Isoreticular Metal-organic Framework-3 Research Articles

Enhanced electrochemiluminescence of CdS QDs encapsulated in IRMOF-3 for sensitive detection of human epithelial protein 4

The advancement of pragmatic and highly-sensitive electrochemiluminescence (ECL) biosensors depends upon signal tags with high and stable signal intensity. Herein, enhanced ECL emission was obtained by encapsulating the dual-stabilizer-capped CdS QDs in a metal-organic framework (MOF), which served as a valid ECL signal tag for detecting biomarkers. Dual-stabilizer-capped CdS QDs reduce dangling bonds on the surface and improved the ECL emission. Furthermore, functionalized isoreticular metal-organic framework-3 (IRMOF-3) can not only load a large quantity of CdS QDs through the encapsulation capability but also serves as a co-reaction accelerator to promote the formation of more SO4•− from the S2O82−, further improving the ECL emission of QDs, while the integrated design of IRMOF-3 co-reaction accelerator and CdS QDs effectively shortens the electron transfer pathway and reduces the energy consumption in ECL system. Using human epithelial protein 4 (HE4) as the model of analysis, the biosensor demonstrated a broad linear range (50 fg mL−1∼50 ng mL−1) and a low detection limit (9.89 fg mL−1) under optimal operating conditions. The study provides an effective and alternative method to improve the ECL efficiency of QDs, significantly broadening their potential applications in sensing analysis, medical diagnostics, and bioimaging.

Isoreticular Metal-Organic Framework-3 (IRMOF-3): From Experimental Preparation, Functionalized Modification to Practical Applications.

Isoreticular metal-organic framework-3 (IRMOF-3), a porous coordination polymer, is an MOF material with the characteristics of a large specific surface area and adjustable pore size. Due to the existence of the active amino group (-NH2) on the organic ligand, IRMOF-3 has more extensive research and application potential. Herein, the main preparation methods of IRMOF-3 in existing research were compared and discussed first. Second, we classified and summarized the functionalization modification of IRMOF-3 based on different reaction mechanisms. In addition, the expanded research and progress of IRMOF-3 and their derivatives in catalysis, hydrogen storage, material adsorption and separation, carrier materials, and fluorescence detection were discussed from an application perspective. Moreover, the industrialization prospect of IRMOF-3 and the pressing problems in its practical application were analyzed and prospected. This review is expected to provide a reference for the design and application of more new nanomaterials based on IRMOF-3 to develop more advanced functional materials in industrial production and engineering applications.

Properties and release behavior of sodium alginate-based nanocomposite active films: Effects of particle size of IRMOF-3

Nanoparticles are used as fillers to improve the properties of biopolymers, and their particle size is an important parameter. This work aims to investigate the effect of particle size of isoreticular metal-organic framework-3 (IRMOF-3) on the mechanical, physical, and release properties of sodium alginate (SA)-based composite active film. In our study, IRMOF-3 with six different particle sizes was synthesized by introducing additives. IRMOF-3 loading with carvacrol (IRMOF-3/CA nanoparticles) was incorporated into the SA matrix to prepare the composite film. The characterization and testing results of films showed that the particle size of nanoparticles affected the physical morphology and chemical structure of the film. Especially smaller nanoparticles uniformly dispersed into the SA matrix more easily, forming a denser and more stable spatial network structure with SA, which could more significantly improve the tensile strength, water vapor barrier, and hydrophobic properties of the film (P < 0.05). In addition, the CA release rate from the active film could be significantly reduced by about 33.90 % even when the smallest particle size of the IRMOF-3/CA nanoparticles was added. Therefore, when IRMOF-3/CA is used as the nano-filler to develop SA-based active film, its particle size has a potential influence on the properties of the film.

Isoreticular metal-organic framework-3 post-synthetic modification: Application in a new active film based on sodium alginate and carvacrol for pork preservation

To achieve long-term effective protection of food by continuously controlling the release of active substances in an active film, IRMOF-3 was post-synthetic modified with benzoic acid (BA) to obtain BA-IRMOF-3. This modification enhanced the loading capacity of carvacrol (CA) and slowed down its release rate. Research on IRMOF-3 synthesis has found that increasing the proportion of metal nodes can improve its crystallinity. The post-synthesis modification of IRMOF-3 through amide reaction successfully enhanced the binding energy with CA from −5.1 kcal/mol to −6 kcal/mol, resulting in an improved CA loading rate of 28.62% ± 0.15% and delayed release. Furthermore, the BA-IRMOF-3/CA assembly was added to the sodium alginate matrix to prepare the active film BMC@SA, which improved the mechanical and physical properties of the film. The release and antibacterial/antioxidant properties were investigated. The results demonstrated that the active film BMC@SA exhibited significant sustained-release properties and antibacterial/antioxidant activities, reducing the growth of E. coli and S. aureus by 61.95% and 49.33% respectively. In refrigerated pork experiments, the film BMC@SA slowed down the color, weight, pH changes and inhibited microbial growth of fresh pork effectively, and extended the shelf life of pork from 6 d to 12 d, which demonstrated the potential application of active film BMC@SA in food preservation.

Synthesis of Isoreticular Metal Organic Framework-3 (IRMOF-3) Porous Nanostructure and Its Effect on Naphthalene Adsorption: Optimized by Response Surface Methodology

Naphthalene is a carcinogenic compound and its environmental release poses a major risk to human and aquatic health. Therefore, the application of nanomaterial technologies for naphthalene removal from wastewater has attracted significant attention. In this research, for the first time, the performance of IRMOF-3 for naphthalene removal from aqueous media is evaluated. IRMOF-3 with a specific surface area of 718.11 m2·g−1 has the ability to absorb naphthalene from synthetic wastewater to a high extent. The structures and morphology of IRMOF-3 were determined by FT-IR, XRD, SEM and BET analyses. Thirty adsorption experiments were conducted to obtain the best conditions for naphthalene removal. An optimum naphthalene removal efficiency of 80.96% was obtained at IRMOF-3 amounts of 0.1 g·L−1, a solution concentration of 15 mg·L−1, a contact time of 60 min and a pH = 11. The results indicate that the lower the concentration of naphthalene, the higher its dispersion at the surface of the porous nanostructure. Increasing naphthalene concentration results in its accumulation on porous nanostructures that clog cavities. In addition, high contact time provides ample opportunity for naphthalene to penetrate the cavities and pores which facilitates crystallization phenomena deep in the pores. Finally, the results of this study revealed that IRMOF-3 is one of the most effective adsorbents for naphthalene removal from wastewater.

Construction of efficient electrochemiluminescence resonance energy transfer sensor based on SnO2/SnS2QDs-Ru@IRMOF-3 composite for sensitive detection of procalcitonin.

An efficient electrochemiluminescence resonance energy transfer (ECL-RET) method is proposed which combines the luminescent materials of tris(4,4'-dicarboxylicacid-2,2'-bipyridyl) ruthenium(II) (energy donor) and tin dioxide and tin disulfide quantum dots (SnO2/SnS2QDs) (energy acceptor) into the isoreticular metal - organic framework-3 (IRMOF-3) material to form a composite. In this mode, the distance between the energy donor and the acceptor was greatly shortened, reducing the energy loss, and thereby effectively improving RET efficiency and further significantly improving the ECL signal. The obtained composite (SnO2/SnS2QDs-Ru@IRMOF-3) was combined with sandwich immunoreaction to construct an ECL immunosensor for the sensitive detection of procalcitonin (PCT). Under the optimized experimental conditions with a working potential of - 1.48V (vs Ag/AgCl), the proposed PCT biosensor exhibited a linear concentration range of 1 × 10-4-200ngmL-1, with a detection limit of 0.029pgmL-1 (S/N = 3). The biosensor was used to detect PCT in actual samples. The biosensor has broad application prospects in biological analysis and clinical diagnosis due to its high sensitivity, good selectivity, and good stability.

Development of sodium alginate-based antioxidant and antibacterial bioactive films added with IRMOF-3/Carvacrol

The purpose of this study was to compare the effects of different concentrations of the amine-functionalized isoreticular metal-organic framework-3 loaded with carvacrol (IRMOF-3/CA) on the properties of sodium alginate (SA) composite films, thus determining the optimal addition amount and further preparing bioactive packaging film with antibacterial and antioxidant activities. The morphology, structure, physical properties, antioxidant and antibacterial activities of the films were characterized and analyzed. The results showed that the thermal stability and light barrier property of the films were improved by the addition of IRMOF-3/CA. When the additional concentration was 0.4 wt%, the tensile, water vapor barrier and hydrophobic properties of the films were increased by 30.13%, 9.06% and 46.43% respectively compared with those of pure SA film. Moreover, the film added with IRMOF-3/CA had sustained antioxidant and antibacterial activities, and had an apparent fresh-keeping effect on pork, suggesting its application potential in food packaging.

Synthesis of Porous Carbon-Supported Copper-Based Electrocatalysts Derived from IRMOF: A Non-Noble Metal Electrocatalyst with Optimized Active Sites for the Oxygen Evolution Reaction

Metal-organic frameworks (MOFs) are a type of porous material that offers a highly flexible medium for future broad application due to their crystallinity, structural diversity, and permanent porosity. Herein, by doping copper with Isoreticular metal-organic framework-3 (IRMOF-3) as a precursor, an effective electrocatalyst with x%Cu/IRMOF-3 (x = 1%–10%) porous carbon spheres were prepared and characterized. The oxygen evolution reaction (OER) electrocatalytic properties of x%Cu/IRMOF-3 were investigated. According to the findings, 5%Cu/IRMOF-3–900 has a superior performance with a low overpotential of 265 mV and strong long-term stability in alkaline solution. With a porous structure and high nitrogen content, 5%Cu doped IRMOF-3 is superior to several reported precious metal-free electrocatalysts developed of MOFs. In this research, MOF has been utilized as a template to design a new approach for developing non-noble metal OER catalysts.

Dual-quenching electrochemiluminescence resonance energy transfer system from IRMOF-3 coreaction accelerator enriched nitrogen-doped GQDs to ZnO@Au for sensitive detection of procalcitonin

Herein a novel electrochemiluminescence resonance energy transfer (ECL-RET) pair of isoreticular metal organic framework-3 (IRMOF-3) enriched nitrogen-doped graphene quantum dots (N-GQDs) luminescent material (N-GQDs@IRMOF-3@N-GQDs, donor) and Au nanoparticles modified zinc oxide nanorod (ZnO@Au, acceptor) were firstly designed to fabricate a dual-quenching sandwich-type ECL immunosensor for ultrasensitive analysis of procalcitonin (PCT). IRMOF-3 not only acted as a carrier for abundantly enriching luminescent N-GQDs by internal encapsulation and external decoration, but also a coreaction accelerator which could boost the transformation of persulfate ion S2O82− to generate more anion radical SO4−, so as to promote the ECL emission of N-GQDs. Additionally, Au nanoparticles were loaded onto the ZnO nanorods through in-situ modification to obtain ZnO@Au, which was firstly applied as a dual-quencher of ECL signal. In the best test environment, a wide detection range from 0.0001 to 100 ng mL−1 was obtained and the limit of detection is 12.58 fg mL−1 (S/N = 3). With excellent reproducibility and sensitivity, the practical test consequence of PCT in human serum samples was satisfactory. These results suggested that this sensing system could provide a reference model for effective detection of disease markers in clinical medicine.

Organic-inorganic hybridization of isoreticular metal-organic framework-3 with melamine for efficiently reducing the fire risk of epoxy resin

Organic-inorganic hybrid flame retardant technology integrates independent ingredients into a whole, thus showing advantage of simultaneous improvement in flame retardant, smoke suppressant and mechanical properties of polymers over traditional flame retardants. In this work, a novel organic-inorganic hybrid flame retardant denoted as IR-MOF-3-Mel was synthesized by covalent hybridization of isoreticular metal-organic framework-3 (IR-MOF-3) with melamine. A relatively low amount of IR-MOF-3-Mel nanoparticles dramatically decreased the fire risk of epoxy resin (EP). Specifically, the EP with only 2.0 wt% of IR-MOF-3-Mel achieved a limiting oxygen index (LOI) of 30.5% as well as a UL-94 V-0 classification, whereas its counterpart with 2.0 wt% of IR-MOF-3 showed a LOI of 25.0% and no classification in UL-94 test. Furthermore, the peak heat release rate, total heat release and smoke production rate of the EP with 2.0 wt% of IR-MOF-3-Mel was declined by 74.0%, 71.4% and 35.6%, respectively, compared to neat EP. Additionally, the glass transition temperature, the tensile strength, and the young's modulus were 11 °C, 38%, and 27% higher than those of neat EP, respectively. The flame retardant mechanism analysis clarified that IR-MOF-3-Mel contributed to formation of a char layer with a high level of thermal resistance and graphitization which accounted for significantly reduced fire risks.

Nitrogen-doped carbon quantum dots conjugated isoreticular metal-organic framework-3 particles based luminescent probe for selective sensing of trinitrotoluene explosive.

Amine group-containing isoreticular metal-organic framework (IRMOF-3) particles are utilized for the first time as a trinitrotoluene (TNT) sensing material. IRMOF-3 particles are synthesized using zinc nitrate as a metal precursor and 2-amino-1,4-benzenedicarboxylic acid as a linker. The nitrogen-doped carbon quantum dots (NCQDs) are synthesized from citric acid and ethylenediamine as carbon and nitrogen precursor, respectively. The NCQDs are conjugated with IRMOF-3 particles as IRMOF-3/NCQDs. The TEM micrograph revealed the average size of IRMOF-3 particles to be 363.66nm. The photoluminescence emission intensity of IRMOF-3 particles at λem 430nm is highly increased in the presence of NCQDs (λex 330nm). Both the as-synthesized IRMOF-3 and IRMOF-3/NCQD particles are explored for TNT detection to compare the effect of NCQDs on the IRMOF-3 particle surface. Lower limit of detection (7.5 × 10-8M) and higher Stern-Volmer constant (4.46 × 106M-1) are achieved by IRMOF-3/NCQD particles. The association constant also increased from 5.3 × 104 to 2.78 × 106M-1 after the conjugation of IRMOF-3 particles with NCQDs. Moreover, enhanced selectivity for TNT over trinitrophenol is achieved using the IRMOF-3/NCQD particles. Graphical Abstract.

Novel g-C3N4 assisted metal organic frameworks derived high efficiency oxygen reduction catalyst in microbial fuel cells

The usage of efficient electrocatalyst in an appropriate way can significantly improve the oxygen reduction performance of microbial fuel cells (MFCs) cathode, which may accelerate its commercial application. In this work, isoreticular metal organic framework-3 (IRMOF-3) that modified with g-C3N4 and pyrolyzed at 850 °C (IR/CN-x%), exhibits a superior catalytic activity in alkaline electrolytes for oxygen reduction reaction (ORR). At high temperatures, after zinc evaporation, IRMOF-3 converts to a metal-free carbon skeleton that has large specific surface area. As a nitrogen source and supporting template, g-C3N4 introduces more activated nitrogen, and forms a new metal-free hierarchically porous nitrogen-doped carbon structure. As-synthesized IR/CN-50% as cathode catalyst displays a half-wave potential of 0.89 V (vs. RHE) and limit current density of 6.35 mA cm−2 in 0.1 M KOH, which is superior to commercial Pt/C (0.86 V@5.51 mA cm−2). Furthermore, IR/CN-50% shows approximately four-electron pathway and a yield of less than 4% hydrogen peroxide. Results from electrochemical tests further confirm IR/CN-50% possesses better durability and higher methanol tolerance than Pt/C. Besides, MFCs modified with IR/CN-50% present maximum power density (1402.8 mW m−3) better than the MFCs equipping with Pt/C catalyst (1292.8 mW m−3), which is a promising alternative electrocatalyst for MFCs.

Synthesis and characterization of iso-reticular metal-organic Framework-3 (IRMOF-3) for CO2/CH4 adsorption: Impact of post-synthetic aminomethyl propanol (AMP) functionalization

In this study, an iso-reticular metal-organic framework-3(IRMOF-3) exhibiting microporosity was synthesized from organic linker 2-amino terephthalic acid and salt zinc nitrate hexahydrate (Zn-(NO3)2.6H2O) via catalyst-free, solution-based direct mixing technique. Three samples of IRMOF-3 were post-synthetically functionalized with aminomethyl propanol (AMP) with three different concentrations of 25 wt%, 50 wt% and 75 wt% to produce AMP@IRMOF-3. The structural and texture properties of AMP@IRMOF-3 were studied by FESEM, FTIR, pore size distribution, powder XRD, TGA/DTG, N2 adsorption-desorption isotherms, their selective CO2/CH4 adsorption behaviour over various temperatures (298.15 K, 323.15 K, and 348.15 K). The results showed an enhancement in CO2 adsorption capacity from 1.39 mmol/g to 3.90 mmol/g due to successful incorporation of CO2 philic functionalities. Furthermore, the adsorption isotherms were studied by applying Langmuir, Freundlich, Langmuir-Freundlich, and Toth isotherm models. The isotherms study revealed the unfavourable adsorption behaviour with an increase in AMP loadings with a homogenous system.

IRMOF-3: A fluorescent nanoscale metal organic frameworks for selective sensing of glucose and Fe (III) ions without any modification

The amine functionalized isoreticular metal-organic framework-3 (IRMOF-3) is synthesized by hydrothermal method. Till now, it's widely used in the area of gas separation, adsorption, and catalysis due to large surface area, structural stability, and tunability. Here, we have reported the use of fluorescent nanoscale IRMOF-3 for highly selective detection of glucose as well as Fe3+ ions without any modification. This is due to NH2 and COOH groups are present on the surface of IRMOF-3 to bind cis-diols of the glucose molecule via host-guest interaction, and Fe3+ ions via ligand to metal charge transfer. The Synthesized IRMOF-3 has average diameter of 160 ± 20 nm and interestingly possess deep blue fluorescent emission spectra at 460 nm with quantum yield 17.3%. Using fluorometric assay, the limit of detection (LOD) of glucose and Fe3+ ions was found to be 0.56 μM and 4.2 nM respectively. More importantly, the synthesized IRMOF-3 is also utilized for detection of glucose and Fe3+ ions in bio-environmental samples.

Strong Electrochemiluminescence from MOF Accelerator Enriched Quantum Dots for Enhanced Sensing of Trace cTnI.

The development of a sensitive and practical electrochemiluminescence (ECL) bioassay relies on the use of ECL signal tags whose signal intensity is high and stable. In this work, strong ECL emission was achieved from metal organic framework (MOF) accelerator enriched quantum dots (CdTe), which were applied as an efficient ECL signal tag for trace biomarker detection. It is particularly noteworthy that a novel mechanism to drastically enhance the ECL intensity of CdTe is established because isoreticular metal organic framework-3 (IRMOF-3) with 2-amino terephthalic acid (2-NH2-BDC) as the organic ligand not only allows for loading a large amount of CdTe via the encapsulating effect and internal/external decoration but also functions as a novel coreactant accelerator for promoting the conversion of coreactant S2O82- into the sulfate radical anion (SO4•-), further boosting the ECL emission of CdTe. On the basis of the simple sandwich immunoreaction approach, cardiac troponin-I antigen (cTnI), a kind of biomarker related with myocardial infarction, was chosen as a detection model using an IRMOF-3-enriched CdTe labeled antibody as the signal probe. This immunosensor demonstrated desirable assay performance for cTnI with a wide response range from 1.1 fg mL-1 to 11 ng mL-1 and a very low detection limit (0.46 fg mL-1). This suggested that the IRMOF-3-enriched CdTe nanocomposite strategy can integrate the coreactant accelerator and luminophore to significantly enhance the ECL intensity and stability, providing a direction for promising ECL tag preparation with broad applications.

Preparation and evaluation of open-tubular capillary columns modified with metal-organic framework incorporated polymeric porous layer for liquid chromatography

An open tubular capillary liquid phase chromatographic column (1 m × 25 µm i.d.× 375 µm o.d.) was prepared by incorporating metal organic framework particles modified with vancomycin directly into zwitterionic polymer coating synthesized by the copolymerization of [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl) ammonium hydroxide and N,N'-methylenebisacrylamide. The incorporation of IRMOF-3 (isoreticular metal organic framework-3) particles improved selectivity of zwitterionic polymer coating with absolute column efficiency reaching 79900 plates for p-xylene. Besides strong hydrophilic interaction, the separation of neutral, basic, and acidic compounds demonstrates that π-π stacking interaction and the coordination effect of unsaturated Zn2+ of MOF also contribute to separation of various analytes. The RSD values (run-to-run, day-to-day, column-to-column, n = 3) of retention time of neutral compounds were less than 0.71%, 0.69% and 3.08% respectively, suggesting good repeatability. In addition, the column was applied to the analysis of the trypsin digest of bovine serum albumin, revealing the potential in separating biological samples.

Anchorage of Au3+ into Modified Isoreticular Metal\u2013Organic Framework-3 as a Heterogeneous Catalyst for the Synthesis of Propargylamines

Postsynthetic modification of metal-organic framework is a general and practical approach to access MOF-based catalysts bearing multiple active sites. The isoreticular metal–organic framework-3 (IRMOF-3) was modified with lactic acid through condensation reaction of the carboxyl group of lactic acid and amino group present in IRMOF-3 frameworks. Au3+ was subsequently anchored onto the metal–organic framework IRMOF-3 using postsynthetic modification. The synthezized IRMOF-3-LA-Au (LA = lactic acid) was characterized by powder X-ray diffraction, N2 adsorption-desorption, infrared spectroscopy, liquid-state nuclear magnetic resonance, thermogravimetric analysis, H2-temperature programmed reduction, transmission electro microscopy, and inductively coupled plasma–optical emission spectrometry. IRMOF-3-LA-Au acted as an efficient heterogeneous catalyst in the synthesis of propargylamines by three-component coupling reaction of aldehyde, alkyne, and amine. Moreover, the catalyst is applicable to various substituted substrates, including aromatic and aliphatic aldehydes, alkyl- and aryl-substituted terminal alkynes, and alicyclic amines. In addition, the catalyst can be easily separated from the mixture and can be reused for four consecutive cycles.

Study of the Active Centers and Reaction Mechanism of Fe/IRMOF-3 Derived Porous Carbons As Fe-N-C Electrocatalysts in Oxygen Reduction Reaction

By doping iron into isoreticular metal organic framework-3 (IRMOF-3) as a precursor and then annealing at 900 ºC under inert gas atmosphere, we have successfully prepared high efficient electrocatalyst of x%Fe/IRMOF-3-900 (x ranges from 1% to 10%) with porous carbon sphere structure. The electrocatalytic properties of the x%Fe/IRMOF-3-900 towards oxygen reduction reaction (ORR) are investigated by using rotating ring disk electrode (RRDE). The results demonstrate that the 1%Fe/IRMOF-3-900 exhibits the highest ORR activity: the onset and half-wave potentials are measured at 1.02 V and 0.88 V vs. RHE, respectively, together with electron transfer number of 3.90 at 0.4 V, kinetic current density of 4.5 mA cm−2 at 0.88 V, and excellent longtime stability in alkaline solution. Such high ORR activity is superior to many MOFs derived noble metal free electrocatalysts reported so far, and attributed to that the 1%Fe doped could retain the well-defined cubic morphology of the IRMOF-3, resulting in high surface area and large total pore volume, high nitrogen content and high density of electrocatalytic active N-species. The ORR active centers of the Fe-N-C catalysts and reaction mechanism also have been studied by DFT calculation and simulation. This study provides a new strategy for preparation of non-precious metal ORR catalysts using the MOF as a precursor. Figure 1

Fe/IRMOF-3 derived porous carbons as non-precious metal electrocatalysts with high activity and stability towards oxygen reduction reaction

By doping iron into isoreticular metal organic framework-3 (IRMOF-3) as a precursor and then annealing at 900°C under inert gas atmosphere, we have successfully prepared high efficient electrocatalyst of x%Fe/IRMOF-3-900 (x ranges from 1% to 10%) with porous carbon sphere structure. The electrocatalytic properties of the x%Fe/IRMOF-3-900 towards oxygen reduction reaction (ORR) are investigated by using rotating ring disk electrode (RRDE). The results demonstrate that the 1%Fe/IRMOF-3-900 exhibits the highest ORR activity: the onset and half-wave potentials are measured at 1.02V and 0.88V vs. RHE, respectively, together with electron transfer number of 3.90 at 0.4V, kinetic current density of 4.5mAcm−2 at 0.88V, and excellent longtime stability in alkaline solution. Such high ORR activity is is superior to many MOFs derived noble metal free electrocatalysts reported so far, and attributed to that the 1%Fe doped could retain the well-defined cubic morphology of the IRMOF-3, resulting in high surface area and large total pore volume, high nitrogen content and high density of electrocatalytic active N-species. This study provides a new strategy for preparation of non-precious metal ORR catalysts using the MOF as a precursor.

Metal-organic framework derived hierarchically porous nitrogen-doped carbon nanostructures as novel electrocatalyst for oxygen reduction reaction

The hierarchically porous nitrogen-doped carbon materials, derived from nitrogen-containing isoreticular metal-organic framework-3 (IRMOF-3) through direct carbonization, exhibited excellent electrocatalytic activity in alkaline solution for oxygen reduction reaction (ORR). This high activity is attributed to the presence of high percentage of quaternary and pyridinic nitrogen, the high surface area as well as good conductivity. When IRMOF-3 was carbonized at 950°C (CIRMOF-3-950), it showed four-electron reduction pathway for ORR and exhibited better stability (about 78.5% current density was maintained) than platinum/carbon (Pt/C) in the current durability test. In addition, CIRMOF-3-950 presented high selectivity to cathode reactions compared to commercial Pt/C.