High-temperature Carbonization Research Articles

Uncovering the Salt-Controlled Porosity Regulation in Coal-Derived Hard Carbons for Sodium Energy Storage.

Coal is a promising precursor of hard carbon (HC) anodes for sodium-ion batteries (SIBs), by virtue of resource abundance, low cost, and high product yield. However, the concomitant inorganic salt is usually recognized as impurities and plays an obscure and even contradictory effect on the regulation of pore structure in HCs. Herein, a two-step pyrolysis procedure to the representative salty coal is performed, in which the acid washing program is selectively inserted. It is illuminated that salt acts as a template or activating agent for the generation of open pores at low temperatures but inhibits the closure of pores during the following high-temperature carbonization. The optimized HC delivers a reversible capacity of 322.4 mAh g-1, a high plateau capacity of 192 mAh g-1, and an initial coulombic efficiency of 80%, outperforming to most coal-based HCs. Assembled with an NVPOF cathode, the full-cell exhibits a high energy density of 284.7 Wh kg-1. This work not only provides a systematic understanding of salt-dependent pore structure modulation but also practices a simple, cost-effective, and potentially scalable technique for the production of coal-based HCs.

Platan seeds-derived PSC/Ni/Co composite with multi-morphologies as tunable microwave absorber

Biomass and its derived carbon materials, due to their glorious application value in the field of microwave absorption, have sparked a new round of research boom. Hereinto, platan seeds-derived carbon-based materials (PSC), offspring from direct carbonization of platan seeds, were ulteriorly processed and subjected to high-temperature carbonization treatment to synthesis PSC/Ni/Co composite with diversified morphology and tunable microwave absorption performance. The effect of nickel and cobalt ion concentrations on the absorption performance of composite materials was investigated in depth. The optimum reflection loss value (RLmin) of PSC/Ni can reach −47.36 dB, while its effective absorption broadband (EAB) is 5.8 GHz, ranging from 12–17.8 GHz, covering almost the whole Ku band. Compared with PSC/Ni composites, PSC/Co fulfils greater advantages in thickness and bandwidth. As for PSC/Ni/Co, the sample exhibits the optimal performance when Ni and Co ions are at equal concentrations, with an RLmin of −48.3 dB and an EAB of 5 GHz (13–18 GHz), which congealed the edges of both. Unequivocally, the morphological polymorphism of carbon-based-derived microwave absorbing materials with platan seeds as the carbon source is crucial to harvset lightweight, efficient and adjustable absorption properties, let alone its relatively simple and feasible preparation method. This may provide a new approach for engineering light-weight, cost effective and eco-friendly absorbing materials.

High-temperature carbon dioxide capture in a porous material with terminal zinc hydride sites.

Carbon capture can mitigate point-source carbon dioxide (CO2) emissions, but hurdles remain that impede the widespread adoption of amine-based technologies. Capturing CO2 at temperatures closer to those of many industrial exhaust streams (>200°C) is of interest, although metal oxide absorbents that operate at these temperatures typically exhibit sluggish CO2 absorption kinetics and instability to cycling. Here, we report a porous metal-organic framework featuring terminal zinc hydride sites that reversibly bind CO2 at temperatures above 200°C-conditions that are unprecedented for intrinsically porous materials. Gas adsorption, structural, spectroscopic, and computational analyses elucidate the rapid, reversible nature of this transformation. Extended cycling and breakthrough analyses reveal that the material is capable of deep carbon capture at low CO2 concentrations and high temperatures relevant to postcombustion capture.

Pathways to Carbon Neutrality in Civil Engineering

Abstract. With the development of the global economy and trade exchanges worldwide, urban infrastructure and industrial development have become part of the competition among countries. However, the construction industry and the production of chemical materials emit a large amount of carbon dioxide, leading to the continuous deterioration of the environment, so it is necessary to effectively reduce emissions. As a synonym for global emission reduction, carbon neutrality plays an important role in different industries, especially in civil engineering. In this paper, we start with building materials and green construction to explore the realization of carbon neutrality at the source and center of carbon emission in civil engineering. Firstly, we introduce the low-carbon production technologies of cement and steel, including calcium recycling and membrane separation technology in the cement industry, high-temperature combustion technology and carbon capture technology in steel industry. Then, we take renewable concrete as an example to discuss the emission reduction path of green building materials. Finally, it outlines how to carry out green construction, introduces assembly carbon reduction technology and energy integration system, and demonstrates the possibility of this green construction program in the case of "T&A House".

COF-derived hierarchical porous N,O dual-doped carbon nanosheets towards efficient aqueous Zn-ion supercapacitor with long lifespan

Designing and precisely constructing novel carbon-based cathodes with a high specific surface area (SSA), excellent stability, and abundant active sites is critical for achieving high-performance zinc-ion hybrid capacitors (ZHCs). Covalent organic frameworks (COFs), a class of well-defined crystalline porous polymer materials, can integrate organic building blocks into highly ordered topological structure, offering a robust platform for specific structural design and versatile functional exploitation. In this study, hierarchical porous carbon nanosheets (PCs) with high conductivity and abundant heteroatom doping were synthesized through an in situ polycondensation reaction followed by high-temperature carbonization. This unique structure facilitates the diffusion of electrolyte ions and the adsorption/desorption of Zn2+ ions. As a result, the optimized PC-1000 electrode demonstrates a high specific capacity of 168.9 mAh g−1 at 0.1 A g−1 and remarkable stability, maintaining a high capacity retention rate of 102.5 % after more than 50,000 cycles at 10 A g−1, outperforming other PC-based materials reported in the literature. This work provides an effective way for developing carbon-based cathode materials for high-performance energy storage devices.

Photothermal evaporation of pure, saline, muddy, and dye-contaminated waters using carbon black@PDMS sponges with superhydrophilic surface

This study aimed to develop a carbon black (CB)@ polydimethylsiloxane (PDMS) sponge capable of highly efficient photothermal water evaporation. The sponge was fabricated through a straightforward method that did not entail a high-temperature carbonization process, utilizing a sugar cube as a sacrificial template to create a porous structure, followed by CB incorporation into the PDMS matrix. A polyvinyl alcohol (PVA) coating was used to enhance the hydrophilicity of the sponge, resulting in improved water absorption and distribution. The photothermal performance of the PVA-coated CB@PDMS sponge was evaluated using various contaminated water types, including seawater, muddy water, and Rhodamine-B-contaminated water. The sponge demonstrated water-evaporation rates ranging from 3.28–4.38 kg/m²·h, significantly reducing the water-evaporation enthalpy and effectively preventing salt precipitation during seawater desalination. Additionally, it maintained its performance over repeated experiments and demonstrated efficiency improvement over multiple cycles, indicating that its effectiveness increased with repeated use, likely because of surface conditioning and structural stabilization. Moreover, the water recovered from seawater, muddy water, and dye-contaminated water was free of trace contaminants, thereby yielding clean water and demonstrating the suitability of the sponge for water purification and desalination applications.

The Fabrication of ZIF-L Derived Zns/Mos2@NC Anode Materials for Remarkable Lithium-Ion Storage.

The enhancement of electrochemical performance in lithium-ion batteries can be achieved through the incorporation of MoS2 with carbon materials and various metal sulfides. In this study, a ZnS/MoS2 heterostructure was developed, featuring a two-dimensional nitrogen-doped carbon nanosheet (NC) backbone. The synthesis of ZnMoZIF-L precursors was accomplished by introducing a Mo source in a 1 : 1 molar ratio during the ZIF-L synthesis process. Following high-temperature carbonization and vulcanization treatment, ZnS/MoS2@NC composite materials were successfully synthesized. Compared to the unvulcanized ZnO/MoO3@NC and MoS2 samples, the ZnS/MoS2@NC composite exhibits remarkable lithium storage performance. At a current density of 500 mA g-1, the initial reversible capacity capacity is still as high as 1674 mAh g-1. Furthermore, this composite material demonstrates optimal rate capabilities and a significant contribution to pseudocapacitance. The nitrogen-doped carbon framework effectively mitigates volume changes, while the heterostructural design provides more active sites for lithium-ions, thereby enhancing lithium storage performance.

Technology Focus: EOR Operations (November 2024)

International agreements and national policies on environmental sustainability are changing the outlook for enhanced oil recovery (EOR) globally. These changes are highlighted by both monetary and intellectual commitments by oil companies around the world. Saudi Aramco has pledged $1.5 billion toward sustainable technology. In practice, members of Aramco’s EXPEC Advanced Research Center have collaborated with King Fahd University of Petroleum and Minerals to develop sustainable surfactants for use in high-temperature, high-pressure, and high-salinity carbonate reservoirs. They used no or only green solvents to produce soluble, stable surfactants with the potential for biodegradability. In Colombia, Ecopetrol is committed to reducing CO2 emission by 25% by 2030. As part of its efforts, it has been optimizing polymer injection in Chichimene, a heavy-oil field. By estimating life cycle greenhouse-gas emissions and energy consumption, it was able to show that polymer injection and its associated carbon intensity reduction could prevent the emission of 3,200 tons CO2 equivalent. To comply with the UK’s North Sea Transition Deal, which mandates a 50% reduction in offshore oil and gas emissions by 2030, Ithaca Energy and Energy Research Norway is using life-cycle assessment to guide more efficient heavy-oil recovery. By using low-dose polymer injection, instead of alternatives such as thermal EOR, it was able to increase exergy while also reducing CO2 emissions by 35%. In these studies, we already see the effect of the energy transition as companies turn away from traditionally effective but environmentally burdensome EOR methods such as steam injection and new polymers that show equal, if not greater, effectiveness with a reduced environmental cost. As we move forward with further regulation and innovation, it will be interesting to see how emerging technological developments in polymers, nanofluids, and even artificial intelligence can help producers meet both the economic and environmental criteria to maintain profitable fields. Recommended additional reading at OnePetro: www.onepetro.org. SPE 218653 Coinjection EOR Technology Increases Recovery and Reduces Greenhouse-Gas Emissions by G. Wasylchuk, GERI SPE 218690 Steam Generation Using Renewables Energy—An Integrated Approach for Enhanced Oil Recovery Applications by Mustafa Al Ajmi, Petroleum Development Oman, et al. SPE 218962 Reaching a Million Barrels in an Abu Dhabi Field by Focusing on Operations Efficiency by Masud J. Akhtar, Abu Dhabi National Oil Company, et al.

Experimental investigation on fracture propagation in shale fractured by high-temperature carbon dioxide

The productivity of shale reservoirs was significantly enhanced by the high-temperature CO2 fracturing technique. The injection of high-temperature CO2 into the formation induced rock fracture propagation, creating advantageous pathways for fluid flow. In this research, a self-developed in situ high-temperature convective heat simulation experimental apparatus was employed to systematically conduct simulated experiments on high-temperature CO2 fractured shale under different influencing factors. The experimental results demonstrated that the permeability of CO2 increased as the injection temperature increased. The rock fracture pressure was effectively reduced by high-temperature CO2 fractured shale. Higher complexity was observed in fracture propagation, accompanied by a substantial increase in microcracks and branching fractures. The shale fracture pressure increased with increasing triaxial stress and CO2 injection rate. The confining pressure restricted the further propagation of fractures under relatively high stress conditions, thereby reducing the width and density of fractures, lowering the fracture complexity. Nevertheless, the thermal shock effect of the fluid was exacerbated as the injection rate of high-temperature CO2 increased. The initiation of microcracks was facilitated by the intensification of local thermal stress in shale, inducing multiple curved fractures and forming a more complex fracture network. Compared to horizontal bedding shale, the fracture pressure of vertical bedding shale was relatively higher during high-temperature CO2 fracturing. In addition, the geometric morphology of fracture propagation was more complex, characterized by rougher fracture surfaces, leading to a greater improvement in reservoir reconstruction volume. This research contributed to the optimization of CO2 resource utilization, provided experimental evidence for the application of high-temperature convection fracturing technology in in situ shale conversion projects.

Visible Opacities of S-type Stars: The d 3Φ–a 3Δ Band System of ZrO

ZrO is a well-studied metal monoxide because of its astrophysical importance in characterizing S stars. The bands of the d 3Φ–a3Δ system (γ system) with v′≤4 and v″ ≤ 5 are rotationally analyzed using the PGOPHER program to provide spectroscopic constants. The high-resolution ZrO emission spectrum was recorded with a Fourier transform spectrometer using a high-temperature carbon furnace source. New ab initio calculations of the transition dipole moment were carried out in order to determine the vibronic band strengths. The spectroscopic constants, along with the band strengths, are used to calculate a line list for the γ system. This line list can be used to determine Zr abundances in S stars. We also correct the line strengths for the B 1Π–A 1Δ transition calculated in our previous work.

In situ catalyzed growth of carbon nanotube with asphalt cladding as a bicarbon synergistic framework of silicon anodes for lithium-ion batteries.

Silicon, as the most promising advanced anode material for lithium-ion batteries, faces challenges in large-scale industrial production due to the significant volume expansion effect. In this investigation, Si/CNTs/C composite materials were effectively produced through high-temperature carbonization utilizing asphalt, silicon, hexahydrate ferric chloride, and melamine as primary elements. The distinctive dual-carbon framework of asphalt-derived carbon and carbon nanotubes alleviates the volume expansion of silicon, thereby stabilizing the composite material's structure. Testing the electrochemical performance reveals that the Si/CNTs/C composite material exhibits a reversible specific capacity of 1187 mAh g-1 with a capacity retention rate of 92.6% after 150 cycles at a current density of 0.2 A g-1. Even after 500 cycles at a current density of 1 A g-1, it sustains a specific capacity of 879.4 mAh g-1 with a capacity retention rate of 87.9%, showcasing outstanding electrochemical performance.

Innovative Multielement Modification of Pitch-Derived Two-Dimensional Carbon Nanosheets as Anodes for Superior Performance Sodium-Ion Batteries.

The development of advanced anode materials for sodium-ion batteries (SIBs) using pitch-based carbon materials has the advantages of low cost, high electrical conductivity and easy structural modification. In this research, various well-established modification techniques for petroleum pitch are integrated, including the use of recrystallized NaCl as molten salt template, pretreatment and high-temperature carbonization under a pure oxygen atmosphere, and the introduction of heteroatoms (N and S) by hydrothermal methods. The resulting two-dimensional carbon nanosheets with multielement modification exhibit enhanced Na+ storage properties, thereby bringing higher cycling stability and superior rate performance. Due to its specific structure and chemical composition, NS-P-OPDC exhibited a high reversible capacity of 406.77 mAh g-1 at a current density of 100 mA g-1 and a superior rate performance of 193.20 mAh g-1 at a current density of 3 A g-1 after being applied to the anode of SIB half-cell. Especially, a capacity retention of 97.7% was still achieved after 4000 cycles. Meanwhile, the full-cell assembled by Na3V2(PO4)3 (NVP) cathode and NS-P-OPDC anode could provide a reversible capacity of 235.30 mAh g-1 at a current density of 300 mA g-1. This application proves to advance petroleum pitch-based high-performance electrodes toward greater efficiency in electrochemical energy storage.

Hierarchical MoO2@MoS2 heterojunction nanosheets anchored with metal-organic framework-derived CoFe alloy as bifunctional catalysts for flexible zinc-air batteries

Crafting a robust, high-performance, non-precious metal-based flexible air electrode is crucial for realizing flexible zinc-air batteries (ZABs). Herein, hierarchical MoO2 and MoS2 heterojunction nanosheets grown on carbon cloth (CC) are prepared through a simple hydrothermal reaction followed by calcination. Afterward, through self-assembly and high-temperature carbonization of zeolitic imidazolate framework-67 (ZIF-67) and Materials of Institute Lavoisier-101 (MIL-101) on the heterojunction nanosheets, a hierarchical structure of nitrogen-doped carbon (NC) encapsulated CoFe alloy nanoparticles (NPs) supported on MoO2@MoS2 heterojunction nanosheets (CC/MoS2@MoO2@CoFe) is obtained. It exhibits remarkable activity and durability for both bifunctional oxygen evolution and reduction reactions (OER/ORR), attributed to the ternary heterojunction formed by NC-coated CoFe alloy NPs uniformly dispersed among the MoO2@MoS2 nanosheets, along with oxygen vacancies at heterogeneous interfaces between MoS2, MoO2, and Co0.72Fe0.28 alloy. As a binder-less self-supporting electrode, the assembled aqueous ZAB demonstrates a maximum power density of 113.6 mW cm–2, surpassing that of Pt/C + RuO2 (75.2 mW cm–2), along with excellent cycling stability. Furthermore, the CC/MoS2@MoO2@CoFe-based flexible ZABs achieve a maximum power density of 54.1 mW cm–2, exhibit good cycling stability for up to 120 cycles, and show outstanding flexibility. This study paves the way for the practical integration of flexible ZABs into wearable electronic devices, heralding a new era of portable power solutions.

Interface Engineering Induced by Low Ru Doping in Ni/Co@NC Derived from Ni-ZIF-67 for Enhanced Electrocatalytic Overall Water Splitting.

Electrochemical water splitting is a promising approach for hydrogen evolution reactions (HER); however, the oxygen evolution reaction (OER) remains a major bottleneck due to its high energy requirements. High-performance electrocatalysts capable of facilitating HER, OER, and overall water splitting (OWS) are highly needed to improve OER kinetics. In this work, we synthesized a trimetallic heterostructure of Ru, Ni, and Co incorporated into N-doped carbon (denoted as Ru/Ni/Co@NC) by first synthesizing Ni/Co@NC from Ni-ZIF-67 polyhedrons via high-temperature carbonization, followed by Ru doping using the galvanic replacement method. Benefiting from increased active surface sites, modulated electronic structure, and enhanced interfacial synergistic effects, Ru/Ni/Co@NC exhibited exceptional electrocatalytic performance for both HER and OER processes. The optimized Ru/Ni/Co@NC catalyst, with a minimal Ru mass ratio of ∼2.07%, demonstrated significantly low overpotential values of 34 mV for HER and 174 mV for OER at a current density of 10 mA/cm2 with corresponding Tafel slope values of 33.42 and 34.39 mV/dec, respectively. Further, the optimized catalyst was loaded onto carbon paper and used as anode and cathode materials for alkaline water splitting. Interestingly, a low cell voltage of just 1.44 V was obtained. The enhanced electrolytic performance was further elaborated by density functional theory (DFT) calculations, which confirmed that Ru doping in Ni/Co introduced additional active sites for H*, enhancing adsorption/desorption abilities for HER (ΔGH* = -0.30 eV), lowering water dissociation barrier (ΔGb = 0.49 eV) and reducing the energy barrier for the rate-determining step of OER (O* → OOH*) to 1.62 eV in an alkaline environment. These findings reflect the significant potential of ZIF-67-based catalysts in energy conversion and storage applications.

Regulation plateau capacity and initial coulombic efficiency of furfural residues-derived hard carbon via components engineering

The scale-up application of biomass-based hard carbon (HC) in sodium-ion battery (SIB) is hampered by low initial coulombic efficiency (ICE) and specific capacity, especially for the plateau capacity. By taking advantage of furfural residues (FRs), which are mainly constructed with lignin and cellulose, a component modulation engineering strategy is adopted to prepare high performance HC. In this work, the microstructure of FR-derived HCs can be well-regulated after component modulation. Specifically, the introduction of oxygen functional groups during low-temperature oxidation process promotes the recombination of cellulose and lignin in FRs and produces more C=O in oxidized FRs, which is favorable to suppress the carbon structure from melting and rearranging during the high-temperature carbonization process, leading to a well-balanced pseudo-graphitized/disordered microstructure and excellent corresponding electrochemical performance. Experiment results reveal that the sample underwent component engineering delivers a high capacity of 302.5 mAh g−1 and excellent ICE of 90.9 %, which are higher than that of the sample direct carbonized (225.0 mAh g−1 and 75.6 %). Notably, the plateau capacity increases from 147.0 mAh g−1 to 204.2 mAh g−1, accounting for nearly 100 % of the reversible capacity increase. Our work provides a new insight of microstructure regulation of biowaste-based HC with high electrochemical performance.

Application of Y-MOF-CNT-Derived Y2O3-C@CNT Composites in Lithium-Sulfur Battery Separators.

In order to mitigate the shuttle effect of lithium polysulfides in lithium-sulfur batteries, we propose a yttrium-metal-organic framework-carbon nanotube (Y-MOF-CNT)-derived Y2O3-C@CNT composite for modifying the separator in this study. The Y-MOFs, comprising yttrium (Y) rare earth metal and terephthalic acid, exemplify a prototypical category of metal-organic framework (MOF) materials. They manifest the advantageous attributes associated with MOFs while concurrently possessing distinctive catalytic traits ascribed to rare earth elements. In this study, Y-MOF nanoparticles were synthesized on carbon nanotube (CNT) substrates via a facile aqueous solution method, succeeded by high-temperature carbonization to yield Y2O3-C@CNT composite materials. These composites were subsequently employed as coatings on one side of polyethylene (PE) separators. The resultant Y2O3-C@CNT composite inherits the particle-like morphology and porosity from its precursor Y-MOF, alongside the inherent conductivity in carbon-based materials. This amalgamation is conducive to polysulfide capture and catalytic conversion processes within lithium-sulfur batteries. The application of the Y2O3-C@CNT-coated PE separator effectively mitigated polysulfide shuttle effects and significantly enhanced the battery electrochemical performance. At a sulfur loading level of 3 mg cm-2 under a 0.5 C rate, an initial discharge specific capacity of 900 mAh g-1 was achieved. After 400 cycles, the discharge specific capacity remained at 483.85 mAh g-1 with a capacity retention rate of 53.7%. Upon increasing sulfur loading to 5 mg cm-2, the discharge specific capacity at a lower rate (0.1 C) reached 817.8 mAh g-1; even after 100 cycles, it maintained a value of 700 mAh g-1 with a capacity retention rate of 85.6%. Notably, our modified Y2O3-C@CNT separator demonstrated exceptional cycling stability, even under conditions involving high sulfur loading.

High-Yield Preparation and Properties of Phenolic Resin-Based Carbon Microspheres.

This study aims to enhance the production efficiency of carbon microspheres (CS) and expand their potential applications. To this end, resorcinol-formaldehyde microspheres (RFS) were prepared in high yield through the modified Stöber method, utilizing resorcinol and formaldehyde as carbon sources, ammonia as a catalyst, and sodium dodecyl benzenesulfonate (SDBS) as a soft template. The resulting RFS were then carbonized to obtain high yield CS. This study examined the impact of key factors, namely, the concentration of resorcinol, ammonia, and the SDBS concentration, along with the temperature of carbonization, upon the properties of the resulting CS, which were observed with regard to microscopic morphology, average particle size, homogeneity, and yield. The findings demonstrated that the proclivity of RFS to agglomerate with one another at high carbon source concentrations was markedly diminished, while the yield of CS was notably enhanced through the introduction of the anionic surfactant SDBS. The particle size of RFS can be modified within the range 200-1000 nm by adjusting the resorcinol and ammonia concentration. The prepared RFS exhibited a regular spherical morphology and a smooth surface. Furthermore, the CS displayed a uniform spherical morphology following high-temperature carbonization, with no agglomeration or cross-linking observed between adjacent particles. It was observed that the yield of RFS reached a maximum of 93.2 g/L when the resorcinol concentration was 0.7 mol/L. Following carbonization at 800 °C, the yield of CS was found to be 41.9 g/L, with a diameter of 770 nm and good monodispersity.

Removal of cefuroxime from aqueous solution by biochars derived from antibiotic mycelial residue.

In China, antibiotic mycelial residue is categorized as hazardous waste. To achieve the harmless and resourceful disposal of cephalosporin, three types of biochars from cephalosporin mycelia residues, namely non-activated carbon (BC1), ZnCl2-activated carbon (BC2), and KOH-activated carbon (BC3), were respectively fabricated by high-temperature pyrolysis carbonization technology. These three kinds of biochars were characterized via iodine value, FTIR, and SEM, and the adsorption performance of the prepared biochars was investigated using cefuroxime (CXM) as the adsorption target. The results indicated that BC3 biochar possesses the most well-developed pores and the highest iodine value of 1367.41 mg/g; The most suitable dosage is 1.6 g/L, and the lower the pH, the more favorable the adsorption effect. The investigation of adsorption kinetics revealed that it conformed to the kinetic model of pseudo-second order, as well as the process of adsorption was governed by the chemical adsorption mechanism, the rate of adsorption was affected by the collective impact of the quantity of active sites present and the interaction strength between the CXM molecules and the biochar. The exploration of adsorption thermodynamics revealed that it aligned with the Langmuir model, the surface of biochar was relatively uniform, and the adsorption was mainly of low coverage; The calculation of thermodynamic parameters demonstrated that the adsorption was exothermic and spontaneous.

Sulfur doped hollow cobalt–nitrogen–carbon oxidase-mimicking nanozyme enable sensitive chemiluminescence sensing serum total antioxidant capacity

Heteroatom doping is one of most important methodology for heightening catalytic activity of a nanozyme through modulating electronic configuration and coordinated environment of metal atoms. Here, a nitrogen/sulfur co-doped cobalt-decorated hollow carbon structure (CoS/NC) was fabricated through a simple and manageable template-assisted synthetic strategy, following high-temperature carbonization treatment. Remarkably, the CoS/NC has superior oxidase-mimicking activity than its counterparts and displays excellent catalytic action on the chemiluminescence (CL) reaction between luminol and dissolved oxygen (O2). The CoS/NC nanozyme-based CL system is highly sensitive to physiologically relevant antioxidants of both species including single electron transfer and hydrogen atom transfer. The detection limits can be reached as low as 3 nmol·L−1 ascorbic acid, 30 nmol·L−1 uric acid, 16 nmol·L−1 glutathione, and 28 nmol·L−1 cysteine. The total antioxidant capacity (TAC) of human serums has been determined in order to assess the feasibility of the CL system. The results of serum TAC, with ascorbic acid as an equivalent model, show a good consistency with those obtained by the standard CUPRAC method. This work not only benefits the rational design of a high catalytic functionality nanozyme, but also constructs a robust TAC detection platform for monitoring oxidative stress-related diseases.

Stratified nanoflower bimetallic cobalt/iron alloy derived from CoFe-MOFs as efficient peroxymonosulfate activator for antibiotics degradation: Performance, mechanism, and toxicity

Co-based metal-organic framework (Co-MOFs) derivative has gained wide attention in the field of advanced oxidative processes (AOPs). However, the degradation efficiency of single cobalt element remains suboptimal and its activation mechanism still needs to be further explored. In this study, stratified nanoflower bimetallic cobalt/iron alloys (CoFe-NC), derived from cobalt/iron bimetallic-organic frameworks (CoFe-MOFs), was synthesized via self-assembly at room temperature, hydrothermal synthesis and high-temperature carbonization processes and their performance as efficient activators of peroxymonosulfate (PMS) for the degradation of antibiotics was evaluated (removal efficiency of 100 % within 40 min, k=0.0951 min−1). The excellent degradation property benefit by specific nano-flowers structure with high specific surface area (424.67 m2/g), the cycle between Co0→Co2+↔ Co3+ and Fe0→Fe2+↔Fe3+, synergistic effect of Co and Fe bimetals. Furthermore, the CoFe-NC/PMS system exhibits exceptionally high cyclic stability (over 85 % degradation efficiency after four times degradation), a wide range of pH (3−11) and resistance to background ion interference (Cl–, H2PO4–, NO3–, HCO3– and HA), and reduced toxicity of the degradation products. Degradation mechanistic studies demonstrated that the activation of PMS by CoFe-NC generated amounts of reactive oxygen species (ROS) (SO4•−, •OH, •O2− and 1O2). Additionally, high-performance liquid chromatography-mass spectrometry (HPLC-MS) analysis identified fifteen intermediate degradation products and three possible degradation pathways were proposed. The results highlight the potential of CoFe-NC as a catalyst for antibiotic removal, providing insights into the optimization of bimetallic-organic framework for environmental applications.