Fe3O4 Layer Research Articles

Optically Readable Multilevel Magnetic Memory States in Perpendicularly Exchange-Biased Ferromagnetic Multilayers.

The construction of multilevel magnetic states using materials with perpendicular magnetic anisotropy (PMA) offers a novel approach to enhancing the storage density and read/write efficiency of nonvolatile magnetic memory devices. In this study, optically readable multilevel magnetic domain states are achieved by inducing asymmetric interlayer interactions and decoupling the magnetic reversal behavior of individual ferromagnetic (FM) layers in exchange-biased FM multilayers with PMA. Hepta-level magnetic domain states are formed in [Co/Pt]n FM multilayers grown on an antiferromagnetic Fe2O3 layer within a relatively low magnetic field range of ∼±400Oe. Raising and lowering operations between states are demonstrated to be achievable, enabling the writing of new information without the need for initialization in multilevel magnetic memory applications. This design concept, leveraging multilevel magnetic domain states and facilitating noncontact optical reading of stored information, demonstrates the potential to enhance the storage density of nonvolatile magnetic memory devices as it eliminates the need for electrical circuits typically required in other resistive memory technologies.

Research on the tribological properties of kaolin/MoDDP composite lubricant additives under heavy load and impact conditions

PurposeWith respect to severe working conditions such as heavy load and impact, this paper aims to investigate the friction reduction and anti-wear performance of kaolin and molybdenum dialkyl dithiophosphate (MoDDP) composite lubricant additives to improve the lubrication effect of a single additive.Design/methodology/approachA four-ball friction test was carried out to determine the optimal concentration of kaolin and organic molybdenum additives and the tribological properties of the kaolin/MoDDP composite lubricant additives. A ring block test of composite lubricant additives was designed to investigate its lubrication performance under the severe working conditions of low speed, heavy load and impact.FindingsThe results showed that the optimal addition mass fractions of kaolin and MoDDP were 4.0 and 1.5 Wt.%, respectively, when kaolin and MoDDP were used as single lubricant additives. Compared with the single additive, the 4.0 Wt.% kaolin/1.5 Wt.% MoDDP composite lubricant additive showed excellent friction reduction and anti-wear effects under heavy load and impact conditions. Physicochemical analysis of the wear surface revealed that the lamellar kaolin additive and MoDDP had excellent synergistic effects, and the friction process promoted the generation of lubricant films containing a chemically reactive layer of MoS2, MoO2, FeS2 and Fe2O3 and a physically adsorbent layer containing SiO2 and Al2O3, which play important roles in anti-wear and friction reduction.Originality/valueThe excellent friction reduction and anti-wear effects of lamellar silicate minerals and the excellent antioxidant properties and good synergistic effects of molybdenum were comprehensively used to develop the composite additives with great lubricating properties.

Zero Valent Iron/Ni (FeNi) bimetallic heterostructure for scalable fabrication of polyvinylidene fluoride/FeNi films and efficient organic contaminant removal under UV/persulfate system

Surface heterogeneity on nano zero-valent iron (nZVI) with an additional metal is expected to enhance the catalytic performance and stability by inhibiting metal corrosion and leaching. The influence of passivation by Ni/NiO on the stability of nZVI is examined through degradation performance of uniformly aged nZVI and nZVI/Ni (FeNi) samples via photo-Fenton like reactions under UV/potassium persulfate (PS) system. FeNi bimetallic nanoparticles (BNPs) exhibits enhanced degradation than bare nZVI as thin layers of Fe3O4 and NiO which contribute towards photocatalytic degradation and anticorrosive effects by nickel inclusion. FeNi BNPs achieve 98 % degradation for pharmaceutical antibiotic levofloxacin (LEVO) within 120 min and 93 % degradation for Methylene Blue dye (MB) within 60 min, outperforming nZVI. To overcome secondary pollution, a stable polyvinylidene fluoride (PVDF)/FeNi film was fabricated to treat the contaminated water. The free-floating PVDF/FeNi film achieved 95 % degradation of MB and 98.3 % degradation of LEVO, maintaining a degradation efficiency of 95.9 % after five successive cycles. FeNi BNPs are also immobilized in the dialysis membrane resulting in 99.9 % and 99 % removal of MB and LEVO respectively. MB degradation using PVDF/FeNi film is validated through the micro reactor model developed in COMSOL Multiphysics. The parameters determined from the Langmuir-Hinshelwood (L-H) kinetic model include an intrinsic rate constant of 2.18 ×10−6 mol m−3 min−1 and an adsorption constant of 1.43 ×1019 m3 mol−1. This work introduces a cost-effective and scalable technique for the efficient remediation of contaminants in wastewater.

Preparation of CIP@Fe3O4 particles and their impact on the fenton reaction processing performance of single-crystal SiC

This study proposes the preparation of CIP@Fe3O4 composite magnetic particles, which maintain excellent magnetic properties while exhibiting superior Fenton reaction performance for the magnetorheological chemical polishing of single-crystal SiC. The CIP@Fe3O4 particles were prepared by coating a nanoscale layer of Fe3O4 onto micron-sized carbonyl iron powder (CIP) using the co-precipitation method. Their Fenton reaction performance and magnetic properties were characterized, and CIP@Fe3O4 was used as a solid-phase catalyst in Fenton reaction-induced etching, frictional wear, and polishing experiments on single-crystal SiC. The prepared CIP@Fe3O4 particles have a saturation magnetization of 184.3 emu/g, representing only an 8.7 % reduction compared to CIP, yet achieved a decolorization rate of 76.2 % for the methyl orange indicator (compared to only 17.2 % with CIP alone). The Fenton reaction using CIP@Fe3O4 resulted in a prominent corrosion layer on the surface of single-crystal SiC, with the oxygen atomic fraction reaching 22.15 %. The study examined material removal from SiC under Fenton reactions with different solid-phase catalysts: CIP, CIP@Fe3O4, and CIP + Fe3O4. Frictional wear results indicated that the maximum scratch cross-sectional removal area on the SiC surface under the Fenton reaction with CIP@Fe3O4 was 474.38 μm2, representing a 207.3 % increase compared to without the Fenton reaction. Additionally, Si-O compounds were identified in the debris. Polishing experiments showed that the material removal rate (MRR) with the Fenton reaction was 3295 nm/h, an increase of 220.2 % compared to without the Fenton reaction, and the surface roughness was reduced to Ra 0.895 nm, a 73.4 % reduction compared to without the Fenton reaction. This study provides additional evidence for the application of magnetorheological technology and the Fenton reaction in the polishing field of single-crystal SiC.

Effect of post-oxidation times in the nitrocarburizing process on the wear behavior of an AISI 4140 steel

Abstract This study investigates the influence of post-oxidation duration on the wear performance and microstructural features of AISI 4140 steel subjected to nitrocarburizing followed by post-oxidation. For this aim, the quenched and tempered AISI 4140 samples were nitrocarburized (NC) and post-oxidized (PO) at various times (45–180 min) under low vacuum. Microstructural features were investigated using optical microscopy, scanning electron microscope (SEM), energy-dispersive X-ray spectrum analysis (EDS), X-ray diffraction (XRD) analysis, and microhardness test. Wear behavior was evaluated using a ball-on-disk tribometer. Experimental results showed that the structures consisting of nitride layer (ε-Fe2–3N) and γ′-Fe4N + iron oxide (Fe3O4) were obtained at the top surfaces of the samples. Increasing post-oxidation times resulted in a notable enhancement in the thickness of the Fe3O4 layer. The growing Fe3O4 layer has induced the closing of micro porosities for further post-oxidizing times, leading to decreased surface roughness of the samples. It was determined that the post-oxidation times have no significant effect on the hardness profiles of NC + PO samples. The highest (0.375) and lowest (0.276) mean coefficient of friction was obtained in the post-oxidation times of 150 and 180 min, respectively. The best wear rate was obtained in the post-oxidized sample for 150 min.

Ultra-Sensitive and Selective Surface Plasmon Resonance using Ag Metal, Carbon Nanotube, and Selenium Based Biosensors for the Detection of Ascorbic Acid

In this work, we present a novel surface plasmon resonance (SPR) sensor for ascorbic acid detection based on a borosilicate crown (BK7) prism coated with a multilayer structure made of ferric oxide (Fe2O3), silver (Ag), and carbon nanotube (CNT). The SPR sensor improves sensitivity and selectivity for ascorbic acid detection by taking advantage of the special optical characteristics of the multilayer construction. The CNT layer offers increased surface area and biocompatibility, and the Ag layer acts as a plasmonic material to promote surface plasmons. The performance of the sensor is improved by the addition of selenium (Se) and Fe2O3 layers, which provide further capabilities like photoconductivity and magnetic manipulation, respectively. Numerical analysis at the operating wavelength of 633 nm is conducted using the transfer matrix approach. For the proposed SPR sensor at room temperature, the performance characteristics, including sensitivity (274.37 degree (°)/RIU), figure of merit (40.60 RIU−1), and detection accuracy (0.189°−1), are computed. The proposed SPR sensor could be very useful in to detect ascorbic acid in the visible range.

Photocatalytic activities of Fe2O3 coated ZnO nanowires grown by electrochemical anodization method

In this study, the visible light photocatalytic activities of the ZnO and ZnO/Fe2O3 structures were investigated. Anodization of Zn plates to obtain ZnO nanowires was carried out by applying 35 V between 1 and 30 min durations. Fe2O3 layers were coated on initially obtained ZnO nanowires through a sol-gel spin-coating process. All samples were examined for morphological, structural, optical, and photocatalytic activities in detail. The results showed that the conducted anodization process was successful where up to micrometer-length nanowires were obtained. SEM images confirmed the presence of Fe2O3 deposits surrounding the nanowires, while UV and visible absorption spectra indicated increased absorption due to Fe2O3, leading to enhanced photocatalytic performance. The best-performing ZnO nanowire anodized for 5 min almost doubled its photocatalytic activity after Fe2O3 coating, in which an apparent reaction rate of 12.24 × 10−3 min−1 and degrading 90.32 % of the initial MB concentration was recorded.

Comparison of diffusion coatings resistance on ferritic and austenitic-stainless steels at 650 °C in steam oxidation

Iron-aluminide coatings were deposited on T24, P92 and Incoloy 800HT (IN-800HT) by pack-cementation and by a water-based slurry. According to the differences in heat treatments between the two processes, Al-rich phases, i.e. Fe4Al13 and Fe2Al5 were obtained by pack cementation and only B2-(Fe, Ni)Al by slurry. Vertical or horizontal cracks were present on certain coatings, the former being due to the coefficient of thermal expansion (CTE) mismatch with the substrate while the latter were related to the brittleness of the Al-rich phases. The oxidation behaviour of uncoated and coated substrates was studied at 650 °C up to 1000 h under a low steam flow rate (1.07 × 10−5 m/s). The aluminide coatings were very protective on the low Cr substrates (i.e. T24 and P92) because of the formation of a very thin oxide scale compared to the non-protective thick layers of Fe3O4 and Fe2O3 that grew on both uncoated substrates. In contrast, none of the coatings significantly improved the oxidation resistance of the IN-800HT steel despite the growth of a thin oxide layer made of (Fe, Cr)2O3 and (Fe, Cr)3O4 at 650 °C.

The static corrosion behaviors of gelcasted MAX phases in contaminated lead-bismuth eutectic (LBE) at 600 °C with low oxygen

The deployment of gelcasted MAX phase ceramic components in nuclear reactors is critical due to their exceptional performance. This study explores the corrosion behaviors of three gelcasted MAX phase ceramics (Ti3AlC2, Ti2AlC, and Ti3SiC2) in liquid lead-bismuth eutectic (LBE) at 600 °C under low oxygen conditions. Unique corrosion layers formed on the samples: Ti₃AlC₂ developed an Al2O3 inner layer and TiO2 outer layer, Ti₂AlC showed TiO2 grains coated with FeCr2O4 spinel, and Ti3SiC2 exhibited a composite layer of TiO2, Fe3O4, SiO2, PbO, and TiO2. LBE caused slight matrix enrichment in Ti₃AlC₂ and Ti₂AlC samples. Corrosion resistance was ranked as Ti3SiC2 > Ti3AlC2 > Ti₂AlC. Additionally, a coupled corrosion phenomenon resembling electrolytic electrodeposition between MAX phase ceramics and stainless steel was observed in contaminated LBE. This research provides novel insights into the corrosion mechanisms of MAX phases, paving the way for their application in advanced nuclear systems.

Study on the Corrosion Behavior of inconel 625 deposited metal against molten nitrate

In order to investigate the corrosion resistance of Inconel 625 deposited metal under two conditions of isothermal and thermal cycling in nitrate molten salt, this paper conducted nitrate molten salt tests on its alloy at alternating temperatures between 565 ℃ and 290 ℃-565 ℃. By using SEM, XPS and other methods to characterize the corroded samples, it was found that the corrosion amount of the deposited metal under isothermal conditions was higher than that under thermal cycling conditions. The results showed that compared to corrosion under isothermal conditions, the corrosion weight loss of Inconel 625 deposited metal under thermal cycling conditions was 0.536×10−3 mg/mm2, 0.714×10−3 mg/mm2, 0.1429×10−2 mg/mm2, and 0.232×10−2 mg/mm2, respectively, which were smaller than those under isothermal conditions of 0.1×10−2 mg/mm2, 0.13×10−2 mg/mm2, 0.2×10−2 mg/mm2, and 0.35×10−2 mg/mm2. The corrosion rate under thermal cycling conditions was maintained at approximately 0.228×10−3 μm/h, while under isothermal conditions, the corrosion rate ranged from a minimum of 0.427×10−3 μm/h to a maximum of 0.1458×10−2 μm/h. Through observation, layers of Cr2O3, NiO, and Fe2O3 were identified. The intermediate layer of Fe2O3 plays a protective role against potential dissolution triggered by the molten salt in the inner Cr2O3 and NiO layers.

Subsurface A-site vacancy activates lattice oxygen in perovskite ferrites for methane anaerobic oxidation to syngas

Tuning the oxygen activity in perovskite oxides (ABO3) is promising to surmount the trade-off between activity and selectivity in redox reactions. However, this remains challenging due to the limited understanding in its activation mechanism. Herein, we propose the discovery that generating subsurface A-site cation (Lasub.) vacancy beneath surface Fe-O layer greatly improved the oxygen activity in LaFeO3, rendering enhanced methane conversion that is 2.9-fold higher than stoichiometric LaFeO3 while maintaining high syngas selectivity of 98% in anaerobic oxidation. Experimental and theoretical studies reveal that absence of Lasub.-O interaction lowered the electron density over oxygen and improved the oxygen mobility, which reduced the barrier for C-H bond cleavage and promoted the oxidation of C-atom, substantially boosting methane-to-syngas conversion. This discovery highlights the importance of A-site cations in modulating electronic state of oxygen, which is fundamentally different from the traditional scheme that mainly credits the redox activity to B-site cations and can pave a new avenue for designing prospective redox catalysts.

Corrosion protection characteristics of doped magnetite layers on carbon steel surfaces in aqueous CO2 environments

Magnetite (Fe3O4) corrosion product surface layers can limit uniform corrosion rates of carbon steel in aqueous carbon dioxide (CO2)-saturated environments. However, as Fe3O4 is a semiconductor, localised corrosion can proceed due to galvanic interaction between the Fe3O4 layers and bare steel. In this study, metal dopants were integrated into Fe3O4 layers to mitigate the effects of localised corrosion, whilst maintaining its protective barrier properties. Model Fe3O4 and metal-doped Fe3O4 layers were electrodeposited on carbon steel and immersed in a pH 5, 1 wt% sodium chloride (NaCl), CO2-saturated, 50 °C solution. Under the conditions studied, the incorporation of magnesium into the Fe3O4 layer resulted in reduced localised corrosion when the 3D surface profiles of the underlying carbon steel were measured using white light interferometry.

A multiphysics model for predicting spatiotemporal temperature profiles in microwave-heated carbon capture processes

Due to alarming rise in atmospheric CO2 ppm levels, the direct air capture process has been engineered to capture low concentrations of CO2 directly from the atmosphere using chemisorbents. However, the regeneration of chemisorbents can be energy-intensive and may not always be efficient. To potentially enhance this, microwave is employed for selective and targeted heating of the chemisorbent. Existing measurement techniques struggle to accurately capture the spatiotemporal temperature profile of solvent impregnated polymer (SIP) under microwave heating. Therefore, it becomes crucial to determine the spatiotemporal temperature distribution inside the polymer phase to expedite CO2 desorption, improve energy efficiency, and prevent material degradation. Motivated by these considerations, we propose a 3D-multiphysics model to study the spatiotemporal distribution of temperature inside a hybrid nanoscale multi-functional material. We focus on the microwave heating of a novel heterogeneous system comprising a SIP with a ferromagnetic additive (Fe3O4), further solving the heat diffusion and Maxwell’s electromagnetic equations to analyze the temperature variation inside the SIP system. By coupling the physics of electromagnetism and heat transfer, our model allows for a comprehensive analysis of the temperature distribution and heating effects inside the chemisorbent. Additionally, we conduct sensitivity analysis of spatiotemporal temperature profile on various thermal and dielectric parameters, as well as the size and location of the Fe3O4 layer. These results can help to optimize desorption rates and make the regeneration process more energy-efficient in future studies.

Double-Shelled Fe-Fe3C Nanoparticles Embedded on a Porous Carbon Framework for Superior Lithium-Ion Half/Full Batteries.

Cost-effective and environmentally friendly Fe-based active materials offer exceptionally high energy capacity in lithium-ion batteries (LIBs) due to their multiple electron redox reactions. However, challenges, such as morphology degradation during cycling, cell pulverization, and electrochemical stability, have hindered their widespread use. Herein, we demonstrated a simple salt-assisted freeze-drying method to design a double-shelled Fe/Fe3C core tightly anchored on a porous carbon framework (FEC). The shell consists of a thin Fe3O4 layer (≈2 nm) and a carbon layer (≈10 nm) on the outermost part. Benefiting from the complex nanostructuring (porous carbon support, core-shell nanoparticles, and Fe3C incorporation), the FEC anode delivered a high discharge capacity of 947 mAh g-1 at 50 mA g-1 and a fast-rate capability of 305 mAh g-1 at 10 A g-1. Notably, the FEC cell still showed 86% reversible capacity retention (794 mAh g-1 at 50 mA g-1) at a high cycling temperature of 80 °C, indicating superior structural integrity during cycling at extreme temperatures. Furthermore, we conducted a simple solid-state fluorination technique using the as-prepared FEC sample and excess NH4F to prepare iron fluoride-carbon composites (FeF2/C) as the positive electrode. The full cell configuration, consisting of the FEC anode and FeF2/C cathode, reached a remarkable capacity of 200 mAh g-1 at a 20 mA g-1 rate or an energy density of approximately 530 Wh kg-1. Thus, the straightforward and simple experimental design holds great potential as a revolutionary Fe-based cathodic-anodic pair candidate for high-energy LIBs.

Perpendicular magnetic anisotropy in the multilayer fabricated by alternate sputtering of Fe3O4/Cr and post-annealing

Magnetic properties of sputter-deposited Fe3O4/Cr multilayers followed by annealing in vacuum were investigated. The saturation magnetization and perpendicular magnetic anisotropy were enhanced by post-annealing and the maximum perpendicular anisotropy of 3.3 Merg/cm3 was obtained in this study. From the results of X-ray photoelectron spectroscopy and X-ray diffraction, it was found that metallic Fe layers were formed in Fe3O4 layers due to the migration of oxygen atoms from Fe3O4 to Cr layer proceeded by the post-annealing. The large perpendicular anisotropy was considered to arise from the interface between Fe and Fe-oxide layers.

Charge pattern detection through electrostatic array sensing

As reported in previous work, electrostatic charge induced by contact potential difference (CPD) arising from oxidational wear can be detected by electrostatic button sensors. However, to detect signs of localised wear and to investigate the mechanisms involved, the charge distribution on worn regions needs to be measured. Therefore, this paper investigates the evolution of surface charge during wear processes, its interplay with friction, and the correlation between charge distribution and surface chemistry. An electrostatic bar sensor and an array sensor were initially calibrated using CPD patterns generated by dissimilar metal inserts in steel plates. After appropriate signal processing, the sensor outputs exhibited excellent agreement with the electric field strength modelled using COMSOL Multiphysics. Subsequently, the bar sensor was integrated into a reciprocating tribometer for in-situ detection of oxidational wear of steel-on-steel rubbing contacts, followed by ex-situ array sensing of worn regions. Positive picocoulomb-level surface charge during the evolution of oxidational wear were successfully detected by the bar sensor and were found to correlate to changes in friction coefficient. The array sensor effectively mapped the distribution of surface charge. EDS mapping suggested patchy formation of Fe3O4 layers over the worn areas, and these patches correlated to the surface charge map. Increased electrostatic charge levels were associated with higher concentrations of oxidational wear. Therefore, this paper evaluates the potential of electrostatic array sensors to spatially resolve surface charge patterns induced by surface chemistry transformations, which enables the monitoring of localised and smaller-scaled machinery component deterioration and provides additional information for machinery diagnosis.

Effect of Tungsten Inert Gas Remelting on Microstructure and Corrosion Resistance of Q450NQR1 High-Strength Weathering Steel-Welded Joints.

In this paper, the corrosion environment of a railway coal truck was simulated with 1.0%H2SO4 + 3%NaCl solution. The effect of weld toe Tungsten Inert Gas (TIG) remelting on the microstructure and corrosion resistance of welded joints of Q450NQR1 high-strength weathering steel was studied. The results show that the weld toe melts to form a remelting area after TIG remelting. After TIG remelting, the weld geometry was improved, and the stress concentration factor decreased from 1.17 to 1.06 at the weld toe, a decrease of 9.4%. TIG remelting refines the microstructure of the weld toe and improves the corrosion resistance of the welded joint. The surface of the TIG-remelted sample is uniformly corroded with no "deep and narrow" pits after the removal of corrosion products. The weight loss rate and corrosion rate of remelted welds are lower than those of unremelted welds. The structure of corrosion products is loose at the initial stage of corrosion, and the corrosion products are transformed into Fe3O4 and Fe2O3 protective rust layers with a dense structure after 480 h of corrosion. With the extension of corrosion time, the tensile strength and percentage elongation of the specimen decreased linearly. The decreasing rates of tensile strength of remelted and unremelted specimens were 0.09 and 0.11, respectively, and the decreasing rates of elongation after fracture were 0.0061 and 0.0076, respectively.

Synergistic mechanism of the fretting wear resistance of Fe2O3/Ag nanostructured coatings prepared by sliding friction and magnetron sputtering

The synergistic effect of the hard/soft phases of a material is potentially valuable and significant for improving wear resistance. Given this, a method for preparing Fe2O3/Ag nanostructured coatings, in which reciprocating sliding friction is used to prepare nano-Fe2O3 coatings and magnetron sputtering is used to prepare nano-Ag coatings, is proposed. The fretting wear test using a SiC ball as the friction pair shows that a large amount of oxide accumulates on the friction pair surface of the substrate, while that of the coating is smooth, and the coating greatly improves the wear resistance of the sample. In particular, the Fe2O3/Ag coating has better fretting wear resistance, and the wear rate is as low as 7.03 × 10−6 μm3N−1μm−1. The excellent tribological properties of Fe2O3/Ag nanostructured coatings at room temperature are derived from the Ag–Fe2O3 nanocomposite layer with a Ag composition gradient, which is formed by Ag nanoparticles gradually penetrating into the Fe2O3 layer under the normal load produced during fretting wear. Furthermore, the Ag/Fe2O3 semi-coherent interface, which is induced between Ag and Fe2O3 nanoparticles under fretting wear, endows the composite layer with excellent thermal and mechanical stability. This design idea of using a fretting wear load to prepare composite coatings with the synergistic effect of hard and soft phases to strengthen the wear performance of a workpiece also provides a reference for the preparation of other hard/soft heterogeneous coatings.

Effect of formic acid (HCOOH) on the corrosion protectiveness of magnetite (Fe3O4) at elevated temperature

The corrosion behavior of carbon steel in an aqueous solution containing dissolved CO2, H2S, and HCOOH at high temperature was investigated by conducting a series of systematic experiments. The influence of each (possible) corrosive species (CO2, H2S, and HCOOH) on corrosion mechanisms were explored through detailed analysis of corrosion rates and corrosion product layers. The results showed that the formation and integrity of the Fe3O4 layer was compromised in the presence of HCOOH, probably due to the formation of Fe(COOH)+which impedes the formation of Fe3O4 at the initial stage of the corrosion process.

Multifunctional molecularly imprinted nanozymes with improved enrichment and specificity for organic and inorganic trace compounds.

Although nanozymes exhibit properties superior to those of natural enzymes and conventional engineered enzymes, the development of highly specific nanozymes remains a challenge. New yolk-shell Fe3O4 molecularly imprinted (MIP@void@Fe3O4) nanozymes with peroxidase-like activity were developed by modelling the substrate channels of natural enzymes through molecular imprinting techniques and interfacial affinity modifications in this study. To establish a platform technology for the adsorption and determination of inorganic and organic contaminants, lead ion (Pb2+) and diazinon (DIZ), respectively, were selected as imprinting templates, and a hollow mesoporous shell was synthesized. The as-prepared MIP@void@Fe3O4 nanozymes, characterized using TEM, HRTEM, SEM, FT-IR, TGA, VSM and XPS, not only affirmed the successful fabrication of a magnetic nanoparticle with a unique hollow core-shell structure but also facilitated an exploration of the interfacial bonding mechanisms between Fe3O4 and other shell layers. The enrichment of the MIP@void@Fe3O4 nanozymes due to imprinting was approximately 5 times higher than the local substrate concentration and contributed to the increased activity. Based on selective and competitive recognition experiments, the synthesized nanozymes could selectively recognize organic and inorganic targets with the lowest detection limits (LOD) of 6.6 × 10-9 ppm for Pb2+ and 5.13 × 10-11 M for DIZ. Therefore, the proposed biosensor is expected to be a potent tool for trace pollutant detection, which provides a rational design for more advanced and subtle methods to bridge the activity gap between natural enzymes and nanozymes.