Ni Metal-organic Frameworks Research Articles

High-loading LiBH4 Confined in Structurally Tunable Ni Catalyst-decorated Porous Carbon Scaffold for Fast Hydrogen Desorption.

Catalysts combined with nanoconfinement can improve the sluggish desorption kinetics and poor reversibility of LiBH4 . However, at high LiBH4 loading, their hydrogen storage performance is significantly reduced. Herein, a porous carbon-sphere scaffold decorated with Ni nanoparticles (NPs) was synthesised by calcining a Ni metal-organic framework precursor, followed by partial etching of the Ni NPs to fabricate an optimised scaffold with a high surface area and large porosity that accommodates high LiBH4 loading (up to 60 wt.%) and exhibits remarkable catalyst/nanoconfinement synergy. Owing to the catalytic effect of Ni2 B (formed in situ during dehydrogenation) and the reduced hydrogen diffusion distances, the 60 wt.% LiBH4 confined system exhibited enhanced dehydrogenation kinetics with >87% of the total hydrogen storage capacity released within 30 min at 375 °C. The apparent activation energies were significantly reduced to 110.5 and 98.3 kJ/mol, compared to that of pure LiBH4 (149.6 kJ/mol). Moreover, partial reversibility was achieved under moderate conditions (75 bar H2 , 300 °C) with rapid dehydrogenation during cycling.

MOF-derived spherical NixSy/carbon with B-doping enabling high supercapacitive performance

This work uses a simple Ni-metal organic framework (Ni-MOF) to generate a uniform metal-containing carbon hybrid structure of Ni/C by in-situ pyrolysis. Then, after NaBH4 treatment and hydrothermal vulcanization of Ni/C, multiphase B-doped NixSy nanoparticles can be obtained and uniformly anchored in the carbon skeleton, forming a highly porous flower-shaped B-NixSy/C composite. The positive role of B doping was theoretically confirmed by Density Function Theory (DFT) calculations. The MOF-derived carbon framework has porous, conductive, and continuous features beneficial for fast charge transfer. There are also multiple Ni-sulfide phases in B-NixSy/C, dominated by hexagonal NiS, hexagonal Ni2S3, and cubic Ni3S4, which give rich valance state and are expected to bring active electrochemical reactions. In addition, the boronation process by the reducing agent of NaBH4 is also proved beneficial to bring high capacitance, possibly due to the incorporation of more active sites by B. Therefore, the B-NixSy/C composite electrode delivers a high specific capacity of 1250.4 C g–1 at 1 A g–1 and excellent rate performance. The B-NixSy/C-based asymmetric supercapacitor also shows promising prospects for future energy storage devices, delivering high cyclability with capacitance retention of 87.6% after 7000 cycles. This work proves the efficiency of MOF-derived carbon framework and B-doping in improving metal sulfide's electrochemical performances.

Enhanced ammonia selectivity on electrochemical nitrate reduction: Cu–Ni metal–organic frameworks with tandem active sites for cascade catalysis

A Cu–Ni metal–organic framework is proposed as a cascade catalyst to eliminate the nitrite product in nitrate reduction, providing an effective route for high-value green ammonia synthesis.

Fe, S-uniformly dispersed Ni MOFs based on FeS substrate precipitation-dissolution equilibrium for water and seawater oxidation

In the pursuit of advancing electrocatalysts for alkaline oxygen evolution reaction (OER), the development of nickel-based metal–organic frameworks with a judicious balance of cost-effectiveness and catalytic efficacy is of paramount importance.

Synthesis of GO/Fe–Ni MOF octahedral structure as an effective magnetic adsorbent in the removal of sulfur compounds from liquid fuel

An effective composite of bimetallic metal-organic frameworks (MOFs) GO/Fe–Ni in the presence of a specified quantity of graphene oxide (1, 5, 10, 25, and 50 wt%) was synthesized via a solvothermal method for removal of thiophene (TP) from a model of oil. The efficiency of adsorption desulfurization was evaluated by removing TP from the n-heptane-TP as a model oil. XRD, FTIR, FESEM, EDS, BET, VSM, and TGA techniques were used to investigate and confirm the structural characteristics of the GO/Fe–Ni MOF composite. The composite material of GO to Fe–Ni MOF = 5 wt% with adsorption capacity of 18.54 mg. g−1 displayed the best performance in TP at the optimal experimental conditions, which was ascribed to its high porosity and suitable pore size. GO/Fe–Ni MOF adsorption has a surface area of (431 m2. g−1) higher than Fe–Ni MOF (352 m2. g−1), based on the BET technique, there would be more opportunity for TP to be adsorbed on the GO/Fe–Ni MOF. The reused tests prove that GO/Fe–Ni MOF can be recycled for at least four runs with negligible losses in its capacity performance (11%). More significantly, the magnetic properties of GO/Fe–Ni MOF (5 wt%) can be used to facilitate the separating of oils in harsh conditions.

Minireview: Ni–Fe and Ni–Co Metal–Organic Frameworks for Electrocatalytic Water‐Splitting Reactions

Electrolysis is one of the clean, environmentally friendly, and sustainable pathways to produce hydrogen for renewable energy storage. However, to make electrolysis a competitive technology for hydrogen production, developing nonprecious metal‐based catalysts for oxygen evolution reaction (OER) is mandatory. Several new classes of electrocatalysts are developed with outstanding OER catalytic activity, stability, and commercial viability. Owing to the structural diversity, porosity, and accessibility of catalytically active metal centers, nickel‐based metal–organic frameworks (MOFs) are intensively explored as OER catalysts. In particular, bi‐ and trimetallic Ni MOFs with Fe and Co as additional metal nodes show excellent OER activity which can be tailored through the fine tuning of the metal compositions. Herein, the current state of research in Ni‐based MOFs as OER catalyst materials for alkaline electrolysis is presented. Strategies to improve the catalytic performance like compositional variations, choice of synthetic routes, and support materials are presented. Furthermore, OER activities are compared and presented based on the performance metrics (current density, overpotential, and Tafel slopes). Finally, concluding remarks featuring the key findings in Ni‐based MOFs and the possible rooms for future developments are summarized.

Amino functionalized metal-organic framework/rGO composite electrode for flexible Li-ion batteries

Advanced electrode design is critical for the rapid development of flexible energy storage devices (ESD) in the emerging field of flexible electronics. Metal-organic frameworks ((MOFs) for lithium storage have attracted considerable attention. However, one of the main obstacles is their poor electronic conductivity, which restricts their cycling stability under redox conditions. Herein, we report a facile synthesis route to fabricate Ni(BDC-NH2)/reduced graphene oxide (rGO) composites employing the solvothermal method. Ni(BDC-NH2) MOFs exhibited a unique laminar and porous morphology, which helps with Li-ion diffusion, and thus enables faster electrode activation and capacitive controlled electrochemical activity. When freestanding Ni(BDC-NH2)/reduced graphene oxide (rGO) composite electrode was prepared via simple vacuum filtration. As anode material for lithium-ion batteries. It delivered a reversible capacity of 813 mAh g−1 at a current density of 200 mA g−1 after 100 cycles. More importantly, it also shows an excellent rate of performance compared to Ni(BDC)/rGO MOFs. The better electrochemical performance of Ni(BDC-NH2)/rGO is attributed to the unique chain network formed by the synergistic effect of multi-coordination of carboxylic oxygen and amino nitrogen with high theoretical capacities and rGO with high electrical conductivity.

In situ construction of metal-organic frameworks on chitosan-derived nitrogen self-doped porous carbon for high-performance supercapacitors

The intelligent use of regenerable and degradable biomass materials to substitute the synthetic materials can bring huge economic benefits and environmental improvements. In addition, metal-organic framework (MOF) based cathode materials are becoming a research hotspot for supercapacitors. Here, Co nanoparticle-modified nitrogen self-doped porous carbonized chitosan aerogel (CCA-Co) precursors were prepared by sol-gel, freeze-drying technique and carbonization process using biomass chitosan particles and cobalt compounds as raw materials. Then the layered composite (CCA-Co@MOF) was obtained by growing Co-doped Ni MOF (Co-Ni MOF) with CCA-Co precursor as the carrier. Notably, the presence of Co nanoparticles in carbonized chitosan aerogel (CCA) not only promotes the self-assembly of CCA and MOF, but also etched Co ions can participate in the growth of MOF, resulting in excellent electrochemical performance. Specifically, the specific capacitance of CCA-Co@MOF reaches 1877.2 F g−1, which is much superior to CCA-M@MOFs (M = Ni, Zn and Cu) and other contrast materials. Furthermore, the asymmetric supercapacitor (CCA-Co@MOF//AC ASC) assembled using CCA-Co@MOF and activated carbon (AC) electrodes, exhibits a high energy density (45.9 Wh kg−1 at 431.7 W kg−1). This work highlights the advantages of metal nanoparticle-modified and carbonized chitosan aerogels for MOF growth, demonstrating its great value in the field of electrochemical energy storage.

From waste to health: Application of MOF modified walnut biochars for the determination of twenty pesticides in wheat flour by ultra-high performance liquid chromatography-tandem mass spectrometry

In this research, walnut shell along with a Ni-metal organic framework (Ni-MOF) was thermally treated to obtain a highly efficient biochar. A µ-solid phase extraction (µ-SPE) setup containing the optimized walnut modified biochar was implemented for the extraction of 20 wheat specified pesticides with a wide range of polarities. The modified biochars were characterized and the role of Ni-MOF on the porosity of the obtained biochars was investigated. After optimizing the extraction parameters, the 50 %-Ni-MOF-walnut shell biochar was selected. Accordingly, the precision for intra-day (2.4–25 %), inter-day (7–28.3 %) and synthesis procedure (4.1–26.7 %) was calculated. The limits of detection and quantification were in the range of 0.01–12.1 µg/L and 0.03–40.5 µg/L, respectively. This method was applied for the analysis of 29 wheat samples. The risk assessment study demonstrates that the contaminated wheat samples cannot cause non-carcinogenic harm to adults but might have an impact on children.

Proton conductive properties of a substituted imidazole dicarboxylate-based hydrogen-bonded organic framework and a related nickel-organic framework

The acquisition of proton conductive hydrogen-bonded organic frameworks (HOFs) and metal-organic frameworks (MOFs) has recently received sustained attention. In this paper, 2-(p-N-imidazole)phenyl-1H-4,5-imidazole dicarboxylic acid (p-IPhH3IDC) was employed to solvothermally synthesize a 3D HOF, [p-IPhH3IDC]·2H2O (1), and a 3D Ni(II) MOF, {[Ni(p-IPhH2IDC)2]·H2O}n (2). Their crystal structures have been characterized by single-crystal X-ray diffraction. By means of thermogravimetric analysis, X-ray powder diffraction, and scanning electron microscopy determinations, it was confirmed that both compounds have excellent thermal and water stability. Subsequently, their proton conductive properties were tested by AC determinations. It was found that their proton conductivities increased with the rising humidity and temperature. At 100 ​°C and 98% RH, the optimal proton conductivities are 1.06 ​× ​10−5 ​S ​cm−1 for 1 and 3.97 ​× ​10−5 ​S·cm−1for 2. Finally, the proton-conducting mechanisms of the two compounds were deduced. This work offers new inspiration for the exploration of novel proton-conductive materials.

Robust bimetallic metal-organic framework cathode catalyst to boost oxygen reduction reaction in microbial fuel cell

Metal-organic frameworks (MOFs) have emerged as versatile materials for widespread energy and environmental applications due to their intrinsic physical and chemical properties. To this extent, this research is focused on the synthesis of novel amine-functionalized single (Zr) and bimetallic (Zr, Ni) MOF viz. NH2-UiO-66(Zr) and NH2-UiO-66(Zr/Ni), followed by their testing as cathode catalysts to improve oxygen reduction reaction (ORR) in a microbial fuel cell (MFC) for bioenergy recovery from organic wastes. The physical and chemical characterization techniques depicted the successful synthesis of octahedral-shaped MOF nanoparticles with similar structural integrity despite the incorporation of the secondary metal ion. However, electrochemical analyses demonstrated NH2-UiO-66(Zr/Ni) as a better catalyst, achieving a high ORR peak current, low charge transfer resistance, and high diffusion coefficient as compared to both NH2-UiO-66(Zr) and 10% Pt-C catalyzed cathodes. MFC performance evaluation further confirmed the high catalytic activity of NH2-UiO-66(Zr/Ni), allowing to recover a power density (PD) of 0.8 W/m2 at a coulombic efficiency (CE) of 75.4%, outperforming the MFC using 10 % Pt-C catalysed cathode. This study suggests that the NH2-UiO-66(Zr/Ni) can be used as an efficient ORR catalyst for application in large-scale MFCs.

Ultrathin binary MOF nanozyme with boosted activity via introduction of active iron sites for detecting sulfide ion

Convenient and reliable sulfide ion (S2-) detection is necessary due to its harmfulness. Herein, a new colorimetric sensing platform for S2- was established based on the binary NiFe metal-organic framework (MOF) nanozyme. The tremella-like NiFe MOF with ultrathin nanosheets was synthesized via introduction of active Fe sites in the Ni MOF by a rapid microwave-assisted method just in 11 min. The ultrathin NiFe MOF exhibited 2.8-fold higher peroxidase-like activity and 42.5-fold higher affinity to H2O2 than the Ni MOF, which could efficiently catalyze the decomposition of H2O2 into hydroxyl radicals (•OH) and superoxide anion radicals (O2•−) for the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB). The DFT study reveals that the dissociation energies of H2O2 and adsorption energies of reactive oxygen intermediates on Fe sites are more negative than those on Ni sites, proving the crucial role of Fe sites in the elevated peroxidase-like activity of NiFe MOF. By taking advantage of the unique redox reaction between H2O2 and S2-, a simple and sensitive colorimetric method for S2- was proposed based on TMB/H2O2/NiFe MOF system with a wide linear range of 0.5 – 60 μM and a low detection limit of 28 nM (3σ). The proposed NiFe MOF-based colorimetric method exhibited good selectivity to S2- among some common cations and anions, and it was successfully applied in the real water samples.

Electrospun nanofibers modified with Ni-MOF for electrochemiluminescent determination of glucose

A novel electrochemiluminescence (ECL) sensor for glucose detection was constructed by covering Au nanoparticles (Au NPs), Ni metal–organic frameworks nanofibers (Ni-MOF NFs) and glucose oxidase (GOD) on the electrode surface, respectively. Ni-MOF NFs prepared by electrostatic spinning can be used as GOD carrier and ECL promoter. Meanwhile, synergistic effect of Ni-MOF NFs and Au NPs could amplify the ECL signal of Ru(bpy)32+-TPrA system. With the increasing of glucose concentration, ECL signal was also increasing, so a method for determining glucose could be established. The possible mechanism of luminescence was investigated, and the parameters affecting the experimental reaction were also studied. Under the optimal conditions, the constructed ECL sensor can effectively detect glucose in the range of 2.0 × 10−10 to 2.0 × 10−5 M, and the detection limit was 6.7 × 10−11 M. This study demonstrated for the first time that Ni-MOF NFs could serve as ECL accelerator for the facile detection of glucose in human serum.

One-Dimensional Co-Carbonate Hydroxide@Ni-MOFs Composite with Super Uniform Core-Shell Heterostructure for Ultrahigh Rate Performance Supercapacitor Electrode.

The insufficient contact between two phases in the heterostructure weakens the coupling interaction effect, which makes it difficult to effectively improve the electrochemical performance. Herein, a Co-carbonate hydroxide@ Ni-metal organic frameworks (Co-CH@Ni-MOFs) composite with super uniform core-shell heterostructure is fabricated by adopting 1D Co-CH nanowires as structuredirecting agents to induce the coating of Ni-MOFs. Both experimental and theoretical calculation results demonstrate that the heterostructure plays a vital role in the high performance of the as-prepared materials. On the one hand, the construction of super uniform core-shell heterostructure can create a large number of interfacial active sites and take advantages of the electrochemical characteristics of each component. On the other hand, the heterostructure can increase the adsorption energy of OH- ions and promote the electrochemical activity for improving the reversible redox reaction kinetics. Based on the aforementioned advantages, the as-fabricated Co-CH@Ni-MOFs electrode exhibits a high specific capacity of 173.1 mAh g-1 (1246 F g-1 ) at 1 A g-1 , an ultrahigh rate capability of 70.3% at 150 A g-1 and excellent cycling stability with 90.1% capacity retention after 10 000 cycles at 10 A g-1 . This study may offer a versatile design for fabricating a MOFs-based heterostructure as energy storage electrodes.

Selective Hydrodeoxygenation of Lignin and Its Derivatives without Initial Reaction Pressure Using MOF-Derived Carbon-Supported Nickel Composites

In this study, Ni-metal–organic frameworks (MOFs) were used as precursors to obtain carbon-supported nickel composites (Ni@C) after calcination. The hydrodeoxygenation properties of the model compound and corncob lignin were investigated without an external hydrogenation source and initial pressure. Additionally, the effect of Ni@C on degradation of model compounds, corncob lignin, and benzyl phenyl ether (BPE) under different conditions was examined. The results showed that with isopropanol as the in situ hydrogen source, the conversion percentage of BPE was 90.2% and the yield of phenol was 88.3 wt % at 150 °C. The catalysts were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), NH3 temperature-programmed desorption (NH3-TPD), X-ray photoelectron spectroscopy (XPS), and thermogravimetry (TG), and the lignin and bio-oil were characterized by gas chromatography–mass spectrometry (GC–MS) and two-dimensional heteronuclear single quantum coherence (2D-HSQC). It was found that the Ni@C catalyst with well dispersion, high support rate, and rich acid sites was successfully synthesized. In the process of degradation, the C–O ether bond in the structure of lignin was successfully broken to generate the phenolic monomer, and the high-efficiency hydrodeoxygenation of lignin was realized under mild conditions.

Metal–organic framework derived magnetic carbon Ni@C octahedron composite as an excellent microwave absorber

Metal–organic framework (MOF)-derived magnetic carbon composites have become ideal candidates as high-performance microwave-absorbing materials. Herein, the MOF-derived Ni@C octahedron composite was synthesized via a facile solvothermal reaction and annealing treatment, which involved a material transition process from the Ni–MOF into the magnetic Ni@C composite. The structural, morphological, magnetic, and electromagnetic (EM) properties of as-prepared MOF-derived Ni@C materials were determined. Given the MOF template and controlled carbonized treatment, the obtained micro-scale Ni@C octahedron showed adjustable EM parameters and EM wave absorption property by adjusting the addition amount. The optimized reflection loss value of MOF-derived Ni@C reached −51.9 dB at 10.5 GHz at 2.5 mm thickness, and the composite had broadband microwave attenuation and covered 5.6 GHz from 8.9 GHz to 14.5 GHz. Given the good impedance matching, special spatial structure, and synergy effect between magnetic and dielectric losses, this MOF-derived magnetic carbon Ni@C octahedron composite is expected to be a potential EM wave-absorbing material.

Hierarchical NiCo2O4 nanostructured arrays decorated over the porous Ni/C as battery-type electrodes for supercapacitors

The rational construction of hierarchical electrode materials has always been an attractive strategic development in energy storage. In this paper, the porous Ni/C (NC) substrate, which is derived from Ni metal–organic frameworks (Ni-MOFs), is served as the conductive skeleton on Ni foam (NF) for supporting two different morphologies NiCo2O4 nanostructure arrays (NiCo2O4/NC). The hierarchical layered nanomaterial utilizesthe porous NC substrate as “favorable skeleton” for electron transfer and is coupled to vertical well-organized NiCo2O4 nanoarrays to improve specific capacitance of composites. Benefits from the advantages of hierarchical layered structure, the electrochemical properties of as-constructed NiCo2O4/NC with two different morphologies were better than those of pure NiCo2O4 prepared under the same conditions. Moreover, the optimized NiCo2O4 nanowires arrays on NC substrate (NiCo2O4NWs/NC) electrode acquire prominent specific capacitance of 1945.9 F g−1 (270.3 mAh g−1) at 1 A g−1 and good rate performance. Additionally, the assembled asymmetric device by NiCo2O4NWs/NC and carbon nanotube (CNT) displays a high energy density of 58.31 Wh kg−1 at a power density of 749.7 W kg−1, as well as good cyclic stability. The remarkable properties manifest that the hierarchical NiCo2O4NWs/NC electrode has a good prospect in electrochemical applications.

Three-dimensional FeMZn (M = Co or Ni) MOFs: Ions coordinated self-assembling processes and boosting microwave absorption

Herein, we construct two metal–organic frameworks (MOFs) composite nanoflowers (NFs) with anisotropic binary assembled structures by a facile one-pot method. Different from the two-step epitaxial growth method, the anisotropic assembly of the binary MOFs (MOF-5 and MIL-88B) in the mixed system can be realized without preparing the template MOFs. The ions coordinated self-assembling behaviors during the formation of the three-dimensional (3D) structure are clarified. The absorbing mechanisms of the derivative absorber are elucidated. The results indicate that the special hierarchical assembled structure endows absorbers with rich heterogeneous interfaces, porous structure, suitable impedance matching and complementary loss mechanisms. The optimized absorbers FeCoZn@C NFs and FeNiZn@C NFs exhibit outstanding microwave absorption performance. Only with a matching thickness of 1.9 mm, the effective absorbing bandwidth (EAB, reflection loss (RL) < −10 dB) of the absorber covers 6.0 GHz (12–18 GHz, the entire Ku band). The minimum reflection loss (RLmin) reaches −53.1 dB (loss of electromagnetic waves above 99.999%). This study might shed light on the preparation of high-performance microwave absorbers with sophisticated structures.

Significantly lowered activation energy in proton conductor by Mg substitution in a layered Ni metal-organic framework.

Designs and developments of proton conductors are highly important in chemistry and energy fields. In this study, a novel metal-organic framework H2DAB-MgNi(ox)3 was synthesized. X-ray powder diffraction, scanning transmission electron microscopy, and scanning transmission electron microscopy-energy-dispersive X-ray mapping measurements demonstrated that the H2DAB-MgNi(ox)3 had a solid-solution structure, with the homogeneous distribution of Mg and Ni elements. The proton conductivity of H2DAB-MgNi(ox)3 was enhanced from that of H2DAB-Ni2(ox)3 at 95% relative humidity by Mg substitution.

MOFs derived flower-like nickel and carbon composites with controllable structure toward efficient microwave absorption

Controlling the structure of microwave absorption materials to ameliorate the microwave absorption performance is attracting extensive interest. Here, the flower-like nickel and carbon composites are fabricated by using metal organic frameworks (MOFs) as sacrificial precursors. By simply changing the conditions of the solvothermal reaction, the structure of flower-like Ni MOF precursors evolve from solid to yolk-shell and hollow. After annealed at 600 °C under Ar atmosphere, the resultant hollow flower-like nickel and carbon composite displays strongest reflection loss of −59.38 dB and the effective absorption bandwidth is 5.22 GHz at thickness of 3.0 mm. More importantly, the effective absorption bandwidth is as wide as 6.4 GHz at thickness of 2.4 mm. The synergistic effect of hollow and flower structure help to improve the polarization and stimulate the multiple reflections and scattering of electromagnetic waves. This work confirms that the design of microstructure is a promising route to moderate the microwave absorption performance.