unique thermoresponsive gating adsorption behavior, which, in contrast to any known flexibility modes for stimuli‐responsive ...MOFs, depends on the thermal motion of the extra‐framework counterions. In addition, this MOF also exhibits adsorption selectivity of CO2 over N2, H2, and Ar at 273 K, thus enabling a strategic separation and encapsulation of CO2.
A thermal cork screw: Counterions act as removable corks blocking the pore openings of a rigid nested metal–organic framework (MOF). The thermoresponsive gating adsorption behavior of the MOF is dominated by the counterion corks, rather than the flexibility modes of other stimuli‐responsive MOFs. On heating, the corks are removed from the openings, on cooling they return.
The sensing performances of gas sensors must be improved and diversified to enhance quality of life by ensuring health, safety, and convenience. Metal-organic frameworks (MOFs), which exhibit an ...extremely high surface area, abundant porosity, and unique surface chemistry, provide a promising framework for facilitating gas-sensor innovations. Enhanced understanding of conduction mechanisms of MOFs has facilitated their use as gas-sensing materials, and various types of MOFs have been developed by examining the compositional and morphological dependences and implementing catalyst incorporation and light activation. Owing to their inherent separation and absorption properties and catalytic activity, MOFs are applied as molecular sieves, absorptive filtering layers, and heterogeneous catalysts. In addition, oxide- or carbon-based sensing materials with complex structures or catalytic composites can be derived by the appropriate post-treatment of MOFs. This review discusses the effective techniques to design optimal MOFs, in terms of computational screening and synthesis methods. Moreover, the mechanisms through which the distinctive functionalities of MOFs as sensing materials, heterostructures, and derivatives can be incorporated in gas-sensor applications are presented.
Photoreduction of CO2 into reusable carbon forms is considered as a promising approach to address the crisis of energy from fossil fuels and reduce excessive CO2 emission. Recently, metal–organic ...frameworks (MOFs) have attracted much attention as CO2 photoreduction‐related catalysts, owing to their unique electronic band structures, excellent CO2 adsorption capacities, and tailorable light‐absorption abilities. Recent advances on the design, synthesis, and CO2 reduction applications of MOF‐based photocatalysts are discussed here, beginning with the introduction of the characteristics of high‐efficiency photocatalysts and structural advantages of MOFs. The roles of MOFs in CO2 photoreduction systems as photocatalysts, photocatalytic hosts, and cocatalysts are analyzed. Detailed discussions focus on two constituents of pure MOFs (metal clusters such as Ti–O, Zr–O, and Fe–O clusters and functional organic linkers such as amino‐modified, photosensitizer‐functionalized, and electron‐rich conjugated linkers) and three types of MOF‐based composites (metal–MOF, semiconductor–MOF, and photosensitizer–MOF composites). The constituents, CO2 adsorption capacities, absorption edges, and photocatalytic activities of these photocatalysts are highlighted to provide fundamental guidance to rational design of efficient MOF‐based photocatalyst materials for CO2 reduction. A perspective of future research directions, critical challenges to be met, and potential solutions in this research field concludes the discussion.
Photocatalyst materials based on metal–organic frameworks (MOFs) have great potential for carbon dioxide (CO2) reduction due to their tailorable light‐absorption ability, unique pore texture, and excellent CO2 adsorption capacity. A comprehensive review of recent advances in the design, synthesis, and CO2 photoreduction applications of MOF‐based photocatalysts is presented to offer valuable insights toward the exploitation of new‐generation photocatalyst materials.
Abstract Nanoscale metal organic frameworks (NMOFs) have shown great potential in biomedicine owing to their structural/chemical diversities, high molecular loading capacities, and intrinsic ...biodegradability. Herein, we report the rational design of a NMOF composed by hafnium (Hf4+ ) and tetrakis (4-carboxyphenyl) porphyrin (TCPP). In such Hf-TCPP NMOFs, while TCPP is a photosensitizer to allow photodynamic therapy (PDT), Hf4+ with strong X-ray attenuation ability could serve as a radio-sensitizer to enhance radiotherapy (RT). Those NMOFs with polyethylene glycol (PEG) coating show efficient tumor homing upon intravenous injection, and thus could be used for in vivo combined RT & PDT, achieving a remarkable anti-tumor effect. Importantly, Hf-TCPP NMOFs show efficient clearance from the mouse body, minimizing concerns regarding their possible long-term toxicity. Our work thus presents a new concept of developing multifunctional NMOFs as a biodegradable carrier-free system, in which both metal ions and organic ligands are fully utilized to exert their therapeutic functions.
Metal organic frameworks (MOFs) are a class of porous materials with a modular structure. This allows for very wide structural diversity and the possibility of synthesizing materials with tailored ...properties for advanced applications. Thus, MOF materials are the subject of intense research, with strong relevance to both science and technology. MOFs are formed by the assembly of two components: cluster or metal ion nodes, which are also called secondary building units (SBUs), and organic linkers between the SBUs, usually giving rise to crystalline structures with an open framework and significant porous texture development. The main aim of this Special Issue of Catalysts (ISSN 2073-4344) is to present the most relevant and recent insights in the field of the synthesis and characterization of MOFs and MOF-based materials for advanced applications, including adsorption, gas storage/capture, drug delivery, catalysis, photocatalysis, and/or chemical sensing.
Porphyrin‐Based Metal–Organic Frameworks
A major challenge in studying Zr‐porphyrin‐based metal–organic frameworks (MOFs) is the poor reproducibility of reported syntheses. Article number 2210613 by ...Bettina V. Lotsch and co‐workers investigates the formation of Zr‐MOF particles step‐by‐step to understand and ultimately control the critical stages during nucleation and growth. Notably, water is essential to the formation of Zr‐oxo clusters and influences both the formation kinetics and phase purity of the product.
Seawater electrolysis is a sustainable technology for producing hydrogen that would neither cause global freshwater shortages nor create carbon emissions. However, this technology is severely ...hampered by the insufficient stability and the competition from the chlorine evolution reaction (ClER) in actual application. Herein, a metal–organic framework (MOF)‐on‐MOF heterojunction (Ni‐BDC/NH2‐MIL‐88B(Fe)) denoted as (Ni‐BDC/NM88B(Fe)) is synthesized as an effective oxygen evolution reaction (OER) electrocatalyst for high‐performance seawater electrolysis, which exhibits a long stability of 200 h and low overpotentials of 232 and 299 mV at 100 mA cm−2 in alkaline freshwater and seawater solution, respectively. The exceptional performance is attributed to the rapid self‐reconstruction of Ni‐BDC/NM88B(Fe) to produce NiFeOOH protective layer, thereby avoiding ClER‐induced dissolution. Moreover, the interface interaction between Ni‐BDC and NM88B(Fe) could form the Ni─O─Fe bonds in Ni‐BDC/NM88B(Fe) to promote the electron transfer and lower the energy barrier of the rate‐determining step, thereby accelerating the OER. These electrochemical properties make it intriguing candidate as an efficient electrocatalyst for practical alkaline seawater electrolysis.
A hetero‐structured Ni‐BDC/NM88B(Fe) metal–organic framework is synthesized to be as an outstanding electrocatalyst for seawater oxidation. The unique electronic channel (Ni─O─Fe) in this heterostructure not only enables the rapid reconstruction to generate the protective layer of NiFeOOH, thereby avoiding the effects of CER, but also optimizes the adsorption energy of the intermediates, leading to superior seawater oxidation performance.
