MOF-derived Carbon Research Articles

Integrating V-doped CoP on Ti3C2Tx MXene-incorporated hollow carbon nanofibers as a freestanding positrode and MOF-derived carbon nanotube negatrode for flexible supercapacitors

Novel architectural electrode materials that are freestanding and exhibit improved electrochemical performances in flexible asymmetric supercapacitors are urgently needed; however, designing these materials is challenging. Herein, a Ti3C2TX MXene-aligned hollow carbon fiber (MX/HCF) is engineered and vanadium-doped cobalt phosphide nanorod arrays are grown on it (V-CoP@MX/HCF) and applied for supercapacitor positrode. V doping modulates the surface structure and electronic environment of CoP nanorods grown over conductive and flexible MX/HCFs. As expected, the optimized V-CoP@MX/HCF exhibits a better electrochemical performance (1896.8Fg−1) than that of CoP@MX/HCF and CoP@HCF. For the negative electrode, zeolitic imidazolate framework-67 (ZIF-67) grown on electrospun polyacrylonitrile (PAN) fibers is converted to cobalt nanoparticle-encapsulated nitrogen-doped carbon nanotubes at carbon nanofibers (Co-CNT@CNF) by a simple heat treatment without the burden of external catalysts and reducing gases. The as-designed freestanding Co-CNT@CNF delivers a specific capacitance of 405.5Fg−1 with superior cycling stability. A flexible asymmetric supercapacitor (V-CoP@MX/HCF//Co-CNT@CNF) is designed that unveil remarkable electrochemical properties, such as a high energy density of 72.4 Wh kg−1 at 800.12 W kg−1 and good capacitance retention (91.4 %) after 10,000 charge/discharge cycles. Furthermore, the device can maintain a consistent performance regardless of the bending degree. More importantly, this work provides new opportunities to rationally design novel freestanding cathodes and anodes for high-performance flexible asymmetric supercapacitors.

Cobalt-based MOF-derived carbon electrocatalysts with tunable architecture for enhanced oxygen evolution reaction

Development of the hydrogen economy requires the design of catalysts that increase the rate of the accompanying sluggish kinetic oxygen evolution reaction (OER). This is a key process in electrochemical energy conversion and storage, such as water splitting and metal-air batteries. The OER needs high overpotential and typically expensive precious metal-based catalysts. Therefore, designing low-cost and efficient electrocatalysts for OER is of paramount importance. In addition to focusing on the number of active sites or high specific surface area, the correlation between catalyst particle shape and performance should be considered. This work presents an electrocatalytic activity comparison of cobalt-containing carbons with different morphologies in the OER process. Employing metal–organic frameworks as carbon and metal precursors, the materials in the shape of polyhedrons, needles, unique spherical hedgehogs, and sea urchins were obtained. The effect of MOF template infiltration with additional carbon source on the physicochemical properties of electrocatalysts was also examined. The furfuryl alcohol-impregnated needle-shaped particles were characterized by a high content of cobalt active sites, surrounded by nitrogen-containing graphite layers. Electrochemical tests confirmed their best activity (overpotential 317 mV@10 mA/cm2), long stability (up to 20 h), as well as low reagents diffusion limitations (Tafel slope 57 mV/dec up to 24 mA/cm2). The vertically aligned structure of the catalyst contributed to improved detachment of the oxygen bubbles produced.

Facile synthesis of MOF-derived N doped ZnO/C nanoparticles and its adsorption activity toward dye removal

Metal–organic framework (MOF)-derived materials have gained an increasing interest and showed potential adsorption features in numerous applications. Significant attempts have been performed to boost the structure, functionality, surface area and porosity in addition to adsorption performance of MOF-derived carbon nanoparticles. Here, nitrogen-doped ZnO/carbon nanoparticles were synthesized by directly pyrolysis of Zn based metal organic framework (ZIF-8) in a nitrogen atmosphere at two different temperatures (600 and 800 °C), followed by chemical impregnation with ZnCl2 solution with ratio (10:1) wt/wt, and thermal activation at 500 °C for 1 h. SEM, TEM, XPS, nitrogen adsorption–desorption method, and TGA characterization techniques were employed to investigate the morphology and structure characteristics. Then, thorough analysis of N doped ZnO/C-(600 and 800), adsorption capacity to remove Remazol brilliant blue reactive (RBBR) dye from aqueous phase was conducted. At room temperature, the porous N doped ZnO/C with high surface area attained a maximum adsorption capacity about 49.3 mg/g and demonstrated a strong adsorption capacity toward RBBR dye. The insights of kinetic, thermodynamic and adsorption isotherm studies of the as-demonstrated samples open up more discussion for MOFs-derived carbon adsorbents for wastewater treatment.

MOF-derived N-doped carbon nanocages trap CoP nanoparticles anchored on rGO to modulate dielectric polarization behavior for microwave absorption

In order to gain a deeper insight into the effect of dielectric polarization behavior caused by defects and heterogeneous interfaces on microwave absorption capability, the structure of in situ grown cobalt phosphide in MOF-derived N-doped amorphous carbon nanocages (CoP/NC) anchored on reduced graphene oxide (rGO) sheets was used to control the number of defects and heterogeneous interfaces. The different dielectric polarization behaviors are expressed by the amplitude and range of the polarization relaxation peaks. More defects and heterogeneous interfaces not only cause more intense polarization loss, but also modulate the electromagnetic parameters to improve the impedance matching performance. The CoP/NC@rGO achieves strong absorption of −67.5 dB and absorption bandwidth of 7 GHz with only 4 wt%. First principles calculation shows the formation of interfacial dipole at the CoP-NC heterogeneous interface. This work provides a strategy for regulating microwave absorption properties by defect and heterogeneous interface-controlled polarization behavior.

The role of nitrogen-doping on the electrochemical behavior of MOF-derived carbons in ionic liquid electrolytes

Metal-organic frameworks (MOFs) derived nanoporous carbons have been intensively studied as electrode materials for electric double-layer capacitors. However, the current research on MOF-derived carbons were mainly focused on investigating electrochemical performances of supercapacitors in aqueous electrolytes, and there were only a few studies involved ionic liquids electrolytes. In addition, the research of nitrogen doping effect on MOF-derived carbons in ionic liquids electrolytes has rarely been reported. Nitrogen doping is considered to be the common and effective way to improve the electrochemical performances of carbonaceous electrodes because it can not only enhance the electrical conductivity but also bring about pseudocapacitances in aqueous electrolytes. However, the nitrogen doping effect in ionic liquids electrolytes need to be further investigated especially for MOF-derived carbons with large quantities of micropores. In this study, MOF-derived nitrogen-doped carbons were synthesized by carbonization of urea functionalized Zn-MOF-74, and their electrochemical behavior in EMIMBF4 and EMIMTFSI ionic liquid electrolytes were investigated. The nitrogen-doping degree was tuned by adjusting the amount of urea. Electrochemical test showed that nitrogen-doped carbons exhibited a maximum capacitance enhancement of 24.4 % than pristine sample in ionic liquid electrolytes. Nevertheless, nitrogen-doping contributed few pseudocapacitances in ionic liquid electrolytes, and the enhanced electrochemical performances could be ascribed to the increased electrical conductivity and the matched pore structures.

MOF-derived N-doped porous carbons activate peroxomonosulfate to efficiently degrade organic pollutants via non-radical pathways

Carbon-based heterogeneous catalysts have attracted extensive attention due to their environmentally friendly nature and the absence of metal leaching concerns. Nonetheless, enhancements in catalyst preparation and their efficacy in activating Peroxymonosulfate (PMS) to degrade organic pollutants remain areas of research. This work synthesized a novel nitrogen-doped porous carbon material (NPCs) at different temperatures using MET-6 [Zn(C2N3H2)2] Metal-organic frameworks (MOFs) precursor through a one-step pyrolysis process. The optimized NPC-900 demonstrated an elevated specific surface area and richer pore structure, validated through diverse characterization techniques. The NPC-900 was employed to activate (PMS) to degrade organic pollutants. Key catalytic active sites contributing to rhodamine B (RhB) degradation by NPC-900 were identified as graphite N and sp2 hybrid carbons, achieving 99.75 % RhB degradation. Through radical scavenging tests and electron paramagnetic resonance (EPR) spectroscopy, both free radicals (SO4−, ·OH and O2−) and non-free radicals (1O2 and electron transfer) were detected during the RhB degradation process. As the reaction progressed, non-free radicals increasingly asserted their dominant role. Employing electrospray ionization-mass spectrometry (EIS-MS) further elucidated RhB degradation intermediates, facilitating the postulation of a probable mechanism for NPC-900 activation of PMS and the subsequent RhB degradation pathway. In summary, this study introduced a metal-free catalyst capable of activating PMS through an accessible synthetic approach, offering valuable insights for the proficient degradation of organic pollutants in wastewater.

Phosphorus decorated MOF-derived microflower-like carbon as a superior anode for lithium-ion batteries

Graphite carbon for lithium-ion batteries (LIBs) has received extensive attention due to the strong stability and moderate working potential. In spite of these advantages, the intrinsic low theoretical capacity and the poor interface compatibility severely restrict the practical application of graphite carbon. Herein, a rational strategy to improve lithium storage performance of carbon derived from metal organic frameworks (MOFs) is constructively employed by decorating with red phosphorus. Because of the unique structure and properties, nickel MOFs-derived micro flower carbon matrix can not only provide more active sites for lithium storage, but also facilitate the performance of red phosphorus sites. Furthermore, the carbon decorated with red phosphorus (P/Ni@C) are tightly anchored by P-O-C bonds to provide a guarantee for the synergistic effect. The P/Ni@C anode delivers a high discharge capacity of 1184.6 mAh g−1 over 400 cycles at 200 mA g−1 and high-rate capacity of 686.8 mAh g−1 at 2000 mA g−1, which demonstrate excellent cyclic stability and charge transfer kinetics, respectively.

Correction: Development of MOF-derived zinc carbide-embedded graphitic carbon nitride as an effective nanocomposite for enhanced oxygen evolution reaction

Correction: Development of MOF-derived zinc carbide-embedded graphitic carbon nitride as an effective nanocomposite for enhanced oxygen evolution reaction

MOF-Derived Carbons Modified CdSe Quantum Dots for Photocatalytic Hydrogen Production

Metal-organic framework (MOF)-derived carbons have attracted great interest in recent years by virtue of their fascinating material properties, such as mesoporous structures, high electron conductivity and great chemical stability. By coupling the MOF-derived carbons with other functional materials, it is possible to tailor the resulting materials properties for expanding the application scenarios. Here, we have developed a low-temperature approach to the preparation of ZIF-67-derived carbon nanostructures (ZDCNT). Further coupling with CdSe quantum dots was conducted to enhance the photocatalytic performance toward solar hydrogen production. The electronic interactions between ZDCNT and CdSe were explored with time-resolved photoluminescence spectroscopy and in-situ X-ray absorption. A hydrogen production rate of 10.4 mmole g-1 hr-1 with a remarkable apparent quantum yield of 8.1 % at 300 nm can be achieved. Recycling tests further disclosed the high chemical stability for the ZDCNT modified CdSe, suggesting that the typical photocorrosion of CdSe can be resolved upon the modification with ZDCNT. This work delivers a new concept of photocatalyst paradigms by combining MOF-derived carbons with semiconductor.

MOF-derived porous carbon nanozyme-based flexible electrochemical sensing system for in situ and real-time monitoring of H2O2 released from cells

A novel flexible electrochemical sensor based on porous carbon nanosheets (PCNSs) nanozyme has been constructed for in situ and real-time monitoring of H2O2 released by cells. The PCNSs are prepared with the integration of thermal transformation, thermal activation and sonochemical exfoliation by using zeolitic imidazolate frameworks as template. The PCNSs exhibit high electrical conductivity, electrochemical activity and peroxidase-like catalytic properties, which is beneficial to H2O2 assay. With the transfer printing method, the flexible electrochemical sensor is obtained, which has excellent performances for H2O2 electrochemical detecting with wide linear range from 1 μM to 20 mM and a low detection limit of 0.76 μM. Owing to the great biocompatibility, the flexible sensor guarantees the growth of living cells for 72 h and realizes in situ and real-time monitoring the release of H2O2 from HeLa cells. The strategy of porous nanozyme preparation and flexible sensor construction provided a promising way for in situ and real-time assay of small molecules in the cellular microenvironment.

Spatial Confinement of Li Metal in Hollow Microcapsule Hosts Enabled by Heteroatom-Driven Inward Growth

In recent years, the demand for advanced batteries with high energy densities has increased significantly, along with the growing demand for electric vehicles. Li metal has garnered considerable research attention as a promising anode material because of its high theoretical specific capacity (3860 mAh g−1) and low electrochemical equilibrium potential (−3.040 V vs. standard hydrogen electrode). However, Li metal batteries still have several hurdles in their practical application because Li metal anodes experience infinite volume expansion, which induces continuous rupture and formation of solid-electrolyte interphase (SEI) layers. This leads to electrolyte consumption and corrosion of Li metal, resulting in a low Coulombic efficiency and poor cycling performance. In addition, the uncontrollable dendrite growth of Li metal may cause early battery failure and safety issues. To address these problems, extensive research efforts have been made, including artificial SEI layers, optimized electrolyte formula, and rational design of three-dimensional (3D) host materials.Among the various 3D host materials under development, carbon-based materials with hollow structures have been investigated extensively because of their attractive features. The enlarged void space (cavity) of the hollow hosts can accommodate a significant amount of Li deposits, while inhibiting volume changes during plating–stripping cycles. In addition, hollow carbon possesses much lower density than metal-based materials, thereby increasing the specific capacity and energy density. However, the lithiophobic nature of carbon combined with its high resistance to Li+ transport through nanopores on the walls significantly hinders the formation of Li deposits inside the cavity. Li may nucleate on the outer surface of the carbon particles in a nonuniform manner, thereby causing the growth of Li dendrites and electrochemically inactive Li deposits.In this study, we synthesize metal-organic framework-derived carbon microcapsules with heteroatom clusters (Zn and Ag) on the capsule walls and demonstrate that Ag-assisted nucleation of Li metal alters the outward-to-inward growth in the microcapsule host. The cavity inside the microcapsule host, which was generated by etching with tannic acid, provides large void spaces for Li metal storage. Atomic Ag clusters decorated by a galvanic displacement reaction serve as preferential nucleation sites with a reduced energy barrier and promote the inward growth of Li metal in the cavity, while suppressing nonuniform Li plating on the outer surface. Through combined electrochemical, microstructural, and simulation studies, we verify the beneficial role of Ag-assisted Li nucleation in facilitating inward growth inside the cavity of the microcapsule host, resulting in enhanced electrochemical performance. This study provides new insights into the design of reversible host materials for practical Li-metal batteries.

MOF-Derived Nitrogen-Doped Porous Carbon Polyhedrons/Carbon Nanotubes Nanocomposite for High-Performance Lithium-Sulfur Batteries.

Nanocomposites that combine porous materials and a continuous conductive skeleton as a sulfur host can improve the performance of lithium-sulfur (Li-S) batteries. Herein, carbon nanotubes (CNTs) anchoring small-size (~40 nm) N-doped porous carbon polyhedrons (S-NCPs/CNTs) are designed and synthesized via annealing the precursor of zeolitic imidazolate framework-8 grown in situ on CNTs (ZIF-8/CNTs). In the nanocomposite, the S-NCPs serve as an efficient host for immobilizing polysulfides through physical adsorption and chemical bonding, while the interleaved CNT networks offer an efficient charge transport environment. Moreover, the S-NCP/CNT composite with great features of a large specific surface area, high pore volume, and short electronic/ion diffusion depth not only demonstrates a high trapping capacity for soluble lithium polysulfides but also offers an efficient charge/mass transport environment, and an effective buffering of volume changes during charge and discharge. As a result, the Li-S batteries based on a S/S-NCP/CNT cathode deliver a high initial capacity of 1213.8 mAh g-1 at a current rate of 0.2 C and a substantial capacity of 1114.2 mAh g-1 after 100 cycles, corresponding to a high-capacity retention of 91.7%. This approach provides a practical research direction for the design of MOF-derived carbon materials in the application of high-performance Li-S batteries.

Fe-N and Fe-P dual active centers in MOF-derived carbon electrode for efficient capacitive deionization: Abundant defects and superior electrochemical properties

Carbon-based compounds play a significant role in achieving efficient capacitive deionization (CDI) desalination. However, the adsorption capacity is usually restricted by single spatial structures and limited number of ion adsorption sites. Heteroatom doping, especially multiple doping is an effective strategy to augment the surface functionalities of electrodes to improve the capacitive activity. In this work, Fe, N, P tri-doped hierarchically porous carbon (FeNPCs) were successfully fabricated via a facile one-step pyrolysis procedure. The FeNPC30 electrode demonstrated an outstanding electrosorption capacity of 40.42 mg g−1 within 15 min at 1.2 V and good cyclic regeneration capability with little decrease in charge storage during 200 charge/discharge cycles. The systematic results revealed that a reasonable ratio of Fe, N, and P yielded a synergistic effect, which not only improved the defective level and hydrophilicity, but enhanced the specific capacitance and decreased the charge transfer resistance, resulting in superior adsorption capacity and rate. The unique coordination structures of Fe-N and Fe-P modulated the charge density distribution and served as additional active sites for ions trapping, thus improving the desalination performance. This work gives deep insight into Fe-N and Fe-P dual active sites in CDI and provides a new perspective on multiple heteroatoms doped electrodes.

Synthesis of Aluminum-Based Metal-Organic Framework (MOF)-Derived Carbon Nanomaterials and Their Water Adsorption Isotherm.

The characteristics of water vapor adsorption depend on the structure, porosity, and functional groups of the material. Metal-organic framework (MOF)-derived carbon (MDC) is a novel material that exhibits a high specific area and tunable pore sizes by exploiting the stable structure and porosity of pure MOF materials. Herein, two types of aluminum-based MOFs were used as precursors to synthesize hydrophobic microporous C-MDC and micro-mesoporous A-MDC via carbonization and activation depending on the type of ligands in the precursors. C-MDC and A-MDC have different pore characteristics and exhibit distinct water adsorption properties. C-MDC with hydrophobic properties and micropores exhibited negligible water adsorption (108.54 mgg-1) at relatively low pressures (P/P0~0.3) but showed a rapid increase in water adsorption ability (475.7 mgg-1) at relative pressures of about 0.6. A comparison with the isotherm model indicated that the results were consistent with the theories, which include site filling at low relative pressure and pore filling at high relative pressure. In particular, the Do-Do model specialized for type 5 showed excellent agreement.

Recent progress and perspectives of metal organic frameworks (MOFs) for the detection of food contaminants

Over the past decades, increasing research in metal-organic frameworks (MOFs) being a large family of highly tunable porous materials with intrinsic physical properties, show propitious results for a wide range of applications in adsorption, separation, electrocatalysis, and electrochemical sensors. MOFs have received substantial attention in electrochemical sensors owing to their large surface area, active metal sites, high chemical and thermal stability, and tunable structure with adjustable pore diameters. Benefiting from the superior properties, MOFs and MOF-derived carbon materials act as promising electrode material for the detection of food contaminants. Although several reviews have been reported based on MOF and its nanocomposites for the detection of food contaminants using various analytical methods such as spectrometric, chromatographic, and capillary electrophoresis. But there no significant review has been devoted to MOF/and its derived carbon-based electrodes using electrochemical detection of food contaminants. Here we review and classify MOF-based electrodes over the period between 2017 and 2022, concerning synthetic procedures, electrode fabrication process, and the possible mechanism for detection of the food contaminants which include: heavy metals, antibiotics, mycotoxins, and pesticide residues. The merits and demerits of MOF as electrode material and the need for the fabrication of MOF and its composites/derivatives for the determination of food contaminants are discussed in detail. At last, the current opportunities, key challenges, and prospects in MOF for the development of smart sensing devices for future research in this field are envisioned.

Fe-MOF-derived carbon compounds as catalysts for trichloroethylene degradation via persulfate oxidation: Role of precursor template and pyrolysis temperature

Trichloroethylene (TCE) commonly exists in contaminated water as a persistent toxic pollutant. The advanced oxidation of persulfate (PS) is a promising method for degrading organic pollutants. Heterogeneous Fe-carbon composites prepared by pyrolysis with metal–organic frameworks (MOFs) have attracted attention. However, the intrinsic relationship between the physicochemical properties and catalytic performance of MOF-derived carbon compounds via PS is unclear. This study investigates TCE removal by Fe-MOF-derived carbon (MFC) with PS. The effects of the precursor template structure, pyrolysis temperature, and coexisting substances on TCE removal over the MFC/PS system are examined. Fe-MOF-derived from different precursor templates presented different TCE removal rates of 75.2–85.0%. The pyrolysis temperature of MFC alters the pore size, phase composition, and other properties, thereby affecting electron transport in the materials and catalyzing the degradation process. The total TCE removal reached 85.8% with MFC600, derived from MF88B and pyrolyzed at 600 ℃. This catalyst demonstrated excellent performance for PS degradation over a wide pH range (3−9). Moreover, free-radical and nonradical pathways coexist in the MFC600/PS system. During the TCE degradation process, oxygen vacancies, Fe species (Fe0, Fe3N, Fe3C, and Fe3O4), and N species (pyridinic N and graphitic N) were active centers in the material and played a major role in catalytic degradation. They participated in the subsequent generation of HO•, SO4•-, and •O2-, and 1O2. Furthermore, a possible degradation mechanism is proposed. This study elucidates the control of the physicochemical properties of carbon-based catalysts by exploiting MOF diversity.

Metal-free N-doped spongy carbon recycled from waste MOF for enhanced catalytic ozonation: Mechanistic insights and practical applications

At present, considerable efforts have been devoted to the development and application of MOFs, and some MOFs have realized industrial mass production and sales. However, little attention was paid to the treatment and disposal of the resulting waste MOF. In this study, the antibiotic(N source)-saturated waste MOF adsorbent was recycled into metal-free N-doped carbocatalyst through one-step pyrolysis. Compared with the pristine MOF-derived undoped carbon, N-doping led to nearly 2-fold enhancement in the pseudo-first-order rate constant for catalytic ozonation of oxalic acid (OA), and the COD removal of coking and swine wastewaters reached more than 60 % within 30 min. Apart from the formation of spongy porous morphology and the boosting of specific surface area from 253.7 to 320.6 m2/g after N doping, the characterization analysis and OA degradation results revealed that oxygen vacancies, hydroxyl groups and N species were the main active sites. Furthermore, it was identified the dominant contribution of OH in OA destruction, followed by O2— and 1O2, and the metal-free N-doped carbon displayed good reusability and chemical stability. This study proposes a feasible strategy for the utilization of waste MOF, showing great reference significance for the expansion of material functions.

In-situ embedded ultrafine Bi12O17Br2 nanotubes in MOF-derived hierarchical porous carbon for enhanced photocatalytic CO2 conversion to CO

Increasing the utilization efficiency of photogenerated electrons is highly recognized as one of the efficient approaches to boost the photocatalytic CO2 conversion efficiency. Herein, ZIF-67-derived porous carbon (PC) material was employed for the construction of PC@ultrafine Bi12O17Br2 nanotubes (PC@BOB NTs) composites through a facile solvothermal synthesis in order to optimize the use of excited electrons in the BOB NTs. Photoelectrochemical characterization results revealed that the introduction of PC material achieved a faster charge separation rate in the PC@BOB composites, ensuring more photogenerated electrons participate in the CO2 adsorption and activation process. Moreover, the pore structures of ZIF-67-derived PC material provided abundant confined spaces for the enrichment of CO2 molecules. After 5 h of Xenon lamp irradiation, PC@BOB composites exhibited obviously increased photocatalytic CO2 reduction activity in the pure water. When the addition amount of PC was 5 wt%, the PC@BOB-2 composite showed the highest CO evolution rate of 359.70 µmol/g, which was 2.95 times higher than that of the pure BOB NTs. This work provides some independent insights into the applications of Metal-Organic Framework (MOF)-derived hierarchical porous structures to strengthen the CO2 enrichment, as well as the excited charge utilization efficiency, thus achieving a high solar-to-fuel conversion efficiency.

MOF-derived FeCo carbon nanomaterials with abundant oxygen vacancies as highly efficient peroxymonosulfate catalyst for ciprofloxacin degradation

In this work, the FeCo-NB@C catalysts were prepared via calcination with FeCo-MOF as a precursor for highly efficient activation of peroxymonosulfate (PMS). SEM and XPS indicated that FeCo-NB@C possesses mass metal active sites and abundant oxygen vacancies. A synergistic effect (synergy indices 4.6) was observed in the FeCo-NB@C600/PMS process. The ciprofloxacin (CIP) could be almost degraded completely within 15 min in the optimal conditions. It was noted that FeCo-NB@C600/PMS process still performed well on CIP removal under multiple inorganic anions and real water matrix conditions. Radical quenching experiments, EPR analysis, and contribution calculation identified that SO4•−, •OH, and other ROS (O2•− and 1O2) played dominant role in CIP degradation, accounting for 60.24%, 20.19%, and 17.46%, respectively. The redox cycle of Co2+/Co3+ and Fe2+/Fe3+ induced the production of SO4•− and further formed •OH, etc. In addition, the formation of O2•− was confirmed by the role of oxygen vacancies rather than O2 through a series of designed experiments. Furthermore, the characterization results illustrated that FeCo-NB@C600 was largely unchanged with low ion leaching after three times cycles in PMS activated process, indicating the excellent stability and reusability of FeCo-NB@C600. Finally, the results of CIP degradation pathways and toxic evaluation revealed the low ecotoxicity of the intermediate products. This study demonstrates the synergistic catalytic mechanism of bimetallic catalysts in the persulfate activation, promising to realize sustainable and efficient water treatment technology.

Metal-organic framework-derived brain platygyra coral-like porous carbon architectures for real-time monitoring of hydrogen peroxide in biological matrices

The rational design for controlling the morphology and heteroatom doping of MOF-derived carbons (MCs) is one of the challenges for their electrochemical applications. In this work, brain platygyra coral-like porous carbon architectures with uniform N atom doping have been firstly fabricated by direct carbonization of schistose MIL-101-NH2 and simple acid etching. Due to the uniquely superficial sulci and gyri distribution, hierarchical pore structures with mesopore-connected micropores, and the functionality with uniform N atom doping and oxygen-containing functional groups, the resultant porous carbon as a novel metal-free electrocatalyst afforded high performance for H2O2 reduction with a low detection limit of 0.13 μM and a wide linear detection range of 1.0–26000.0 μM. Significantly, real-time monitoring of H2O2 from living cells upon stimulation as well as detection of H2O2 in serum samples were achieved. This work not only provides a facile strategy to accurately control the morphology and heteroatom doping of MCs, but also opens up a new avenue for the development of metal-free biosensors for H2O2 real-time sensing.