Conductive Metal–Organic Frameworks: Design, Synthesis, and Applications

Abstract

fabricated. Combined with controlled synthesis, MOF materials are endowed with abundant various of structures, morphologies, and properties. [8-11] In addition, the as-prepared MOFs can be artificially modified via postsynthetic approaches utilizing their available pores and active sites of metal clusters or linkers. [12,13] As a result, not only the number of MOFs is further increased but also many interesting properties, such as high specific surface areas, tailorable pore sizes, modifiable structures, and properties are endowed with MOFs, which make them become potential candidates in storage/separation, catalysis, sensing, etc. [14,15] Another important application of MOFs is that they can act as conductive materials for electrocatalysis, sensing, and energy conversion, etc. [16-19] The existence of quantitative amounts of active metal centers, permanent porosity, and structural rigidity can facilitate surface contact and mass transfer as well as increase catalysis stability, making MOFs as ideal electrocatalysts. [20-22] In addition, they possess high specific surface areas, tunable bandgaps, and good charge transport properties, which extend their applications in sensing and energy storage. [23] Besides, the morphologies and characteristics of MOFs can be artificially modified to form 1D, 2D, or 3D structures via liquid phase selfassembly, physical/chemical exfoliation, layer-by-layer assembly, etc., promoting their applications in electrochemical devices and electronics. [24-26] With further structural design through postsynthesized modification, the performances of MOFs can be largely improved, facilitating their applications as conductive materials. [27-29] However, most MOFs are intrinsically electrically insulated, which seriously hinders their electrochemical applications. [29] The connected rigid metal ions and redox-inactive organic ligands increase the energy barrier for electron transfer, making them as electrical insulators. To overcome the drawbacks of MOFs, many feasible strategies have been adopted to promote the electron transfer in the structures of MOFs. [27,30-32] The high electrical conductivity of MOFs can be realized by integrating the conjugated planes or 1D chains in the structures, which relies on particular structural designs. [33-37] The conductivity of the MOFs can also be increased via doping with guest Metal-organic frameworks (MOFs) have aroused worldwide interest over the last two decades due to their various excellent properties, such as porosity, modifiability, stability, etc. Based on these unique features, they have been widely exploited for applications from electrocatalysis to electrochemical devices. However, most MOFs are inherently insulated due to the lack of free charge carriers and low-energy barriers for charge transfer, which largely restricts their further electrochemical applications. By imparting MOFs with electrical conductivity, their electrochemical process and catalysis efficiency can be effectively improved. Similarly, their applications in sensors, secon...

Constructing Well-Defined and Robust Th-MOF-Supported Single-Site Copper for Production and Storage of Ammonia from Electroreduction of Nitrate

“… 40 − 43 Moreover, incorporating single-site Cu on BPYDC also can result in the energetic overlap between Th 6 nodes and the ligand, thus promoting the charge transport by the “through-bond” route. 44 The electrochemical impedance spectroscopy (EIS) measurements were also carried out. As revealed by Nyquist curves in Figure S6 , incorporating single-site Cu into Th-BPYDC can significantly decrease the interfacial charge transfer resistance between catalysts and electrolyte, 45 which implies the enhanced conductivity of Cu@Th-BPYDC, well consistent with the results of electrical conductivity in Th-BPYDC and Cu@Th-BPYDC.…”

Recent Progress in Designing Thermoelectric Metal–Organic Frameworks

“…Fortunately, with the high tunability in molecular structures, many feasible approaches have been developed in recent years to manipulate their electronic structure, thus overcoming their major drawback and facilitating efficient electron transfer. [37][38][39] Moreover, various arrangement combinations of inorganic or organic units potentially give rise to new physical phenomena, [40,41] and versatile regulation strategies of S, σ, and κ can thus be anticipated in pursuing higher ZT values.…”

“…So far, there have been several review articles specifically focused on the improvement of electrical conductivity for MOFs targeted at applications of electrochemical sensing, photovoltaic devices, electrocatalysis, and energy storage. [37,38,42] Whereas, the requirement of improving electrical conductivity for thermoelectrics is notably different from it for other applications. However, the improvement of electrical conductivity for MOFs targeted at applications of thermoelectrics is still a great challenge because, for example, promoting charge transfer via increasing charge carrier density would lead to the decrease of the Seebeck coefficient as the two parameters are interdependent and subjected to certain laws of physics.…”

Enhancing One‐Dimensional Charge Transport in Metal‐organic Framework Hexagonal Nanorods for Electrocatalytic Oxygen Evolution

“…The R ct values for Ni‐HXR and NiFe‐HXR are lower than those for traditional MOFs (Figure 2e), indicating that integrating “through‐bond” and “through‐space” strategy into one MOF can enhance charge carrier efficiency. Moreover, the bimetallic NiFe‐HXR exhibits significantly superior charge transfer dynamics with regard to monometallic Ni‐HXR and commercial IrO 2 benchmark, which is ascribed to the enhanced charge transport through node to node induced by strong interaction between Ni and Fe nodes [21] . To further investigate the origin of the excellent performance in NiFe‐HXR, the electrochemical surface areas (ECSA) that is proportional to the double layer capacitances ( C dl ) was determined by CV method (Figure S7).…”