Nickel-based Metal-organic Framework Research Articles

Probing the effect of electrolyte ions on the electrochemical performance of nickel-based metal-organic frameworks

Probing the effect of electrolyte ions on the electrochemical performance of nickel-based metal-organic frameworks

One-pot synthesis of 2D-Ni-MOF from waste PET plastic in aqueous medium for selective electrooxidation of glycerol, ethanol, and methanol

This study investigates the electrochemical performance and selectivity of a nickel-based metal-organic framework (Ni-MOF) catalyst synthesized from waste PET plastic using a one-pot approach in aqueous media. The Ni-MOF electrode was evaluated for glycerol electrooxidation reaction (GEOR), ethanol electrooxidation reaction (EEOR), and methanol electrooxidation reaction (MEOR). Linear sweep voltammetry (LSV) revealed current densities of 30mA/cm² at 0.5639V for GEOR, 50.07mA/cm² at 0.35V for EEOR, and 45.73mA/cm² at 0.39V for MEOR, indicating superior catalytic activity. Nyquist plots showed lower charge transfer resistance (Rct) values of 11.0 Ω for GEOR, 2.79 Ω for EEOR, and 2.69 Ω for MEOR, confirming efficient electron transfer. Bode impedance plots demonstrated lower impedance for alcohol electrooxidation compared to oxygen evolution reaction (OER). Chronoamperometry (CA) tests indicated excellent stability with 75.72% glycerol conversion for GEOR and selectivities of 94% for glyceric acid, 65.59% for acetic acid in EEOR, and 70.54% for formic acid in MEOR. These results highlight the potential of Ni-MOF derived from recycled PET plastic for sustainable and efficient electrooxidation of C1-C3 alcohols.

Facile interface engineering of highly stable covalently functionalized graphene oxide-nickel based metal organic framework heterostructures for supercapacitor applications

This study presents the synthesis, characterization and electrochemical studies of the covalently connected 2D/2D heterostructures of nickel-based metal-organic framework (Ni-MOF)/graphene oxide (GO) hybrids. The covalent linkage in GO plays a vital role in the growth of Ni-MOF onto the functionalized GO and these hybrids (NG) show fascinating structural properties. An appreciable reduction of GO is observed in NG hybrids with an increase in Ni-MOF concentration. The NG hybrids display exceptional structural stability with a maximum of 96 % capacitance retention even after 10,000 cycles and augmented electrochemical performance (151.8 F g-1 at a current density of 0.5 A g-1).

Synthesis and investigation of charge storage characteristics in Ni-MOF/PANI composite as an active electrode material for supercapacitor

This study aimed to develop a more stable and efficient energy storage device, synthesis of nickel-based pristine metal organic framework (MOF) and combined it with the emeraldine base phase of polyaniline (PANI) which is confirmed with XRD, SEM and TEM. Both Ni-MOF and PANI exhibit faradaic (battery-like) behaviour. However, when these two materials are combined, the stability of the resulting material is enhanced. The initial materials, MOF and PANI, exhibit specific capacities of 42 C/g and 72 C/g, respectively. However, when these two materials are combined, their composite exhibits an enhanced specific capacity of 122 C/g. The cyclic voltammetry (CV) analysis shows oxidation and reduction peaks, indicating faradaic behaviour. This behaviour is further confirmed by electrochemical impedance spectroscopy (EIS). Upon comparing it with prior results, the specific capacity appears to be slightly lower. However, it is anticipated to exhibit stronger stability, which is contradictory. The composite material (Ni-MOF/PANI) exhibits remarkable capacitive retention of 99.25 % even after undergoing 5000 cycles, as anticipated. In order to validate the aforementioned findings and determine the extent of the current contribution from capacitive and diffusive control, Dunn's model was employed. The data demonstrates the prevalence of diffusive-controlled (faradaic) current over capacitive current. The highest proportion of current resulting from diffusion is 96 %, achieved at a scan rate of 5 mV/s. The highest proportion of current resulting from capacitance is 24 %, achieved at a scan rate of 300 mV/s. At lower scan rates, the material exhibits a greater faradaic behaviour, whereas at higher scan rates, there is a progressive increase in non-faradaic processes. The insufficient time for diffusive process at higher scan rates is the cause. The Dunn's model with quadratic correction is also performed and comparative results were shown. Overall, the material exhibits more stability and dominance in the faradaic process, which paves the path for improved performance.

Piperazine pyrophosphate-functionalized Ni-MOF metal framework: Fabrication and synergistic explosion suppression mechanisms

Dust explosion suppression is crucial for ensuring safe industrial operations. To explore composite explosion suppression powders with higher performance, piperazine pyrophosphate (PAPP)-functionalized nickel-based metal–organic framework (PAPP@Ni-MOF) synergistic suppression materials were designed and synthesized. The effectiveness of this suppressant in inhibiting the explosion flame and intensity of polypropylene (PP) dust was investigated using explosion flame propagation and explosion pressure test apparatus. The results indicate that the combination of N/P elements and Ni-MOF exhibits excellent catalytic carbonization performance. Adding 50 wt% PAPP@Ni-MOF can completely inhibit the propagation of PP explosion flames and the rise in explosion pressure. The maximum propagation distance of the explosion flame was reduced by 78.07 %, the overall flame propagation speed decreased by 84.54 %, and the maximum explosion pressure was reduced by 76.87 %. Through characterization experiments, the products before and after the explosion were analyzed. Combined with molecular dynamics (MD) simulation results, the efficient synergistic explosion suppression mechanism of PAPP@Ni-MOF for PP dust was revealed from the perspectives of thermal conduction isolation, key radical recombination, and volatile gas adsorption.

Enhancing the charge storage capacity of ultrathin metal–organic framework nanosheets with CO2-derived carbon nanotubes

Metal-organic frameworks (MOFs) hold promise as efficient electrode materials for supercapacitors, but their practical application is hindered by the intrinsic low electrical conductivity. Here, we employ CO2-derived carbon nanotubes based on molten salt electrolysis (MSE-CNTs) as the framework to guide the growth of nickel-based MOF (Ni-MOF). The resulting MSE-CNTs/Ni-MOF composite exhibits an impressive specific capacitance of 1714.2 F g−1 at 1 A g−1, 1.45 and 1.26 times greater than bare Ni-MOF (1185.7 F g−1) and CVD-CNTs/Ni-MOF (1364.3 F g−1, the composite of Ni-MOF and commercial CNTs produced by chemical-vapor-deposition), respectively. Moreover, the assembled hybrid supercapacitor (MSE-CNTs/Ni-MOF//active carbon) achieves a remarkable specific capacitance of 136.5 F g−1 at 1 A g−1 and an energy density of 54.8 Wh kg−1 at 850 W kg−1, standing among the best of the state-of-the-art. The superior capacitive performance of MSE-CNTs/Ni-MOF than CVD-CNTs/Ni-MOF can be attributed to the better electrical conductivity of MSE-CNTs, the thinner nanosheet architecture of MSE-CNTs/Ni-MOF, and the effective electrically conductive network within the composite. This work marks a paradigm shift from greenhouse gas CO2 to excellent energy storage materials, paving the way for addressing both the energy and climate issues simultaneously.

MOF-Derived Ni/NiO-C Nanocomposites as Bifunctional Electrocatalysts Capable of Driving Both ORR and OER.

Bifunctional electrocatalysts, capable of efficiently driving both the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER), are crucial for advancing electrochemical processes. While noble-metal-based catalysts are widely recognized for their role in oxygen processes, current state-of-the-art designs are limited to either ORR or OER activity, presenting a notable research gap. In addressing this challenge, we have developed a novel Ni/NiO-C nanocomposite catalyst derived from a nickel-based metal-organic framework (Ni-SKU-5). For the ORR, the Ni/NiO-C catalyst exhibits an onset potential of 0.95 V vs RHE in a 1.0 M KOH solution, coupled with a Tafel slope of -99 mV dec-1 at 1600 rpm. Moreover, the catalyst displays excellent stability, maintaining a performance of over 90% after 10 h of continuous reaction. Furthermore, the catalyst proves effective in the OER, boasting an overpotential of 370 mV (at 10 mA cm-2) and a Tafel slope of 114 mV dec-1, highlighting its bifunctionality. The bifunctional overpotential of the Ni/NiO-C composite is measured at 820 mV, surpassing that of the 20% Pt/C electrocatalyst (860 mV), highlighting its potential for practical applications. Comparative experiments establish the origin of the robust bifunctional reactivity toward the conformal hybrid structure, porous framework, and the synergistic effect operating among the constituents of the nanocomposite.

Enhanced peroxidase-like activity via Pt loading of Ni-MOF for colorimetric and smartphone-based bimodal determination of antioxidant capacity in aging cells

Total antioxidant capacity (TAC) serves as a vital indicator for evaluating cell senescence. Here, we synthesized a platinum-loaded nickel-based metal–organic framework material (Ni-MOF@Pt) via a solvothermal method for bimodal determination of TAC in aging cells. The Pt nanoparticle incorporation substantially enhanced the peroxidase-like catalytic activity of Ni-MOF. Ni-MOF@Pt exhibited a strong affinity for 3,3′,5,5′-tetramethylbenzidine (TMB) and H2O2, with lower Km values compared to horseradish peroxidase (HRP). The Ni-MOF@Pt-TMB-H2O2 system was successfully applied for detecting antioxidants, including glutathione (GSH), ascorbic acid (AA), and cysteine (Cys) with impressive detection limits (121 nM for GSH, 119 nM for AA, 72 nM for Cys), highlighting the high sensitivity of this system. Additionally, a smartphone-assisted visual detection sensor was established using Ni-MOF@Pt for rapid, sensitive, and on-site TAC detection. Moreover, our established Ni-MOF@Pt method effectively determined the TAC of aging cells and demonstrated its ability to differentiate between normal, senescent, and cancerous cells. This research offers novel insight on fabricating nanozymes with potent peroxidase-like properties and manifests their practicality in TAC analysis.

Integrating carbon quantum dots with oxygen vacancy modified nickel-based metal organic frameworks for photocatalytic CO2 reduction to CH4 with approximately 100 % selectivity

Solar-light-driven reduction of CO2 into renewable fuels has great potential in the production of sustainable energy, addressing the energy crisis and environmental problems simultaneously. However, it is a significant challenge to achieve high selectivity for the conversion of CO2 into CH4, which is a type of fuel with a high calorific value. Herein, carbon quantum dots (CQDs) were integrated with an oxygen vacancy modified nickel-based metal organic frameworks (NiMOFs) to form the CQDs-X/NiMOFV series, which exhibited superior performance for CO2 photoreduction into CH4 compared with pure NiMOFs in the presence of hole scavengers under visible light irradiation. The highest yielding rate of CH4 (1 mmol g−1 h−1) and selectivity (97.58 %) were obtained using a CQDs-25/NiMOFV catalyst. Most importantly, in diluted CO2 atmosphere, the yield of CH4 was almost unchanged and the selectivity of CH4 over CQDs-25/NiMOFV was higher than that in pure CO2. The superior performance of CQDs-25/NiMOFV may be attributed to the following two factors: (i) both CQDs and oxygen vacancies facilitate the transmission of electrons to promote the eight-electron reaction producing CH4, and (ii) oxygen vacancies can act as the electron trap to capture the photogenerated electrons to react with adsorbed CO2 on Ni2+. This study offers a valuable strategy for designing efficient photocatalysts to convert CO2 into CH4 with superior selectivity.

Architecting hydrogen-bonded and π–π conjugated MOF@NiPc networks towards enhanced energy storage

High-capacity metal–organic framework materials is constrained by their poor electron transport and unstable in aqueous. Herein, a spherical cobalt–nickel-based metal–organic framework (CoNi-MOF) micro-architecture with 18-π aromatic electron system of nickel phthalocyanine (NiPc) nanorods has been designed. In this system, intermolecular hydrogen (H) bonds between O in CoNi-MOF and H in nickel phthalocyanine (NiPc), along with longitudinal π-π stacking structure, could improve electron transport and structuralstability of MOFs. Benefiting from the 3D electron transport highways and “locking” effect of H bonds along with longitudinal π-π stacking structure, the optimized CoNi-MOF@NiPc electrode exhibits remarkable specific capacity of 807.365C g−1 at current density of 1 A/g, along with great cycling stability with 96.19 % capacity retention after 5000 cycles at 5 A/g, which is superior to the individual components. Besides, CoNi-MOF@NiPc//AC hybrid supercapacitor has been fabricated, which displays a maximum energy density of 130.68 Wh kg−1 at 962.09 W kg−1 and excellent cyclability (93.58 % capacity retention after 10,000 cycles). This study opens a new avenue for the design of organic electrodes and provides a new insight into H bond and π-π stacking structure effect toward advanced energy storage materials.

Synthesis and characterization of nickel-based MOFs: Enhancing photocatalysis and targeted cancer drug delivery

Metal–organic frameworks (MOFs) are intricate molecular solids formed by connecting organic ligands with metal or metal–cluster binding sites. They have exceptional characteristics such as expansive surface area, adaptability, and meticulously structured porosity, rendering them valuable in various applications including photocatalytic degradation and drug delivery systems. In this investigation, a benign Ni-based MOF was synthesized using benzene 1,4dicarboxylic acid as a linker and dimethyl sulfoxide as a solvent through the hydrothermal approach within a Teflon autoclave. The synthesized MOFs were precisely characterized using techniques such as X-ray diffraction, scanning electron microscope with energy-dispersive X-ray analysis, Fourier-transform infrared (FTIR) spectroscopy, thermogravimetric analysis, and N2-sorption measurements. The photocatalytic efficiency of the Ni-based MOF was explored against Congo red under visible light exposure, with the proposed mechanism involving electron transfer from photoexcited organic ligands to metallic clusters, resulting in a degradation efficiency of 98.68 % after 145 min. Furthermore, the Ni-based MOFs, when loaded with the anticancer drug cisplatin, displayed notable capabilities in drug delivery against the human breast cancer cell line MDA-MB-231, leading to a 35.26 % reduction in cell viability. Cytotoxicity assessments using the MTT assay revealed that the nano-carriers hindered cell proliferation with an IC50 value of 46.84 μg/mL.

Construction of negative electrostatic sugared gourd pore within nickel-based metal-organic framework for one-step purification acetylene from ethylene and carbon dioxide mixture

The development of highly efficient adsorbents for purifying acetylene from multi-component mixtures is crucial in the chemical industry, yet the tradeoff between renewability and selectivity severely constrains practical industrial applications. This study introduces sugar gourd pore framework (SGPF-1), an innovative ultra-microporous framework synthesized using 1,2-di(4-pyridyl)ethylene (BPE), 4,4′,4′’-nitrilotribenzoic acid (NTA), and hexanitronickel under solvothermal conditions. The X-ray diffraction analysis has been used to prove the detailed structure and phase purity of SGPF-1. The structure of SGPF-1 was tailored for selectively adsorbing and separating the target compound, C2H2. The negative electrostatic effect, inspired by the natural sugared gourd structure, enhances the selectivity and adsorption capacity for C2H2, while minimizing the interaction with impurities like C2H4 and CO2. Experimental data show that SGPF-1 exhibits significantly higher adsorption of C2H2 compared to C2H4 and CO2 at 298 K and 100 kPa, demonstrating exceptional selectivity towards 50/50 C2H2/CO2 and 1/99 C2H2/C2H4 to be 7.33 and 15.46. Breakthrough experiments confirm its effectiveness in separating C2H2 from C2H4/CO2 mixtures, with C2H4 saturation reached within 5 to 15 min, while C2H2 retention time at 298 K was as long as 26 min. Theoretical calculations have revealed that SGPF-1 exhibits electrostatic compatibility with C2H2 while repelling C2H4 and CO2 through an electrostatic exclusion mechanism. This highlights the importance of rational pore engineering in optimizing the electrostatic properties of adsorbents for high-efficiency multi-component separations. The research aims to advance gas separation technologies and improve the purity of acetylene, a valuable industrial raw material.

Synthesis of nickel-based metal organic framework using simplified solvothermal method

Synthesis of nickel-based metal organic framework using simplified solvothermal method

Nickel-Based Metal-Organic Framework Materials with Mixed Ferrocene-Based Ligands As Anodic Catalysts for Water Electrolysis and Urea Electrolysis

Water electrolysis is a highly promising technology for hydrogen production, generating green hydrogen with no greenhouse gas emissions. The water electrolysis reaction involves two half-reactions: hydrogen evolution and oxygen evolution. While oxygen evolution in water electrolysis involves a four-electron transfer requiring higher overpotential and thus leading to energy consumption. Urea electrolysis offers lower theoretical energy consumption than water electrolysis, making them a key technology in future electrolytic hydrogen production processes. Conventional anodic catalysts, such as Ir and Ru, exhibit good performance in oxygen evolution, but being precious metals, they face limitations due to high cost and limited abundance. Its is crucial to find an active, durable and cost-effective anode catalyst for realistic application.Metal-organic framework (MOF) materials, due to their high porosity, large surface area, and unique structural features, have emerged as promising materials for water electrolysis. However, their relatively poor stability is a drawback that needs to be overcome. In herein, we design the mixed ligand strategy for synthesizing the MOF materials. Ferrocene-based ligands, ferrocenedicarboxylic acid (Fd), combing with terephthalic acid (H2BDC) as the mixed ligands for this study. The MOF catalysts, namely Ni-BDC and Ni-BDC-Fd, was synthesized using a simple one-step hydrothermal method with ferrocenedicarboxylic acid and terephthalic acid.Raman spectra revealed the presence of Fe-O, originating from the iron in Fd, demonstrating a structural transformation during the hydrothermal process. XRD analysis also confirmed the existence of FeO. The SEM images showed nanosheets and nanoneedles morphologies for Ni-BDC, while a dense nanofiber structure for Ni-BDC-Fd demonstrating the effect of 2nd ligand on the MOF structure.Electrochemical tests were conducted in 1 M KOH electrolyte and 1 M KOH + 0.5 M urea electrolyte, including oxygen evolution reaction (OER), urea oxidation reaction (UOR). The overall reaction comprising the same catalysts for the anode and the cathode side is performed to examine the real electrolysis performance.Results showed that the addition of Fd enhanced OER and UOR activity in alkaline and urea electrolytes. Ni-BDC-Fd achieved 1.483 V vs. RHE and 1.386 V vs. RHE at 65 mA/cm-2 driving potential for OER and UOR, respectively, requiring a smaller potential than Ni-BDC to achieve the same current density. To verify that the performance improvement was not solely due to iron, NiFe-BDC was synthesized by adding iron nitrate, showing inferior UOR performance compared to Ni-BDC-Fd but superior OER performance to NiFe-BDC. This indicated that the performance improvement resulted from structural changes rather than just the presence of iron atoms. Ni-BDC-Fd exhibited the lowest Tafel slope in OER, indicating a faster reaction rate due to the increased active surface area during OER. After continuous catalysis for 80 hours in the alkaline water electrolysis cell and urea electrolysis cell, a significant improvement in the loss of potential was observed.These results suggest that the addition of ferrocene dicarboxylic acid altered the structure of Ni-BDC, maintaining an appropriate interlayer distance. This not only enhanced its catalytic performance but also improved its catalytic stability, demonstrating a promising strategy for preparing metal-organic framework materials for electrocatalysis applications. Figure 1

Effect of hydrochloric acid on the properties of Ni-MOF nanostructures as supercapacitor electrode materials

In this paper, we investigate the effect of hydrochloric acid on the energy storage characteristics of nickel-based metal–organic framework (Ni-MOF) nanostructures. Electrochemical tests reveal that Ni-MOF exhibit high capacitance under hydrochloric acid regulation, achieving a current density of 2567.23 F/g at 2 A/g in 1 ml. Additionally, the synthesized Ni-MOF demonstrate low electrical resistance, with a resistance (Rs) of 1.209 Ω at a hydrochloric acid volume of 1 ml. After 5000 cycles of galvanostatic charge–discharge testing, the cycle retention efficiency of Ni-MOF-0.5 ml remains at 85.71 %.

Real direct urea fuel Fell operation using standalone Ni-based metal-organic framework prepared by ball mill at room temperature

Climate change and health issues are exacerbated by fossil fuel use. Efficient environmental energy conversion devices can reduce these effects. For the first time, we used a simple ball milling approach to manufacture a Nickel-based metal-organic framework (Ni-MOF) at ambient temperature directly onto a carbon cloth surface (Ni-MOF/CC) for a direct urea fuel cell (DUFC) anode. The prepared materials' crystaline structure, surface topography, and elemental content were studied using X-Ray diffraction and a scanning electron microscope with an EDS analyzer. Cyclic voltammetry, impedance electrochemical spectroscopy, and chronoamperometry were used in a three-electrode cell configuration to evaluate the material's electrochemical oxidation efficiency, particularly toward urea. In-Situ, under real fuel cell operation circumstances, we tested the electrodes in a two-electrode cell configuration. The Ni-MOF/CC exhibited a 0.35 V onset potential owed to Ni(OH)2 (Ni+2)/Ni+3 NiOOH active site. The electrode was stable for urea oxidation and operated well under real fuel cell conditions, producing 5 mW/cm2 using 1 M urea. The Ni-based MOF's fast charge and mass transfer capabilities, which was directly synthesized onto the carbon cloth surface, make the produced electrode operate well compared with bare carbon cloth. The results of the current work allow for more efficient environmental energy conversion devices that will reduce global warming.

Bridging Nickel-MOF and Copper Single Atoms/Clusters with H-Substituted Graphdiyne for the Tandem Catalysis of Nitrate to Ammonia.

Interfacial engineering of synergistic catalysts is one of the keys to achieving multiple proton-coupled electron transfer processes in nitrate-to-ammonia conversion. Herein, by joining ultrathin nickel-based metal-organic framework (denoted Ni-MOF) nanosheets with few-layered hydrogen-substituted graphdiyne-supported copper single atoms and clusters (denoted HsGDY@Cu), a tandem catalyst of Ni-MOFs@HsGDY@Cu with dual-active interfaces was developed for the concerted catalysis of nitrate-to-ammonia. In such a system, the sandwiched HsGDY layer could serve as a bridge to connect the coordinated unsaturated Ni2+ sites with Cu single atoms/clusters in a limited range of 0 to 3.6 nm. From Ni2+ to Cu, via the hydrogen spillover process, the hydrogen radicals (H⋅) generated at the unsaturated Ni2+ sites could migrate across HsGDY to the Cu sites to participate in the transformation of *HNO3 to NH3. From Cu to Ni2+, bypassing the higher reaction energy for *HNO3 formation on the Ni2+ sites, the NO2 - detached from the Cu sites could diffuse onto the unsaturated Ni2+ sites to form NH3 as well. The combined results make this hybrid a tandem catalyst with dual active sites for the catalysis of nitrate-to-ammonia conversion with improved Faradaic efficiency at lower overpotentials.

Construction of a Schottky junction for enhanced Cr(VI) photoreduction through partial derivation of NiB from 2D Ni-MOF

Incorporating cocatalysts to form Schottky junctions offers a promising strategy for enhancing photocatalytic performance, particularly in reducing environmental pollutants. This study introduces a novel method utilizing a two-dimensional nickel-based metal-organic framework (Ni-MOF), synthesized via a solvothermal process and partially derived for the decoration of nickel boride (NiB), establishing a Schottky junction photocatalyst. The hierarchically structured Ni-MOF/NiB was synthesized under ambient air conditions with varying molar ratios of NaBH4 (0.8, 1, and 1.2) and employed for Cr(VI) photocatalytic reduction. Among these ratios, the optimal Ni-MOF/NiB-1 exhibited a remarkable photocatalytic efficiency of 96% at pH = 2 under visible light within 75 min. This enhanced performance is attributed to the formation of the Schottky junction between NiB and Ni-MOF, facilitating effective charge carrier migration and separation, as well as the high surface area, numerous active sites, improved visible light absorption, and reduced recombination rate. This effective approach of anchoring a noble metal-free cocatalyst on a porous metal−organic framework creates an economical and sustainable photocatalyst to reduce Cr(VI).

The influence of crystal facet on the catalytic performance of MOFs-derived NiO with different morphologies for the total oxidation of propane: The defect engineering dominated by solvent regulation effect

Crystal facet and defect engineering are crucial for designing heterogeneous catalysts. In this study, different solvents were utilized to generate NiO with distinct shapes (hexagonal layers, rods, and spheres) using nickel-based metal-organic frameworks (MOFs) as precursors. It was shown that the exposed crystal facets of NiO with different morphologies differed from each other. Various characterization techniques and density functional theory (DFT) calculations revealed that hexagonal-layered NiO (NiO-L) possessed excellent low-temperature reducibility and oxygen migration ability. The (111) crystal plane of NiO-L contained more lattice defects and oxygen vacancies, resulting in enhanced propane oxidation due to its highest O2 adsorption energy. Furthermore, the higher the surface active oxygen species and surface oxygen vacancy concentrations, the lower the C−H activation energy of the NiO catalyst and hence the better the catalytic activity for the oxidation of propane. Consequently, NiO-L exhibited remarkable catalytic activity and good stability for propane oxidation. This study provided a simple strategy for controlling NiO crystal facets, and demonstrated that the oxygen defects could be more easily formed on NiO(111) facets, thus would be beneficial for the activation of C−H bonds in propane. In addition, the results of this work can be extended to the other fields, such as propane oxidation to propene, fuel cells, and photocatalysis.

Synthesis and Characterization of Ni based Metal Organic Framework for Enhancing the Removal of Typical Organic Dyes

In this report we present a simple synthesis of a nickel-based metal organic framework (MOF-Ni) at the room temperature using a solution of dimethylformamide (DMF), ethanol and distilled water. The MOF-Ni synthesized in various solvents displayed numerous different properties and advantages over other materials including easy synthesis procedure, good crystallinity, rigidity, and robust chemical stability. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and thermal gravimetric analysis (TGA) were employed to analyze the as-synthesized MOF-Ni. The as-obtained MOF-Ni was used to investigate its adsorption kinetics of red telon dye (RTL) molecules. The effects of time (30–270 min), initial RTL concentration (20–300 mg/L), adsorbent dose (2–50 mg), solution pH (2–12), and temperature (10–80 °C) were investigated. The pseudo-first order rate equation was able to provide the best description of the adsorption kinetics data in the studied time scale. The Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms, and the isotherm constants were also determined. Dye adsorption turned out to strongly depend on pH, and a low pH was found to increase the amount of adsorbed dyestuff. Compared with other samples, MOF-Ni synthesized in (DMF ​+ ​C2H5OH ​+ ​H2O) had a significantly enhanced adsorption ability for RTL dye. The MOF-Ni high adsorption capacity for RTL dye was attributed to the electrostatic attraction/repulsion phenomena. Moreover, MOF-Ni showed an improved stability at 370, 417, and 423 °C temperatures. The results obtained through our experiments suggested that our porous MOF-Ni microstructures synthesized in DMF ​+ ​C2H5OH ​+ ​H2O have potential applications for treating wastewaters containing RTL dyes.