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MoS2 has emerged as a highly promising catalyst for the hydrogen evolution reaction (HER) owing to its exceptional catalytic properties. However, there is a pressing need to further enhance its reactivity and integrate oxygen evolution reaction (OER) capabilities to facilitate its industrial implementation. In this context, a dual-metal doping approach presents a straightforward and effective strategy to achieve superior catalytic performance. Systematic characterization and electrochemical evaluations reveal that the synergistic effects of Co and Fe doping significantly enhance both HER and OER activities, demonstrating remarkable potential for practical applications in energy conversion and storage systems. The unique flower-like architecture of the material endows it with a substantially enlarged surface area, which significantly increases the exposure of active sites and facilitates enhanced catalytic activity. Specifically, it achieves the low overpotentials of −127 and 292 mV at 10 mA cm−2 for HER and OER in alkaline media, respectively, and demonstrates excellent stability over a 10 h test. This research provides valuable insights into the development of advanced materials capable of efficiently performing both HER and OER processes, paving the way for potential applications in sustainable energy technologies.

In the present study, an innovative electrochemical sensing platform was established for sensitive detection of NO 2 — . This sensor was developed using CoFe alloy encapsulated in nitrogen-doped carbon nanocubes (named as CoFe@NC-NCS), synthesized through the calcination of polydopamine-coated CoFe Prussian-blue analogues (CoFe-PBA@PDA). The morphological and electrochemical characterization reveals that the CoFe@NC-NCS possesses high electrocatalytic activity for electrochemical quantitation of NO 2 — , ascribed to the huge surface area and plentiful active positions, benefiting from the porous, hollow, and core–shell structure of CoFe@NC-NCS. Under the optimal conditions, CoFe@NC-NCS/GCE possessed remarkable sensing performance for NO 2 — with wide liner ranges and a detection limit of 0.015 μM. NO 2 — recovery experiments in real samples exhibited recoveries in the range of 98.8–103.5%. Hence, the CoFe@NC-NCS shows great promise for the construction of electrochemical sensor with more potential application.

HighlightsThree-dimension hierarchical core–shell Mo2N@CoFe@C/CNT composites were successfully constructed via a fast MOF-based ligand exchange strategy.Abundant magnetic CoFe nanoparticles suspended within “nanotubes on microrods” matrix exhibited strong magnetic loss capability, confirmed by off-axis electron holography.Hierarchical Mo2N@CoFe@C/CNT composites displayed remarkable microwave absorption value of − 53.5 dB.Hierarchical magnetic-dielectric composites are promising functional materials with prospective applications in microwave absorption (MA) field. Herein, a three-dimension hierarchical “nanotubes on microrods,” core–shell magnetic metal–carbon composite is rationally constructed for the first time via a fast metal–organic frameworks-based ligand exchange strategy followed by a carbonization treatment with melamine. Abundant magnetic CoFe nanoparticles are embedded within one-dimensional graphitized carbon/carbon nanotubes supported on micro-scale Mo2N rod (Mo2N@CoFe@C/CNT), constructing a special multi-dimension hierarchical MA material. Ligand exchange reaction is found to determine the formation of hierarchical magnetic-dielectric composite, which is assembled by dielectric Mo2N as core and spatially dispersed CoFe nanoparticles within C/CNTs as shell. Mo2N@CoFe@C/CNT composites exhibit superior MA performance with maximum reflection loss of − 53.5 dB at 2 mm thickness and show a broad effective absorption bandwidth of 5.0 GHz. The Mo2N@CoFe@C/CNT composites hold the following advantages: (1) hierarchical core–shell structure offers plentiful of heterojunction interfaces and triggers interfacial polarization, (2) unique electronic migration/hop paths in the graphitized C/CNTs and Mo2N rod facilitate conductive loss, (3) highly dispersed magnetic CoFe nanoparticles within “tubes on rods” matrix build multi-scale magnetic coupling network and reinforce magnetic response capability, confirmed by the off-axis electron holography.

In this study, the walnut shell (WS) supported CoFe2O4 nanopowder material (CoFe2O4/WS) were synthesized and characterized by X-ray diffraction, scanning electron microscopy, fourier transform infrared spectrometer, transmission electron microscope and X-ray photoelectron spectroscopy. The CoFe2O4/WS exhibited excellent catalytic activity in the process of activating peroxymonosulfate (PMS) to degrade ofloxacin (OFL). The results showed that 92.8% of OFL removal efficiency and 76.1% of mineralization rate were achieved at 1 g L–1 CoFe2O4/WS, 1 g L–1 PMS within 30 min. Moreover, the results of coexisting anions and organic matter indicated that the CoFe2O4/WS/PMS system has a certain anti-interference ability in complex environment. Furthermore, radical identification experiment demonstrated that SO4·− was the dominant active substance during the OFL degradation process, and a possible activation mechanism of PMS by CoFe2O4/WS was proposed. Finally, possible degradation pathways of OFL were inferred based on the reaction intermediates detected by high-performance liquid chromatography-mass spectrometry. These findings will enrich the understanding of sulfate radical-advanced oxidation process (SR-AOPs) for antibiotic wastewater treatment and will guide the development of metal-organic frameworks as catalysts for PMS.

This study innovatively employs a “dual-engineering synergy” strategy combining defect engineering and morphological engineering to construct oxygen vacancy (OV)-enriched CoFe2O4@C core–shell microreactors (OV-CFO@C) for efficient peroxymonosulfate (PMS) activation. The optimized OV-CFO@C-500 catalyst exhibits exceptional Fenton-like performance, degrading 97.65% of CIP in 12 min (kobs = 0.2984 min−1, 29.25 times that of PMS alone). Structural characterizations confirm successful OV introduction and core–shell architecture, where carbon cores prevent CoFe2O4 agglomeration while enabling reactant enrichment. Theoretical calculations reveal that core–shell structure and OV modulate d-band center positions and electron delocalization, synergistically enhancing PMS adsorption energy and electron transfer efficiency. Mechanistic studies identify cooperative radical pathways (⋅OH/SO4⋅− contribution: 54.1%) and non-radical electron transfer processes. Notably, the catalyst demonstrates strong recyclability (88.91% CIP removal after 5 cycles), broad pH tolerance (pH 3–9), low metal ion leaching (<0.06 mg L−1), and practical applicability in real water matrices. In continuous-flow degradation systems, 12 h operation achieved sustained removal rates of 96.8% for CIP and 55.2% for total organic carbon (TOC). This study provides new insights into defect-microstructure engineering for advanced oxidation process optimization. Defect-morphology dual engineering constructs OV-CoFe2O4@C core–shell microreactors with four merits: more exposed active sites, enhanced electron transfer, facilitated mass transfer and reaction kinetics, and suppressed metal leaching, achieving 97.65 % CIP removal in 12 min (kobs = 0.2984 min−1). [Display omitted] •Dual-engineering synergizes OV with core–shell microreactor to boost PMS activation.•Ov-mediated d-band modulation triggers electron redistribution of catalyst.•The carbon matrix suppresses CoFe2O4 agglomeration and enriches reactants locally.•OV-CFO@C-500 with enhanced stability and promising practical applicability.

The exploration of earth‐abundant and high‐efficiency electrocatalysts for the oxygen evolution reaction (OER) is of great significant for sustainable energy conversion and storage applications. Although spinel‐type binary transition metal oxides (AB2O4, A, B = metal) represent a class of promising candidates for water oxidation catalysis, their intrinsically inferior electrical conductivity exert remarkably negative impacts on their electrochemical performances. Herein, we demonstrates a feasible electrospinning approach to concurrently synthesize CoFe2O4 nanoparticles homogeneously embedded in 1D N‐doped carbon nanofibers (denoted as CoFe2O4@N‐CNFs). By integrating the catalytically active CoFe2O4 nanoparticles with the N‐doped carbon nanofibers, the as‐synthesized CoFe2O4@N‐CNF nanohybrid manifests superior OER performance with a low overpotential, a large current density, a small Tafel slope, and long‐term durability in alkaline solution, outperforming the single component counterparts (pure CoFe2O4 and N‐doped carbon nanofibers) and the commercial RuO2 catalyst. Impressively, the overpotential of CoFe2O4@N‐CNFs at the current density of 30.0 mA cm−2 negatively shifts 186 mV as compared with the commercial RuO2 catalyst and the current density of the CoFe2O4@N‐CNFs at 1.8 V is almost 3.4 times of that on RuO2 benchmark. The present work would open a new avenue for the exploration of cost‐effective and efficient OER electrocatalysts to substitute noble metals for various renewable energy conversion/storage applications. A simple and scalable electrospinning strategy is developed for the concurrent synthesis of CoFe2O4 nanoparticles homogeneously embedded in N‐doped carbon nanofibers (denoted as CoFe2O4@N‐CNFs). The synthesized CoFe2O4@N‐CNFs are demonstrated superior oxygen evolution reaction performance with a low overpotential, a large current density, a small Tafel slope, and long‐term durability in alkaline solution.

This study involves a novel CuO/CoFe₂O₄/MWCNTs (CCT) nanocomposite, developed by integrating cobalt ferrite (CoFe₂O₄) and copper oxide (CuO) nanoparticles onto multi-walled carbon nanotubes (MWCNTs), for the degradation of tetracycline (TC) under visible light. The photocatalyst was extensively characterized using XRD, HR-SEM, EDX, HR-TEM, UV-Vis, BET, and PL analysis. The synthesized CoFe₂O₄ and CuO nanoparticles exhibited crystallite sizes of 46.8 nm and 37.5 nm, respectively, while the CCT nanocomposite had a crystallite size of 53 nm. Microscopy confirmed a particle size of 49.2 nm for the nanocomposite, with MWCNTs measuring 15.65 nm in diameter. The band gap energy of the CCT nanocomposite was 1.6 eV, which contributed to its enhanced photocatalytic activity, as evidenced by the lower emission intensity in PL analysis. BET analysis revealed a pore volume of 0.37 cc/g and a surface area of 82.3 m²/g. Photocatalytic performance was tested across various conditions, with adjustments to nanocomposite dosages (0.1–0.5 g/L), TC concentrations (5–25 mg/L), and pH levels (2–10). Under optimized conditions (0.3 g/L CCT, 5 mg/L TC, pH 10, 120 min of visible light exposure), the CCT achieved 98.1% degradation of TC. The optimized parameters were subsequently used to assess TC degradation with individual photocatalysts: CoFe₂O₄, CuO, CT, and CCT. The enhanced photocatalytic efficiency observed can be largely attributed to the improved charge transfer dynamics and effective electron-hole separation facilitated by MWCNT doping. The reaction followed a pseudo-first-order kinetic model, with hydroxyl radicals (OH • ) identified as the key species in the degradation process. Moreover, the catalyst exhibited 96% retention of its photocatalytic efficiency after five consecutive cycles, demonstrating exceptional stability and reusability. These results emphasize the CCT composite’s potential as a highly efficient and sustainable photocatalyst for the remediation of pharmaceutical pollutants in aquatic systems.

The construction and design of highly efficient and inexpensive bifunctional oxygen electrocatalysts substitute for noble-metal-based catalysts is highly desirable for the development of rechargeable Zn-air battery (ZAB). In this work, a bifunctional oxygen electrocatalysts of based on ultrafine CoFe alloy (4-5 nm) dispersed in defects enriched hollow porous Co-N-doped carbons, made by annealing SiO 2 coated zeolitic imidazolate framework-67 (ZIF-67) encapsulated Fe ions. The hollow porous structure not only exposed the active sites inside ZIF-67, but also provided efficient charge and mass transfer. The strong synergetic coupling among high-density CoFe alloys and Co-N x sites in Co, N-doped carbon species ensures high oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) activity. First-principles simulations reveal that the synergistic promotion effect between CoFe alloy and Co-N site effectively reduced the formation energy of from O* to OH*. The optimized CoFe-Co@PNC exhibits outstanding electrocatalytic stability and activity with the overpotential of only 320 mV for OER at 10 mA·cm −2 and the half-wave potential of 0.887 V for ORR, outperforming that of most recent reported bifunctional electrocatalysts. A rechargeable ZAB constructed with CoFe-Co@PNC as the air cathode displays long-term cyclability for over 200 h and high power density (152.8 mW·cm −2 ). Flexible solid-state ZAB with our CoFe-Co@PNC as the air cathode possesses a high open circuit potential (OCP) up to 1.46 V as well as good bending flexibility. This universal structure design provides an attractive and instructive model for the application of nanomaterials derived from MOF in the field of sustainable flexible energy applications device.

Magnetic nanoparticles (MNPs) are very attractive especially for biomedical applications, among which, iron oxide nanoparticles have received substantial attention in the past decade due to the elemental composition that makes them biocompatible and degradable. However recently, other magnetic nanomaterials such as spinel ferrites that can provide improved magnetic properties such as coercivity and anisotropy without compromising on inherent advantages of iron oxide nanoparticles are being researched for better applicability of MNPs. Among various spinel ferrites, cobalt ferrite (CoFe O ) nanoparticles (NPs) are one of the most explored MNPs. Therefore, the intention of this article is to provide a comprehensive review of CoFe O NPs and their inherent properties that make them exceptional candidates, different synthesis methods that influence their properties, and applications of CoFe O NPs and their relevant applications that have been considered in biotechnology and bioengineering.

This study successfully synthesized and characterized CoFe 2 O 4 , NiFe 2 O 4 , and ZnFe 2 O 4 ferrite nanoparticles. The results showed that CoFe 2 O 4 and NiFe 2 O 4 exhibited ferrimagnetic behavior, while ZnFe 2 O 4 demonstrated antiferromagnetic properties. These magnetic characteristics influence the material’s response to electromagnetic radiation, such as visible and infrared light. Optical studies revealed that CoFe 2 O 4 had the highest radiation absorption, while ZnFe 2 O 4 showed superior reflection and transmission. The ferrites’ band gap energies, ranging from 3.3 to 3.6 eV, played a key role in their optical properties, with higher energy absorption and lower energy reflection. The refractive index varied with photon energy, reaching its peak at lower energy levels due to oxygen vacancies. Additionally, the optical conductivity increased with higher photon energy, peaking at 4.3 eV. These findings suggest promising applications in light transmission and sensing, with ferrites offering versatile optical properties that can be tailored for various uses.