Metal-organic Framework Derivatives Research Articles

The modification of biomass waste by cerium-based MOFs for efficient phosphate removal: excellent performance and reaction mechanism.

Due to the possibility of causing eutrophication, excessive phosphate discharged into water bodies always threatens the stabilization of aquatic ecosystem. A promising strategy is to remove phosphate from water by the utilization of biomass waste as adsorbents. In this paper, the corn straw (CS) and pine sawdust (PS) are chosen for adsorption; however, the phosphate removal capacities of them are very limited. Considering the high phosphate uptake of trivalent cerium, Ce (III)-based nanoparticles (CD and CT) are selected to be loaded on the biomass by hydrothermal synthesis to obtain four modified materials. CD is metal organic frameworks (MOFs) with Ce5(BDC)7.5(DMF)4 as its molecular structure, while CT is MOFs derivatives with [Ce (HCOO)]n as its crystal structure. The adsorption capacities of CS-CD, PS-CD, CS-CT and PS-CT reach 181.38, 183.27, 225.55 and 186.23 mg/g. But on account of the different molecular structures, CS-CD and PS-CD achieve great phosphate uptake under wide applicable scope of pH from 2 to 11, whereas CS-CT and PS-CT only under acidic conditions. The analysis of the adsorption mechanism indicates that due to the unsaturated coordination bond of CD, it could remove phosphate through coprecipitation and ion exchange even under alkaline conditions.

2D metal–organic frameworks and their derivatives for the oxygen evolution reaction

Electrocatalytic oxygen evolution reaction (OER) is a critical half reaction for energy conversion and storage technologies such as water electrolysis, rechargeable metal–air batteries, carbon dioxide reduction reaction, and so on. Unfortunately, large overpotential is needed to overcome the sluggish kinetics of OER. With ultra-thin thickness, large specific surface area, rich and adjustable pore structure, and well-defined metal centers, two dimensional (2D) metal-organic frameworks (MOFs) have been widely investigated for OER. By virtue of the desirable chemical composition and diverse structural type, 2D MOFs are also employed as precursors and sacrificial templates to prepare metal-decorated porous carbon, metal oxides, metal hydroxides, metal sulfides, metal phosphides, and so on. These 2D MOFs derivatives with high surface area and abundant metal sites exhibit excellent OER performance. Herein, the current advances on 2D MOFs and their derivatives as (pre)electrocatalysts are summarized, including the synthetic strategy and OER performance. Moreover, the structure-performance relationships and actual active species or sites of 2D MOFs and their derivatives toward OER are discussed. The current scientific and technological challenges and future perspectives related with 2D MOF and their derivatives in practical applications are also mentioned at last.

Fe-metal-organic-framework/MnO2 nanowire/granular activated carbon nanostructured composites for enhanced As(III) removal from aqueous solutions

The elimination of arsenic pollution has attracted increasing concerns due to its toxicity and severe carcinogenicity. Herein, we proposed an in-situ crystal growth strategy without surfactant to fabricate MIL-88B uniformly anchored on the surface of MnO2/GAC (MIL-88B/MnO2/GAC). Such innovative MIL-88B/MnO2/GAC nanostructured composites not only exhibited the synergetic functions of simultaneously oxidizing As(III) and adsorbing the generated As(V), but also effectively reduced the cost of metal–organic frameworks (MOFs) adsorbents. Impressively, the as-prepared sample achieved remarkably boosted As(III) removal capacity of 15.13 mg g−1 compared to 4.1 mg g−1 of MnO2/GAC composite and 2.1 mg g−1 of GAC, which was mainly ascribed to the synergistic effect between the excellent adsorption abilitiy of MIL-88B and oxidation property of MnO2/GAC. Owing to the unique construction and properties, the constructed MIL-88B/MnO2/GAC composites presented a desirable As(III) removal ability under a wide pH scope of 2 to 10. Moreover, the possible mechanism of the synergistic removal over MIL-88B/MnO2/GAC was elucidated by X-ray photoelectron spectroscopy (XPS), electron spin resonance (ESR) and radical trapping experiment. This work not only offers a superior bifunctional catalyst for high-efficient removal of arsenic, but also provides a new perspective for rational construction of MOF derivatives for their further applications.

Semiconducting metal-organic framework derivatives-gated organic photoelectrochemical transistor immunoassay

Metal-organic framework (MOF) derivatives with unique physicochemical and electronic properties have seen a tremendous growth in diverse applications. Organic optobioelectronics have long been pursued in modern electronics for next-generation bio-relevant implementations. The intersection of these two disciplines could be an appealing way to pursue better performance of materials and devices. Herein this work reports the exploration of MOF derivatives and its ionic modulation for gating organic photoelectrochemical transistor (OPECT) biosensing. In the representative system of poly(ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) gated by zeolitic-imidazolate-framework (ZIF)-8-derived CdxZn1-xS, a high current gain could be achieved at zero gate bias. In connection to a CuO nanoparticle-labeled sandwich immunoassay, acidolysis-triggered Cu2+-induced ionic modulation of the system results into a good performance toward human IgG with a low limit of detection of 0.003 pg/mL. This work features the MOF derivative-gated organic electronics and is expected to inspire more interest to explore various MOF derivative electronics with unknown possibilities, considering the diversity of MOF derivatives.

Design of novel cobalt-based perovskite derivatives using sulfurization as active material of energy storage devices

Metal organic framework (MOF) derivatives have attracted much attention as efficient active material of energy storage device, due to large surface area, excellent pore structure and abundant redox states. Previously ammonia fluoride is used to control morphology of zeolitic imidazolate framework 67 (ZIF-67) and supply NH4+ and F− to enhance charge transfer. More treatments are worthy to apply for improving energy storage ability of this ZIF-67 derivative. In this study, sulfurized ammonium-decorated cobalt fluoride (S-NH4-CoF) is firstly synthesized using ZIF-67 derivative and sulfur powder in the one-step annealing process at different temperatures as active material. The optimized S-NH4-CoF electrode prepared at 400 °C shows specific capacitance (CF) of 462.1 F g−1 at 20 mV s−1, due to round particle-assembled sphere morphology with high surface area and large pore volume, and suitable ratio of cobalt fluoride and cobalt sulfide. The symmetric energy storage device composed of optimized S-NH4-CoF electrodes shows maximum energy density of 30.47 Wh kg−1 at 800 W kg−1. The CF retention of 85% and Coulombic efficiency higher than 97% are obtained after 20,000 charge/discharge times. This study supplies important information about sulfurization on MOF derivatives. Other parameters like sulfurization precursor and duration are worthy to discuss for enhancing energy storage ability of S-NH4-CoF.

Binder-free synthesis of metal organic framework derived cobalt sulfide on carbon cloth for efficient energy storage devices

Cobalt based metal organic framework (Co-MOF) derivatives are regarded as attractive electroactive materials for energy storage, due to its high surface area, excellent pore structure and the possible formation of cobalt compounds. Cobalt sulfide with multiple redox states of Co and high electronegativity of S can produce numerous redox reactions for electron storage and provide high electrical conductivity for charge transfer. In this work, it is the first time to synthesize the novel binder-free sulfurized Co-MOF electrode as energy storage electrode of supercapacitor (SC). Three sulfur sources are used to sulfurize the Co-MOF electrode in hydrothermal process. The sulfurized Co-MOF prepared using thiourea (S67/CC-thiourea) shows wrinkles surface and particle connected aggregations, which can provide high surface area and electrical conductivity, respectively. The highest specific capacitance (CF) of 469.5 F/g at 4 A/g is achieved for the S67/CC-thiourea electrode. The untreated Co-MOF electrode merely shows a CF value of 8.0 F/g. An asymmetric SC is assembled using activated carbon negative electrode and S67/CC-thiourea positive electrode. A maximum energy density of 3.25 Wh/kg at 275 W/kg, and CF retention of 106 % and Coulombic efficiency higher than 91 % after 10,000 charge/discharges cycles are obtained for the asymmetric SC. This work opens new routes for creating novel MOF derivatives directly on conductive substrate using simple experimental processes.

Zn-Metal-Organic Framework Derived Ordered Mesoporous Carbon-Based Nanostructure for High-Performance and Universal Multivalent Metal Ion Storage.

Metal-organic framework (MOF) derivatives promise great potential in energy storage and conversion because of their excellent tunability in both the active metal sites, organic links, and the overall structures down to atomic and up to mesoscale. Nevertheless, a big challenge is to precisely control and thoroughly understand the actual MOF-to-derivative conversion process to realize the template-free synthesis of the MOF-derived ordered mesoporous materials. Here, a class of ordered mesoporous N-doped carbon nanoflakes is presented with slit-shaped pores synthesized by one-step pyrolysis of Zn1 Cux -MOF, where the Cu doping plays a critically important direction-inducing function on the dissociation of organic ligands during the pyrolysis. Benefiting from the uniquely ordered mesoporous structure and large specific surface area (910 m2 g-1 ), the Zn1 Cux -MOF-derived ordered mesoporous carbon nanoflakes present outstanding electrochemical storage performance for multivalent metal ions, such as Mg2+ , Ca2+ , Co2+ , Ni2+ , Al3+ , and Zn2+ , demonstrating the universal nature of the slit-shaped pores in enabling the multivalent metal ions for energy storage. Moreover, the assembled flexible Zn-ion hybrid supercapacitor (ZHSC) delivers a high specific capacity of 134 mAh g-1 at 0.5 A g-1 , excellent cycling and mechanical stability, showing great application potential in the new generation energy storage devices.

Nickel metal-organic framework microspheres loaded with nickel-cobalt sulfides for supercapacitor electrode materials

Metal-organic frameworks (MOFs) are commonly used for template and precursor for supercapacitor electrodes. MOFs are interesting due to excellent specific surface areas and pore structures. Two-dimensional nanosheets suffer from the disadvantages of random growth and easy agglomeration, which significantly limit their applications. In this study, NiCo sulfides with unique morphology were designed using a simple in situ sulfidation method, with Ni-MOF used as the substrate material. The unique three-dimensional structures can offer many reaction sites to guarantee electron transfer. The samples obtained (Ni7S6@NiCo2S4) exhibited good electrochemical performance. The composite electrode material had a capacity value of 1636 F g−1 in a 3 M KOH. In addition, devices comprising with activated carbon had a specific energy of 53 Wh kg−1 and a specific power of 810 W kg−1. The asymmetric supercapacitor (ASC) exhibited outstanding cycling of 87 % after 5000 cycles. This study demonstrates a flexible method for activating MOFs to enhance the capabilities of supercapacitor materials. Thus, this method maintains a well-defined stacking structure of nanosheets while enriching the active sites, it is promising for the applications of MOF derivatives.

Tunable regulation of metal-semiconductor heterostructures toward Ag/ZnO hybrids for electromagnetic wave absorption

Metal-organic frameworks (MOFs) with tunable nano-micro structures ikhas been widely employed on developing electromagnetic wave (EMW) absorption materials (MAMs). However, the electromagnetic (EM) response and EMW absorption mechanism of heterogeneous metallic MOFs derivatives have not been systematically studied. In this work, a series of Ag/ZnO@C hybrid materials with metal-semiconductor heterostructures were prepared by using ZIF-L with adjustable cation exchange. As Zn2+ is replaced by Ag+, the structure of ZIF-L changes gradually, which determined the crystal and structure of Ag/ZnO@C hybrid materials. Finally, the minimum reflection loss (RLmin) of the product obtained at 60 ℃ reached − 37.13 dB at 3.0 mm, and the maximum absorption bandwidth (fE) reached 6.8 GHz at 4.0 mm (loading content = 33 wt%). Therefore, this work can provide guidance for the design of hybrid structural MAMs by phase transformation MOFs.

Porous CoNiOOH nanosheets derived from the well-mixed MOFs as stable and highly efficient electrocatalysts for water oxidation

The development of efficient and stable electrocatalysts is of great significance for improving water splitting. Among them, transition metal oxyhydroxides show excellent performance in oxygen evolution reactions (OER), but there are certain difficulties in direct preparation. Recently, Metal–organic frameworks (MOFs) as precatalysts or precursors have shown promising catalytic performance in OER and can be decomposed under alkaline conditions. Therefore, using a mild and controllable way to convert MOFs into oxyhydroxides and retaining the original structural advantages is crucial for improving the catalytic activity. Herein, a rapid electrochemical strategy is used to activate well-mixed MOFs to prepare Co/Ni oxyhydroxide nanosheets for efficient OER catalysts, and the structural transformation in this process was investigated in detail by using scanning electron microscope, X-ray diffraction, Raman, X-ray photoelectron spectroscopy and electrochemical methods. It is discovered that electrochemical activation can promote ligand substitution of well-mixed MOFs to form porous oxyhydroxide nanosheets and tune the electronic structure of the metal (Co and Ni), which can lead to more active site exposure and accelerate charge transfer. In addition, the change of structure also improves hydrophilicity, as well as benefiting from the strong synergistic effect between multiple species, the optimal a-MCoNi–MOF/NF has excellent OER performance and long-term stability. More obviously, the porous CoNiOOH nanosheets are formed in situ during electrochemical activation process through structural transformation and acts as the active centers. This work provides new insights for mild synthesis of MOFs derivatives and also provides ideas for the preparation of highly efficient catalysts.

Novel magnetic metal-organic framework derivative: An adsorbent for efficient removal of fluorine-containing wastewater in mines

The long-term drinking of high-concentration fluorine-containing wastewater by residents in the mining area will cause fluorosis of varying severities. In order to avoid fluorosis, this paper used Fe3O4 as the core and MOF-Co as the shell to synthesize Fe3O4@MOF-Co through the layer-by-layer assembly method, and then employed cellulose nano-fibers to modify its surface. Finally, the magnetic metal-organic framework derivative (Fe3O4@MOF-Co@CNF) with core-shell structure was obtained. The adsorbent was characterized by Fourier transform infrared spectrometer (FTIR), diffraction of x-rays (XRD), scanning electron microscopy (SEM), nitrogen adsorption and desorption (BET), and thermogravimetry (TG). The effects of pH, adsorption time, temperature, initial concentration, adsorbent dosage, coexisting ions and regeneration conditions on the adsorption properties were investigated. At the same time, in order to explain the adsorption mechanism of the adsorbent, the changes of FTIR, SEM and XPS microscopic characterization before and after the adsorption were compared and analyzed. In addition, the molecular dynamic simulation technology was employed to calculate the adsorption energy and simulate the distributions of electrostatic potential and concentration for the purpose of further clarifying the adsorption mechanism. The results suggest that the interaction of ligand exchange and hydrogen bond adsorption is the key factor to promote the adsorption for F-. This paper provides a new idea for the application of adsorbent materials in wastewater treatment.

Hierarchical Bi2S3@CoS2/MoS2 core-shelled microspheres as bifunctional electrode catalysts for efficient triiodide reduction and alkaline hydrogen evolution reactions

The core-shelled structural electrocatalysts composed of multiple transition metal sulfides are of broad promise in diverse power conversion and storage techniques. Herein, we have employed a plausible strategy to synthesize a series of porous composite electrocatalytic materials with hierarchical architecture based on metal-organic framework (MOF) derivatives (Bi2S3 @CoS2/MoS2, CoS2/MoS2, and Bi2S3 @MoS2). Remarkably, by virtue of the huge specific surface area, unique surface appearance, and the synergistic effect of multi-metals, the catalyst exhibits excellent electrocatalytic performance as a bifunctional catalyst in dye-sensitized solar cells (DSSCs) and hydrogen evolution reactions (HERs). Herein, the quaternary Bi2S3 @CoS2/MoS2 microspheres exhibit remarkable merits in facilitating the regeneration of iodine redox pairs in DSSCs as well as improving hydrogen evolution activity concerning CoS2/MoS2 and Bi2S3 @MoS2 microspheres. Particularly, the DSSCs with Bi2S3 @CoS2/MoS2-based counter electrode performed superior power conversion efficiency (PCE) of 9.43 %, outperforming that of Pt (7.87 %). Besides, a low onset overpotential of 29.5 mV, small Tafel slope of 56.2 mV dec–1, and low overpotential of 94.7 mV at the current density of 10 mA cm–2 were delivered for Bi2S3 @CoS2/MoS2 as HERs electrocatalyst under alkaline environment.

Hierarchical Nanocages Assembled by NiCo-Layered Double Hydroxide Nanosheets for a High-Performance Hybrid Supercapacitor.

Layered double hydroxides (LDHs) have attracted broad attention as cathode materials for hybrid supercapacitors (HSCs) because of their ultrahigh theoretical specific capacitance, high compositional flexibility, and adjustable interlayer spacing. However, as reported, specific capacitance of LDHs is still far below the theoretical value, inspiring countless efforts to these ongoing challenges. Herein, a hierarchical nanocage structure assembled by NiCo-LDH nanosheet arrays was rationally designed and fabricated via a facile solvothermal method assisted by the ZIF-67 template. The transformation from the ZIF-67 template to this hollow structure is achieved by a synergistic effect involving the Kirkendall effect and the Ostwald ripening process. The enlarged specific surface area co-occurred with broadened interlayer spacing of LDH nanosheets by finely increasing the Ni concentration, leading to synchronous improvement of electron/ion transfer kinetics. The optimized NiCo-LDH-210 electrode displays a maximum specific capacitance of 2203.6 F g-1 at 2 A g-1, excellent rate capability, and satisfactory cycling stability because of the highly exposed active sites and shortened ion transport paths provided by vertically aligned LDH nanosheets together with the cavity. Furthermore, the assembled HSC device achieves a superior energy density of 57.3 Wh kg-1 with prominent cycling stability. Impressively, the design concept of complex construction derived from metal-organic frameworks (MOF) derivatives shows tremendous potential for use in energy storage systems.

Metal-Organic Frameworks for Electrocatalytic Sensing of Hydrogen Peroxide.

The electrochemical detection of hydrogen peroxide (H2O2) has become more and more important in industrial production, daily life, biological process, green energy chemistry, and other fields (especially for the detection of low concentration of H2O2). Metal organic frameworks (MOFs) are promising candidates to replace the established H2O2 sensors based on precious metals or enzymes. This review summarizes recent advances in MOF-based H2O2 electrochemical sensors, including conductive MOFs, MOFs with chemical modifications, MOFs-composites, and MOF derivatives. Finally, the challenges and prospects for the optimization and design of H2O2 electrochemical sensors with ultra-low detection limit and long-life are presented.

Microwave pyrolysis-engineered MOFs derivatives for efficient preferential CO oxidation in H2-rich stream

Microwave pyrolysis inherited the molecular-level engineering design of the CuCe-MOF: The tandem microwave pyrolysis firstly carbonized them to CuCe/C with topological structure, and improved the microwave absorption of MOFs in nitrogen atmosphere. Subsequently, CuCeO x catalyst was synthesized by its self-heating source of microwave in air, which endowed with molecular-level dispersed active sites to enhance preferential CO oxidation in H 2 -rich stream. • MOFs derivatives are achieved via tandem microwave pyrolysis. • Microwave pyrolysis inhibits the agglomeration of metal nanoclusters. • The tandem strategy solves the problem of poor microwave adsorption of MOFs. • Ligand carbonization provides dispersed heating sources by enhancing microwave absorption. • Microwave pyrolysis-engineered CuCeO x exhibits an outstanding performance of preferential CO oxidation. The versatile metal–organic framework (MOF) derivatives are achieved via microwave pyrolysis. The dipole vibration thermogenesis of molecules by microwave pyrolysis overcomes the issues of high energy consumption, slow heating rate, unregulated at the molecular-level, metal nanoclusters particles migration and coalescence caused by traditional thermal pyrolysis. For solving the poor microwave absorption of MOFs, a tandem microwave pyrolysis strategy is employed herein. Ligand carbonization enhances the conduction loss of microwaves and becomes a highly dispersed microwave heating source, which effectively inhibits the agglomeration. The CuCeO x catalysts obtained through this strategy retain the merits of bimetallic CuCe-MOFs with highly dispersed active species, and exhibit outstanding catalytic activities with the 100% conversion of CO being achieved at 75 °C for the preferential CO oxidation in H 2 -rich stream. These results demonstrate that the microwave pyrolysis-engineered MOFs uniformity has established catalyst with highly dispersed active species.

Engineering Metal-Organic Framework-based Nanozymes for Enhanced Biosensing

Background: Nanozymes are a kind of emerging nanomaterials that can mimic the catalytic activity of natural enzymes with good stability. Objective: Benefited by the unique coordination structure and constitution, metal-organic frameworks (MOFs) have been widely exploited as novel nanozymes. Importantly, various MOFs engineered with fascinating functions provide great opportunities to enhance their enzyme-like activity and improve their applied performance, achieving the goal of vividly mimicking natural enzymes. Conclusion: This review summarized recent advances in the fabrication of the MOFs-based nanozymes and their applications in biosensing. First, MOFs-based nanomaterials containing pristine MOFs, functionalized MOFs, MOFs-based composites and MOFs derivatives are introduced, where the design strategy, enzyme-like activity and the catalytic mechanisms are highlighted systematically. Then, their applications in various target assays are summarized. Finally, the challenges and possible research directions for the development and application of MOFs-based nanozymes are provided.

Static adsorption of MOFs nanosheets on 3D nanocubes for supercapacitor electrode materials

Metal-organic frameworks (MOFs) are of interest because of their excellent specific surface areas and pore structures. Two-dimensional (2D) nanosheets suffer from the disadvantages of random growth and easy agglomeration, which greatly limit their applications. This study combines nanosheets with structurally unique materials to improve their performance. Iron cobalt Prussian blue (FeCo-PBA) nanocubes of uniform size are synthesized at room temperature (25 ℃). Subsequently, the Prussian blue (PBA) surface is modified using sodium dodecyl sulfate to load Co-Ni-MOF nanosheets. This method enhances the adhesion of the nanosheets on the FeCo-PBA surface and improves the stability of the material. The PBA@Co-Ni-MOF is then vulcanized to fully activate the MOF metal species and obtain more active sites, and the sample PBA@CoS2/NiS2 is obtained. The obtained samples (PBA@CoS2/NiS2) are found to have good electrochemical performance. They exhibit an excellent specific capacitance of 1261 F g−1 (694 C g−1) at 1 A g−1. A hybrid supercapacitor consisting of activated carbon (AC) and PBA@CoS2/NiS2 composites as the cathode and anode, provide an energy density of 63 W h kg−1 at a power density of 837 W kg−1. The device exhibits outstanding cycle stability of 87% after 5000 cycles. The study demonstrates a flexible way to activate MOF to boost the performance of supercapacitor electrode materials. The static adsorption method maintains the stacking structure of clearly defined nanosheets while also enriching the active sites, which has potential for designing of MOF derivatives for energy storage devices.

Functionalized MOF-Derived Nanoporous Carbon as Compatible Nanofiller to Fabricate Defect-Free PDMS-Based Mixed Matrix Pervaporation Membranes.

Metal–organic framework (MOF)-based polydimethylsiloxane mixed matrix membranes applied for alcohol recovery with high permeability and selectivity are drawing more and more attention. However, the design and fabrication of high-quality and stable MOF-based mixed matrix membrane for pervaporation are still a big challenge. Herein, PDMS functionalized MOF-derived nanoporous carbon (P-ZNC) was first explored as compatible nanofiller to mutually blend with polydimethylsiloxane on PVDF substrate to fabricate defect-free mixed matrix membranes via dip-coating and thermal cross-linkng. Induced by UV illumination, hydrophobic modification of MOF-derived nanoporous carbon was successfully realized under mild conditions within one step, simplifying the operation step. By using this facile strategy, we can not only solve the existing problem of agglomeration, but also covalently cross-link MOF derivative with polymeric matrix and effectively eliminate the interface defect between polymer and nanoparticles without any extra steps. The method also gives a good level of generality for the synthesis of versatile stable nanoporous MOF-derived carbon-based mixed matrix membranes on various supports. The prepared PDMS/P-ZNC with commendable structures possessed excellent separation performance in low concentration n-butanol recovery and had a good balance between permeance, selectivity, and stability.

Selective electrooxidation of primary amines over a Ni/Co metal-organic framework derived electrode enabling effective hydrogen production in the membrane-free electrolyzer

The overall water electrolysis always needs an ion-conductive membrane to separate the generated hydrogen and oxygen from the corresponding cathode and anode, which improves the manufacturing cost of the electrolyzer. The substitution of thermodynamically more favorable organic oxidation reactions for oxygen evolution reaction avoids the requirement of the membrane, accompanied by the generation of value-added products at the anode. Herein, with the help of the bimetallic Ni/Co metal-organic framework derivative (t-Ni/Co MOF) as the anodic electrocatalyst, we develop an oxidant-free condition for the selective conversion of primary amines into nitriles. Specifically, aromatic and aliphatic nitriles can be conveniently obtained with good yields and faradaic efficiencies over the t-Ni/Co MOF electrode when coupling with the hydrogen evolution reaction. Notably, benzylamine can be oxidized into benzonitrile even at an ultralow potential of 1.30 V vs. reversible hydrogen electrode (RHE) over the t-Ni/Co MOF electrode, which is lower than that of the reported Ni-based monometallic electrocatalysts for benzylamine elecrooxidation. Control experiments suggest that the reversible electron transfer process of Co2+ ↔ Co3+ at a relatively low potential contributes to the formation of higher valence Ni species, which accelerates the kinetics of the primary amine oxidation, simultaneously reducing power consumption for hydrogen production.

Size-Dependent Oxidation-Induced Phase Engineering for MOFs Derivatives Via Spatial Confinement Strategy Toward Enhanced Microwave Absorption

HighlightsThe size of metal organic frameworks (MOFs) derivatives was manipulated by a spatial confined growth strategy.Dielectric polarization is the dominant dissipation mechanism due to the phase hybridization based on size dependent oxidation motion.The specific reflection loss of synthesized Co/Co3O4 hollow carbon nanocages surpasses most reported MOFs derived counterparts for practical microwave absorption applications.