Search

In this study, an unsaturated Cu-based MOF, HKUST (Cu3(BTC)2), was fabricated and modified with sulfonate groups in two steps, leading to the construction of a novel sulfo-functionalized MOF. The prepared framework was utilized in the adsorption and separation of various organic dyes (MB, Er, FS, and MV). The adsorption process represented intriguing features due to the introduction of the SO3H functional groups into the framework. Such an attractive feature has rarely been depicted in previous works. In addition to the substantially increased adsorption capacity of the modified framework compared with that of pristine MOF, a reverse and selective phenomenon was perceived in the cases of FS and MV. The sulfo-functionalized MOF could adsorb MV with high adsorption capacity but barely adsorbed FS, and the opposite condition was observed for pristine MOF. In addition, the prepared framework showed high selectivity in a mixed solution of dyes. On the other hand, the modified framework had no role in the first step of the adsorption and separation process and showed the same behavior as pristine MOF. Furthermore, the sulfonate functional groups could not be directly incorporated into HKUST. The experimental data followed the pseudo-second-order kinetics and the Langmuir isotherm model. Thermodynamic studies demonstrated an exothermic spontaneous mechanism for the dye adsorption process. The prepared adsorbents were capable of being recycled for four sequential cycles. Hereupon, this study presents a notably efficacious approach for the reverse performance of frameworks for the dye adsorption and separation process.

Herein, we have employed a convenient method to study kinetic and thermodynamic parameters of the adsorption of molybdenum from wastewater by using modified Zr-based metal-organic frameworks, UIO-66-NH 2 -X, as adsorbents. The frameworks were fabricated with a simple and fast method from terephthalic acids and Zirconium metal ions and modified via introduction of aldehyde groups using imine condensation. This is the first report in which MOFs have been utilized as adsorbents in molybdenum adsorption. The prepared adsorbents show high adsorption efficiency which is representative of an improvement compared to other literature. The experimental adsorption data could be well interpreted with the pseudo-second-order kinetics and the Langmuir isotherm model. Thermodynamic studies illustrated an exothermic spontaneous mechanism for the adsorption process.

Metal–organic frameworks with diverse structures and unique properties have demonstrated that can be an ideal substitute for natural enzymes in colorimetric sensing platform for analyte detection in various fields such as environmental chemistry, biotechnology and clinical diagnostics, which have attracted the scientist’s attention, recently. In this study, a porous coordination network (denoted as PCN-222) was synthesized as a new biomimetic material from an iron linked tetrakis (4-carboxyphenyl) porphyrin (named as Fe-TCPP) as a heme-like ligand and Zr6 linker as a node. This catalyst shows the peroxidase and catalase activities clearly. The mechanism of peroxidase activity for PCN-222 was investigated using the spectrophotometric methods and its activity was compared with the other nanoparticles which, the results showed a higher activity than the other catalysts. Also, the hydrogen peroxide was detected by PCN-222(Fe) based on the peroxidase-like activity. For detection of hydrogen peroxide a linear range of 3–200 μM and detection of limit (LOD) 1 μM (3σ/slope), under optimal conditions were obtained. Moreover, based on the high tendency of PCN-222(Fe) to combine with the TMB as a chromogenic substrate in the peroxidase-like activity, we developed the sensitive and selective colorimetric assay for glucose detection that was found a detection limit (LOD) of 2.2 μM in the linear range from 12 to 75 μM. Finally due to the good catalytic activity of PCN-222(Fe), it was used to detection of glucose and hydrogen peroxide in real samples.

Recent years have seen an enormous growth of interest in enzyme mimics based on porous materials as a substitute for natural enzymes. This interest has been increased to a considerable extent due to the fact that they have outstanding chemical and structural features. Herein, Zr6O8(H2O)8(FeCl-tcpp)2(PCN-222(Fe)) was synthesized via a solvothermal approach with Zr6 clusters as nodes and Fe–TCPP (TCPP = tetrakis(4-carboxyphenyl)porphyrin) as a heme-like ligand and was characterized by various techniques such as XRD, TEM, SEM, XPS, UV-vis and IR. Also, since the achievement of high enzyme-like activity of some nanoparticles has attracted widespread interest in recent years, for the first time, we have applied a significant approach by modifying PCN-222(Fe) with sodium dodecyl sulfate (SDS) micelles (SDS/PCN-222(Fe)). In an attempt to explore the significance of this procedure, initially, peroxidase and catalase-like activity were investigated through a reaction with a chromogenic substrate 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS). Based on the high peroxidatic activity of SDS/PCN-222(Fe), a visual, sensitive and reliable method was established for detection of H2O2 with a linear range of 3–200 μM and limit of detection (LOD) of 2 μM. Also, as an implication of these findings, the SDS/Zr6O8(H2O)8(FeCl-tcpp)2 (SDS/PCN-222(Fe)) based system could also be used for glucose assay with a LOD of 3 μM indicating potential applications in clinical medicine. In order to prove this hypothesis, the glucose detection in human serum was determined. Finally, on the basis of SDS/PCN-222(Fe) performance, three natural antioxidants, gallic acid (GA), tannic acid (TA), and ascorbic acid (AA) were applied to explore antioxidant capabilities.

In contrast to early transition metal complexes of d0 electron configuration, their main group metal analogues are usually poor catalysts for ethylene polymerisation due to their diminished tendency to insert ethylene into an M-R bond. Interestingly, we found that ring strain in the transition structure of the insertion reaction is most likely responsible to set the ease of the process. Ethylene insertion into an M-R bond requires a four-membered ring transition structure. Strain in a four-membered ring was shown to be dependent on the metal identity (transition or main group/d or p block). For early transition metals, due to the presence of empty valence d orbitals, the strain is negligible but, for main group metals, the strain is significant and so destabilizes the corresponding transition structure. Our claim gains support from investigation of ethylene insertion into an M-allyl bond. In this case, the relevant insertion preferentially passes through a six-membered ring transition structure with an accessibly low activation barrier. In contrast to four-membered ring transition structures, six-membered ones do not suffer significantly from ring strain, causing the insertion activation barrier to become independent of the metal identity. It becomes obvious from our study that this previously undisclosed factor should play the pivotal role in determining the reactivity of many catalysts.

5-(4-Chlorobenzyl)-1H-tetrazole ligand (HL) was synthesized by Sharpless method. Furthermore, a tetrazole based Zn(II) metal organic framework, [Zn(L)2]n (1), (L = 5-(4-Chlorobenzyl)tetrazolate), was synthesized by in situ reaction of 4-chlorobenzeneacetonitrile, NaN3 and ZnCl2 under hydrothermal conditions. Both compounds are structurally characterized by elemental analysis, IR, and single crystal X-ray diffraction. Compound 1 displays undulated 2D layers, sql/Shubnikov tetragonal plane net with (44.62) point symbol. Fluorescence measurements and thermogravimetric analysis of 1 were also performed. In addition, we describe here a complex precursor, hydrothermal route to prepare ZnO nano and micro structures. The effects of reaction temperature and pH on the growth process and morphology of ZnO nano and micro structures were investigated. Finally, a possible growth mechanism is proposed. The obtained samples have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX).

(E)-4-hydroxy-3-((quinolin-8-ylimino)methyl)benzoic acid, (H2L), was synthesized and employed in the synthesis of metal complex or coordination polymers (CPs) namely, [Co(HL)2]NO3_3DMF, 1, {[Cu(L)(H2O)]_H2O}n, 2, and {[ZnL]_DMF}n, 3. Compounds have been characterized by CHN analysis, 1H NMR and IR and UV–Vis spectroscopy. Structures of 1, 2 and 3 were determined by X-ray crystallography. Compound 1 is a discrete mononuclear complex, compound 2 consists of infinite one-dimensional zig-zag chains and compound 3 displays a two-dimensional coordination polymer, uninodal shubnikov tetragonal plane network with (44_62) point symbol. Compound 3 exhibits strong fluorescence emission upon excitation at room temperature. In addition, gas sensing property of compound 3 as a thin film on one side of double sided tap on the glass substrate have also been discussed.

In this paper, regarding outstanding electrocatalytic properties of metal organic frame works for fuel cell applications, we have synthesised and investigated comprehensively the elecrocatalytic stability of PCN-222 (PCN = porous coordination network) for the oxygen reduction reaction (ORR) in acidic media. ORR is a main reaction that take parts in cathodic part of a fuel cell and preparation of a stable and efficient electrocatalyst for this reaction will effectively improve the fuel cell output. The 3D heme-like metal organic framework (MOF) was constructed from Fe(III) porphyrin linkers and Zr6 clusters.The catalyst stability tests manifested that the PCN-222 is much more stable than the other metal macrocycles. The assembled PCN-222 catalyst possesses ultra stability, high activity and excellent tolerance to the crossover effect of methanol, which could be used as a unique alternative to common ORR catalysts in an acidic direct methanol fuel cell.

A porphyrinic mesoporous metal–organic framework (PCN-222(M) (M = Mn, Fe, Cu)) has been synthesized by a simple sonochemical preparation method without high temperature in a short period of time. The ultrasonic method for the preparation of PCN-222(M) was found to be an efficient procedure with a good quantitative yield (PCN-222(M)-U). Harmful cationic and anionic dyes have been removed from wastewater using PCN-222(M). The comparative study of the influences of metalloporphyrin and non-metal porphyrin frameworks (PCN-222) on the adsorption process has been performed. Remarkably high adsorption capacity over PCN-222(M) for the anionic dyes is reported. The porphyrinic metal center of frameworks and pH values affected dye adsorption capacity, indicating the effective role of electrostatic interactions on dye adsorption. Due to the aggregation of MB and MO, a significant increase in the adsorption capacity was observed in a mixture of MB-MO solution at pH 7. High adsorption capacity over PCN-222(M) has been estimated using Langmuir and Freundlich equations. The adsorption kinetics, thermodynamic parameters, stability and reusability of adsorbents have also been reported. The stability of PCN-222(M) in water over three months was investigated (PCN-222(M)-3).

Two post-synthetic strategies have been used to prepare oxovanadium(IV) complexes covalently anchored to the organic linkers of UiO-66(NH2) (UiO = University of Oslo) metal–organic framework. In the first method, the available amino groups of UiO-66(NH2) were treated with salicylaldehyde to form the modified UiO-66 (UiO-66-SI). The synthesized UiO-66-SI was then treated with [VO(acac)2] to produce UiO-66-SI/VO(acac). In the second method, UiO-66(NH2) was directly treated with [VO(acac)2] to form UiO-66-N/VO(acac)2. The synthesized compounds were characterized by FTIR, XRD, N2 sorption, FE-SEM, TEM, EDX, ICP-AES, TGA and UV–Vis spectroscopy. The catalytic performances of UiO-66-SI/VO(acac) and UiO-66-N/VO(acac)2 were assessed in the epoxidation of geraniol with tert-butyl hydroperoxide. The results indicated 100% conversion with 100% selectivity towards 2,3-epoxygeraniol after 60 and 120 min of reaction time. These excellent catalytic activities can be attributed to the high dispersion of the catalytic sites on MOF and the proper pore size of UiO-66(NH2). Moreover, the structure of both catalysts remains intact during the catalytic reaction and the catalysts can be successfully recycled three times. High yields and excellent selectivity towards the 2,3-epoxygeraniol product, short reaction time, mild reaction conditions and recyclability of the solid catalysts are some of the advantages of these catalytic systems.

We report on the design of a bio-inspired composite as a noble-metal-free electrocatalyst for the oxygen reduction reaction (ORR). The composite is made from the assembly of pyridine- functionalized graphene (G-py) and a 3D metal–organic framework (MOF) deposited onto a glassy carbon electrode (GCE). The 3D heme-like MOF was synthesized from tetrakis(4-carboxyphenyl)porphyrin iron(III) chloride and Zr6 clusters for the assembly of the stable porous coordination network. G-py, which possesses an axial ligand to anchor to the centers of porphyrin in the MOF, results in a significant change in the electronic and geometric structure of centers, which enhances the rate of ORR and durability during cycling in acidic media. The occurrence potential of the ORR by the composite is shifted to the positive potential near 100 mV. Our results introduce a new strategy for the rational design of inexpensive and highly stable oxygen reduction electrocatalysts for fuel cells without the requirement of pyrolysis.

Nanoparticles of zirconium metal organic framework UiO-66 (about 100 nm) have been used as proper supports for Pd nanoparticles. Highly dispersed Pd nanoparticles (about 3–15 nm) were deposed on activated UiO-66 metal organic framework using simple wet impregnation method at room temperature. UiO-66 and the supported Pd nanoparticles (Pd/UiO-66) were characterized by X-ray diffraction, N2 sorption, field emission scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy and inductively coupled plasma atomic emission spectroscopy. Investigation of the catalytic performance of Pd/UiO-66 showed that the synthetic nanocomposites can effectively catalyze the Suzuki– Miyaura cross-coupling reaction of benzeneboronic acid with different aryl halides under mild reaction conditions using environmentally benign solvents. In addition, the stability and reusability of the catalyst were studied during the catalytic reaction and it is worth noting that the structure of Pd/UiO-66 catalyst remains intact during the catalytic reaction and the catalyst can be recycled four times without significant decrease in its catalytic activity.

Recent years have seen an enormous growth of interest in enzyme mimics based on porous materials as a substitute for natural enzymes. This interest has been increased to a considerable extent due to the fact that they have outstanding chemical and structural features. Herein, Zr6O8(H2O)8(FeCl-tcpp)2(PCN-222(Fe)) was synthesized via a solvothermal approach with Zr6 clusters as nodes and Fe–TCPP (TCPP ¼ tetrakis(4-carboxyphenyl) porphyrin) as a heme-like ligand and was characterized by various techniques such as XRD, TEM, SEM, XPS, UV-vis and IR. Also, since the achievement of high enzyme-like activity of some nanoparticles has attracted widespread interest in recent years, for the first time, we have applied a significant approach by modifying PCN-222(Fe) with sodium dodecyl sulfate (SDS) micelles (SDS/PCN- 222(Fe)). In an attempt to explore the significance of this procedure, initially, peroxidase and catalase-like activity were investigated through a reaction with a chromogenic substrate 2,20-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS). Based on the high peroxidatic activity of SDS/PCN-222(Fe), a visual, sensitive and reliable method was established for detection of H2O2 with a linear range of 3–200 mM and limit of detection (LOD) of 2 mM. Also, as an implication of these findings, the SDS/Zr6O8(H2O)8(FeCl-tcpp)2 (SDS/PCN-222(Fe)) based system could also be used for glucose assay with a LOD of 3 mM indicating potential applications in clinical medicine. In order to prove this hypothesis, the glucose detection in human serum was determined. Finally, on the basis of SDS/PCN-222(Fe) performance, three natural antioxidants, gallic acid (GA), tannic acid (TA), and ascorbic acid (AA) were applied to explore antioxidant capabilities.

In this study, an unsaturated Cu-based MOF, HKUST (Cu3(BTC)2), was fabricated and modified with sulfonate groups in two steps, leading to the construction of a novel sulfo-functionalized MOF. The prepared framework was utilized in the adsorption and separation of various organic dyes (MB, Er, FS, and MV). The adsorption process represented intriguing features due to the introduction of the SO3H functional groups into the framework. Such an attractive feature has rarely been depicted in previous works. In addition to the substantially increased adsorption capacity of the modified framework compared with that of pristine MOF, a reverse and selective phenomenon was perceived in the cases of FS and MV. The sulfo-functionalized MOF could adsorb MV with high adsorption capacity but barely adsorbed FS, and the opposite condition was observed for pristine MOF. In addition, the prepared framework showed high selectivity in a mixed solution of dyes. On the other hand, the modified framework had no role in the first step of the adsorption and separation process and showed the same behavior as pristine MOF. Furthermore, the sulfonate functional groups could not be directly incorporated into HKUST. The experimental data followed the pseudo-second-order kinetics and the Langmuir isotherm model. Thermodynamic studies demonstrated an exothermic spontaneous mechanism for the dye adsorption process. The prepared adsorbents were capable of being recycled for four sequential cycles. Hereupon, this study presents a notably efficacious approach for the reverse performance of frameworks for the dye adsorption and separation process.

In this study, an unsaturated Cu-based MOF, HKUST (Cu

In the present work, three “ship in a bottle” Porph@MOMs are reported as biomimetic oxidation catalysts for different reactions. These frameworks are constructed from trimesic acid and metal ions (M = Fe, Co and Mn) in which tetra(N-methyl-4-pyridyl)porphyrin (MTMPyP) is encapsulated within the cavities. Additionally, the catalytic activities of the corresponding homogeneous compounds, FeTMPyP, CoTMPyP and MnTMPyP, and the frameworks without porphyrins within the cavities were investigated in the foregoing oxidation reactions. The prepared 3D porous structures have the ability to control selectivity toward the desired product. Furthermore, they are capable of acting as effective peroxidase mimics, which successfully catalyze the oxidation of diverse olefins as well as hydrocarbons using TBHP as an oxidant. The heterogeneous catalysts significantly enhance conversion in contrast to their corresponding homogeneous systems. Remarkably, an insight into the catalyst behavior was gained from the proposed mechanism based on the reversal of selectivity. Investigation of the stability and reusability of the catalysts revealed the heterogeneity character of the catalyst with no desorption during the course of oxidation reactions. The high yields, clean reactions, high thermal stability and reusability of the catalysts make them good candidates for heterogeneous catalysts in various oxidation reactions.

We report a type of magnetic recyclable Fe3O4@SiO2@PCN-222(Fe) photocatalyst based on the Zr-porphyrin metal-organic framework (MOF) for the efficient removal of cationic (Rhodamine B (RhB)) and anionic (Erythrosine B (EryB), and Rose Bengal (RoseB)) dyes from wastewater. The synthesized MOF is an efficient visible-light-active photocatalyst for the degradation of large dyes (RhB, EryB, and RoseB). XRD, FT-IR, SEM, TGA, TEM, BET, and DRS were employed to elucidate the structural and morphological characteristics of the obtained photocatalyst. Furthermore, the conduction band of the synthesized photocatalyst was derived from the obtained Mott-Schottky plots. The photocatalytic activity of Fe3O4@SiO2@PCN-222(Fe) under visible light was higher than Fe3O4@SiO2@PCN-222(no metal), the influence of metalloporphyrin on degradation efficiency was studied and a mechanism of degradation was proposed.

In contrast to early transition metal complexes of d0 electron configuration, their main group metal analogues are usually poor catalysts for ethylene polymerisation due to their diminished tendency to insert ethylene into an M-R bond. Interestingly, we found that ring strain in the transition structure of the insertion reaction is most likely responsible to set the ease of the process. Ethylene insertion into an M-R bond requires a four-membered ring transition structure. Strain in a four-membered ring was shown to be dependent on the metal identity (transition or main group/d or p block). For early transition metals, due to the presence of empty valence d orbitals, the strain is negligible but, for main group metals, the strain is significant and so destabilizes the corresponding transition structure. Our claim gains support from investigation of ethylene insertion into an M-allyl bond. In this case, the relevant insertion preferentially passes through a six-membered ring transition structure with an accessibly low activation barrier. In contrast to four-membered ring transition structures, six-membered ones do not suffer significantly from ring strain, causing the insertion activation barrier to become independent of the metal identity. It becomes obvious from our study that this previously undisclosed factor should play the pivotal role in determining the reactivity of many catalysts.

In contrast to early transition metal complexes of d0 electron configuration, their main group metal analogues are usually poor catalysts for ethylene polymerisation due to their diminished tendency to insert ethylene into an M-R bond. Interestingly, we found that ring strain in the transition structure of the insertion reaction is most likely responsible to set the ease of the process. Ethylene insertion into an M-R bond requires a four-membered ring transition structure. Strain in a four-membered ring was shown to be dependent on the metal identity (transition or main group/d or p block). For early transition metals, due to the presence of empty valence d orbitals, the strain is negligible but, for main group metals, the strain is significant and so destabilizes the corresponding transition structure. Our claim gains support from investigation of ethylene insertion into an M-allyl bond. In this case, the relevant insertion preferentially passes through a six-membered ring transition structure with an accessibly low activation barrier. In contrast to four-membered ring transition structures, six-membered ones do not suffer significantly from ring strain, causing the insertion activation barrier to become independent of the metal identity. It becomes obvious from our study that this previously undisclosed factor should play the pivotal role in determining the reactivity of many catalysts.

In the present work, a strategy for the incorporation of nitrogen-rich units to an unsaturated Cr-based MOF, MIL-100-Cr, is reported. Based on this strategy, various cyanide functional groups (diamino malononitrile, 1,3-phenylene diacetonitrile, and malononitrile) were incorporated into the framework and utilized as exceptional catalysts in the carbon dioxide fixation under mild, solvent, and co-catalyst free conditions. This is the first report on the application of cyano-bifunctional frameworks in cycloaddition reaction. The contemporaneous presence of accessible Lewis acid sites and pendent cyanide groups results in highly striking conversion and TON even for bulky and large substrates. High tendency and strong interaction of cyanide groups with CO2 cause a synergetic effect in the performance of the catalysts. The role of different cyanide groups applied in this work has also been studied. The reaction wouldn’t proceed in the presence of pristine MOF without co-catalyst addition.

MOF-46 and a novel core-shell heterostructure containing ZnO@MOF-46 rods have been successfully synthesized via a simple, versatile and economic method. The products have been characterized by X-ray diffraction (XRD), FTIR spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX). Time and solvent effects on the growth process of ZnO@MOF-46 were investigated. Luminescent properties of the activated sample showed distinct solvent-dependent photoluminescence emissions. The product also demonstrated unique sensing properties in detection of aromatic compounds via a fluorescence quenching and enhancing mechanism. Aromatic compounds with electron-withdrawing substituents such as nitro act as fluorescence quenchers for ZnO@MOF-46 and aromatic compounds with electron-donating substituents such as CH3 were found to enhance the ZnO@MOF-46 fluorescence. The ZnO@MOF-46 showed excellent photodegradation of methylene blue. The degradation rates in presence of various scavengers including benzoquinone, isopropyl alcohol and ammonium oxalate (O2 •-, OH• and h+ scavengers, respectively) were studied and the results showed all of species (O2 •-, OH• and h+) contribute to degradation but the OH• is the main active species and plays a major role in this system and hence photocatalyst degradation was supposed to have a radical mechanism. Band structure parameters of ZnO@MOF-46 were determined using cyclic voltammetry and DRUV/VIS spectroscopy and the mechanism of photodegradation was then discussed.

Herein, we report the adoption of adjustable composition nitrogen-rich units via introduction of diverse amine groups to an unsaturated metal organic framework, MIL-100(Cr), and the application of the products obtained as novel catalysts in the aspect of CO2 cycloaddition reactions to afford cyclic carbonates in the absence of cocatalyst and solvent under mild conditions (60 °C, 1 MPa). Incorporation of amine groups to the frameworks leads to substantial increment in the catalytic performance of the structures. The concomitant presence of acidic and basic sites in the structure causes great conversion and selectivity in cycloaddition reactions even for large and bulky epoxides. The comparison of various groups of amines (2-aminopyridine, 1,2-phenylene diamine, 3- aminopyridine and ethylene diamine) incorporated on the surface with different orientations demonstrates the effect of the orientation type in catalytic activity. CO2 gas sorption measurement helps to better understand the process of catalytic activity. The pristine MOF is unable to progress the reaction without addition of co-catalyst.

The surfactant assisted hydrothermal process for selective preparation of copper nanosheets and ultralong microwires by reducing Cu2+ with 2-(bis-phosphonomethylamino)propionic acid (dpc) under the action of cetyltrimethylammonium bromide (CTAB) or polyvinyl pyrrolidine (PVP) is presented. X-ray powder diffraction (XRD) and energy dispersive X-ray analysis (EDX) indicate that the products are pure Cu of cubic phase. The effects of starting material concentration and reaction time on morphology of nanosheets have been studied by scanning electron microscopy (SEM). The presence of CTAB and PVP as capping agents is identified by EDX, transmission electron microscopy (TEM) and FT-IR. The possible growth process for ultralong microwires was studied by stopping the growth at a series of intermediate morphology stages based on SEM observations. Optical properties of Cu nanosheets and ultralong microwires were studied by UV-Vis spectrophotometry.

We report the synthesis of a composite from cobalt porphyrin-based metal organic framework (MOF) and multi-walled carbon nanotube (MWCNT), possessing good catalytic activity toward oxygen reduction (OR) and oxygen evolution (OE) processes. A 3-D porous coordination network (PCN) with 3-D nanochannels was synthesized using ultrastable Zr6 clusters and tetrakis(4-carboxyphenyl)porphyrin cobalt(II). Located in the backbone of MOF, cobalt porphyrins as the active centers are easily accessible to the reactants. The composite exhibits smaller overpotentials and higher current for OR and OE reactions compared to the commercial Pt/C catalyst. A proton-coupled electron transfer mechanism has been suggested due to the pH dependence of water oxidation on the electrocatalyst. Furthermore, the stability of the catalyst has been verified by various techniques. Our designed heterogeneous, inexpensive, and stable electrocatalyst is a proper candidate for acidic fuel cells and water splitting devices under near neutral condition without requirement of pyrolysis process.