Graphene Research Articles

Fe3O4/carbon-decorated graphene boosts photothermal conversion and storage of phase change materials

Pristine organic phase change materials (PCMs) are difficult to complete photothermal conversion and storage. To upgrade their photothermal conversion and storage capacity, we developed Fe-MOF (metal-organic framework) derived Fe3O4/C-decorated graphene (GP) based composite PCMs toward solar energy harvesting. Graphene is an excellent phonon conductor, and Fe3O4/C-GP as a photon capturer exhibits strong full-spectrum absorption. Additionally, Fe-MOF derived Fe3O4 nanoparticles are anchored on graphene nanosheets to reduce interfacial thermal resistance, shorten thermal diffusion path, and accelerate phonon transport. After the encapsulation of octadecanol (ODA) in Fe3O4/C-GP, ODA@Fe3O4/C-GP composite PCMs yield a high photothermal conversion efficiency of 88.18 % under 0.12 W/cm2 benefiting from the synergistic effect of 3D interconnected graphene framework and Fe3O4 nanoparticles with localized surface plasmon resonance effect. Moreover, ODA@Fe3O4/C-GP composite PCMs exhibit excellent latent heat storage stability, photothermal conversion stability and durable reliability after undergoing multiple cycle evaluation, boosting high-efficiency utilization of solar energy.

Investigation of the piezoelectric performance of P(VDF-TrFE)/SnO2NPs/GR composite film fabricated via electrospinning

ABSTRACT This paper introduces an innovative sandwich-structured piezoelectric nanogenerator film. In contrast to conventional piezoelectric generators, it exhibits enhanced flexibility and generates higher voltage. It can function as a self-sustaining power source for wearable sensors. To augment the film’s β-phase content, consequently boosting the nanogenerator’s voltage output, the nanofilm was manufactured through high-voltage electrospinning in poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)), incorporating stannic oxide nanoparticles (SnO2NPS) and graphene (GR).The relationship between the surface morphology, β-phase content, and voltage output performance of composite piezoelectric films with distinct compositions was comprehensively assessed and scrutinized utilizing scanning electron microscopy (SEM), X-ray diffraction (XRD) patterns, and vibration platforms. The findings reveal that the composition of 12% P(VDF-TrFE) + 5% SnO2NPS + 0.1% GR yields the finest fiber alignment, the highest β-phase content, as well as peak open-circuit voltage and short-circuit peak current values of 22.43 V and 12.95 μA, respectively. This signifies a 1.5-fold and 1.3-fold improvement compared to the film containing only SnO2NPS, and a 2.43-fold and 1.92-fold enhancement relative to the pure P(VDF-TrFE) film. Consequently, it achieves a maximum instantaneous output power of 64.578 μW. Securing the nanogenerator with the aforementioned composition to the sole of a shoe and running for 21 minutes can charge the capacitor to 4 V, thereby empowering it to operate commercial liquid crystal thermometers or approximately 80 LED lights for approximately 1.6 seconds. This technology possesses substantial significance within the realm of self-sustaining low-power electronic devices.

Investigating the optical absorption and thermal conductivity of nano-enhanced lauric acid phase change material for energy storage application

The issue of energy storage can be significantly reduced owing to phase change materials’ (PCMs) tremendous capacity for storing latent heat in a reliable and sustainable method. The limited thermal conductivity, however, prevents PCM from being widely used in a variety of uses. Highly conductive nanoparticles (NPs) are frequently integrated into PCMs to address this shortcoming. Due to their high thermal conductivity, such as Graphene (GR), carbon-based NPs are considered potential NPs to be implemented in PCMs. Herein, we report the Lauric acid (LA) PCM, and nano-enhanced LA with 0.3% and 0.7% additions of GR NPs. The composites were prepared by using two-step method. The samples were examined thermo-physically; thermal conductivity was obtained using a thermal property analyzer (TEMPOs), chemical composition was identified using Fourier transform infrared spectroscopy (FTIR), photo-transmittance by Ultra-Violet Visible spectra (UV-Vis) and thermal stability was assessed by employing thermal gravimetric analyzer (TGA). As per results, thermal conductivity of LA was enhanced by 13.5% and 18.4% by inclusion of 0.3 and 0.7 weight percentages of GR NPs. The 0.7 weight percentage addition of GR NPs to base PCM exhibited 60% transmittance reduction in comparison to base LA. Further all prepared samples were thermally stable with no weight degradation until 140°C. The FTIR confirmed the samples were chemically stable as no any new peak observed in composites. Therefore, based on results, GR enhanced LA PCM can be considered as future potential composite to be implemented in energy storage applications.

Design and application of a flexible nano cardiac sound sensor based on P(VDF-TrFE)/KNN/GR composite piezoelectric film for heart disease diagnosis

The paper proposes a flexible micro-nano composite piezoelectric thin film. This flexible piezoelectric film is fabricated through electrospinning process, utilizing a combination of 12 wt% poly(vinylidene fluoride-co-trifluoroethylene)(P(VDF-TrFE)), 8 wt% potassium sodium niobate (KNN) nanoparticles, and 0.5 wt% graphene (GR). Under cyclic loading, the composite film demonstrates a remarkable increase in open-circuit voltage and short-circuit current, achieving values of 36.1 V and 163.7 uA, respectively. These values are 5.8 times and 3.6 times higher than those observed in the pure P(VDF-TrFE) film. The integration of this piezoelectric film into a wearable flexible heartbeat sensor, coupled with the RepMLP classification model, facilitates heartbeat acquisition and real-time automated diagnosis. After training and validation on a dataset containing 2000 heartbeat samples, the system achieved an accuracy of approximately 99% in two classification of heart sound signals (normal and abnormal). This research substantially enhances the output performance of the piezoelectric film, offering a novel and valuable solution for the application of flexible piezoelectric films in physiological signal detection

Ternary system based on polyaniline, graphene, and acrylic matrix applied to thermoelectric systems

AbstractThermoelectric (TE) materials have attracted attention for offering a green option for power generation, due to their ability to convert thermal energy into electricity. In recent years, a promising way to achieve efficiency in TE properties has been proposed based on composites of conjugated polymers, such as polyaniline (PANI), and carbon nanomaterials such as graphene (GR). Since polyaniline and GR composites are promising fillers for organic thermoelectric materials (OTE), we expanded their investigations for a ternary system (TS), providing materials with multiple functionalities, and high performance. In this research work, a TS based on an acrylic matrix (ACR), GR, and PANI was successfully prepared through the combination of in situ polymerization of aniline in contact with GR and mechanical mixture of the resulting hybrid with an ACR. Structural and morphological characterization confirmed that GR affected PANI morphology and crystallinity. The band gap determination by Tauc's relation indicated the occurrence of π‐π interaction between the chains and an increase of the electrical conductivity of the composites allowed to infer a synergistic effect. The measured Seebeck coefficient reached a maximum value of −17.02 μVK−1 and the highest power factor obtained was 4.94 μWm−1 K−2 for the ACR/PANI sample, indicating a material with promising thermoelectric properties.

Mechanical and conductivity properties of 6061Al matrix composites reinforced with different pH Cu-coated graphene

ABSTRACT The lightweight designs of automobiles and space shuttles have raised the bar for aluminum (Al) and its alloys. Graphene (GP) has found widespread application in aluminum matrix composites due to its exceptional mechanical, electrical, and thermal properties. In this study, a successful preparation of 6061Al reinforced with GP was achieved through a powder metallurgy method. This involved mixing GP with 6061Al alloy powders via ball milling, followed by hot-pressing sintering to produce the final GP-reinforced Al alloy nanocomposite. The effect of the pH value of the plating solution on the electroless plating of GP has been studied for the first time. The results show that the strength of the aluminum-matrix composites with copper plating has been significantly improved compared with that of the composites without copper plating. When the pH value of the plating solution is 12, the tensile strength of the composites obtained has been increased by 60.41%. Compared with the matrix material, the conductivity of the composite material has also increased. This work shows that the mechanical behavior of graphene-reinforced metal matrix composites (MMCs) can be improved by adjusting the distribution of graphene coatings, which is of great benefit for the preparation of high strength and lightweight composites with good electrical conductivity.

Lowering polycyclic aromatic hydrocarbon concentrations in vegetable oil deodorizer distillates and enhancing its utilization by graphene composites

Vegetable oil deodorizer distillates (VODDs), which are the main source of natural tocopherol, are easily contaminated by polycyclic aromatic hydrocarbons (PAHs), and pose health threats to human beings. To remove 16 priority-control PAHs in VODD, three graphene (GR) composites, including TiO2-GR, sepiolite-GR and Fe3O4-GR, were prepared. PAH concentrations and removal rates were determined using gas chromatography-mass spectrum (GC-MS). Additionally, density functional theory (DFT) calculation was conducted to simulate and illustrate PAH adsorption on GR composites. The results indicated that the highest BaP removal rate was given to TiO2-GR with 90.37 ± 3.23 % after 2 h in standard solution. The adsorption followed the pseudo-first order kinetic, with the constant of −0.0141. In contrast, 61.62 ± 7.88 % total PAHs were removed in VODD using TiO2-GR. Moreover, DFT calculation verified that the strongest adsorption effect occurred between TiO2-GR and PAHs, with the adsorption energy of −2.69 eV. Additionally, GR composite morphology would be changed when LPAH concentrations are higher than 30 μg kg-1. The results also indicated the retention rates tocopherol ranged from 91.91 ± 1.92 % to 99.22 ± 0.88 %. This study firstly provides a useful tool for PAH removal in VODDs while retaining tocopherol. Moreover, it will increase the understanding of adsorption process between PAHs and GR composites.

A comparative study of graphite and graphene sheets employed in polymer‐based electromagnetic shielding materials

AbstractIn this work, the comparative properties of graphite (GT) and graphene (GE) sheets for use in polymer‐based electromagnetic (EM) shielding materials were explored. To accomplish this, GT and GE were individually combined with polyvinylidene fluoride (PVDF) as composite films and each was later attached to a nonwoven fabric to produce nonwoven‐reinforced (NR) films. The microtopography showed that GT was easily wrapped by the PVDF matrix in the composite film, whereas GE was partially exposed on the film surface because of its complete contact with PVDF. Addition of the carbon materials appeared to increase the EM shielding effectiveness (SE) of the films in the X‐band. The SE of the PVDF/GE films was significantly higher than the PVDF/GT films, up to 50.4 dB, which was mainly affected by electronic conductivity. The internal loss of the EM wave in PVDF/GE films was dominated by internal reflection because of the more regular arrangement of GE, whereas the loss in the PVDF/GT films contained greater EM absorption. Although the SE at 1–18 GHz of NR PVDF/GT film was significantly lower than the NR PVDF/GE film, the internal loss at high frequency was higher due to the better absorption loss in its surface layer.Highlights GT and GE sheets were compared as functional materials. GT and GE sheets showed different distribution states in the films. The EM SE of the PVDF/GE films was up to 50.4 dB. The EM shielding mechanism was analyzed and compared.

Designing Multielement nanointerfaces in supported catalysts by ultra small lattice mismatch

Catalysts supported by multiple functional constituents show exceptional catalytic performance, attributed to electron and energy exchanges occurring at the nanointerfaces between different subunits. Herein, the lattice-mismatch mechanism was used to guide the creation of a functional interface between cobalt oxide (CoO) and zinc oxide (ZnO) on a graphene (GN) support. By computing the lattice-mismatch between hexagonal wurtzite CoO (h-CoO) and ZnO, we achieve an exceptionally low value of 0.18 %. This ultra small lattice-mismatch facilitates the formation of interfaces when employing a seed-mediated growth approach, using a colloidal method for catalyst design. In this approach, CoO is expected to grow directly on ZnO particles, rather than on GN, when utilizing the ZnO/GN catalyst as heteroseed. The growth pattern of CoO follows the Frank − van der Merwe (FM) model, leading to the successful preparation of ZnO@CoO/GN. Similarly, ZnO readily interfaces with the CoO surface to form a nanointerface when the ZnO@CoO/GN catalyst is used as the seed. Interestingly, this epitaxial growth process can be repeated multiple times, resulting in increasingly diverse nano-heterostructures. The resulting catalyst exhibits outstanding performance in CO2 hydrogenation reaction due to the presence of dense CoO-ZnO nanointerfaces. The methodology presents a novel concept for the advancement of efficient supported catalysts.

Optimization of Piezoresistive Response of Elastomeric Porous Structures Based on Carbon-Based Hybrid Fillers Created by Selective Laser Sintering.

Recently, piezoresistive sensors made by 3D printing have gained considerable interest in the field of wearable electronics due to their ultralight nature, high compressibility, robustness, and excellent electromechanical properties. In this work, building on previous results on the Selective Laser Sintering (SLS) of porous systems based on thermoplastic polyurethane (TPU) and graphene (GE)/carbon nanotubes (MWCNT) as carbon conductive fillers, the effect of variables such as thickness, diameter, and porosity of 3D printed disks is thoroughly studied with the aim of optimizing their piezoresistive performance. The resulting system is a disk with a diameter of 13 mm and a thickness of 0.3 mm endowed with optimal reproducibility, sensitivity, and linearity of the electrical signal. Dynamic compressive strength tests conducted on the proposed 3D printed sensors reveal a linear piezoresistive response in the range of 0.1-2 N compressive load. In addition, the optimized system is characterized at a high load frequency (2 Hz), and the stability and sensitivity of the electrical signal are evaluated. Finally, an application test demonstrates the ability of this system to be used as a real-time wearable pressure sensor for applications in prosthetics, consumer products, and personalized health-monitoring systems.

GR-Fe3O4/PLA 3D printing composite materials with excellent microwave absorption properties

In this work, composite microspheres were formed by integrating graphene (GR) and Fe3O4 into an ethylcellulose matrix via an emulsion emulsification reaction. Composite wires were fabricated using a melt extrusion process and composite samples were subsequently prepared via a melt molding method. A systematic study was conducted to investigate the absorption performance of GR-Fe3O4/PLA (Polylactic acid) composite materials. The findings revealed that the optimal microwave absorption performance was achieved when the graphene content was 5.6 wt% and the Fe3O4 content was 11.1 wt%. The maximum reflection loss was − 51.13 dB at a thickness of 2.65 mm. The maximum absorption bandwidth was 4.16 GHz, and the effective radar interception cross-section was reduced to − 42.7 dBm2. The excellent performance of GR-Fe3O4/PLA composite material can be attributed to good impedance matching and the synergistic effect of conductive loss, dipole polarization, interface polarization, and eddy current loss. Then the contribution of conductive loss and polarization loss to the absorption performance was explored. This work provides a novel approach to advance the design and development of functional materials for efficient electromagnetic absorption, providing valuable insights into the development of efficient, lightweight microwave absorbing material.

Screening for the adsorption-activated H2O2 and peroxymonosulfate for high-performance heteroatom-doped graphene: Molecular dynamics simulation and DFT

As an green and efficient metal-free catalyst, heteroatom-doped graphene has gradually become a research topic in the catalytic field, but the active sites and mechanisms of the catalytic reactions are still not thorough enough. In this paper, the adsorption-activation properties of two activated molecules, H2O2 and peroxymonosulfate (PMS), on graphene (GR) and heteroatom (N, P, B, Si, F) doped graphene were investigated by means of computational methods. Molecular dynamics (MD) simulation results showed that the adsorption activation process of activated molecules on the surface of the six catalysts occurs in their first adsorption layer, in which B-doped graphene (BGR) has better catalytic activation performance for H2O2, while N-doped graphene (NGR) has better catalytic activation performance for PMS. Density function theory (DFT) revealed that the lowest molecular orbital gap of H2O2 at -BCO2 (0.691 eV), PMS at -NC2 has the lowest gap (0.432 eV). It is inferred that -BCO2 and -NC2 functional groups are the main functional regions of H2O2 activation by BGR and PMS activation by NGR, respectively. This work provides useful guidance for the design and optimization of high-performance metal-free catalysts, and the realization of green remediation for wastewater in the electrocatalytic oxidation process.

The novel design of an intelligent anti-depression transdermal drug delivery system

Depression is a type of mental disorder with a significant and persistent low mood as the main clinical feature. It is often accompanied by symptoms such as slow thinking, decreased will, loss of appetite, and weight loss. The current treatment methods for depression are mainly medical treatment, psychotherapy, and physical therapy. These treatments are dependent on the patient's autonomy and the patients may suspend treatment due to forgetting or refusing. Therefore, an anti-depressant intelligent drug release system was designed, which can achieve autonomously controlled doses for the treatment of depression by transdermal drug delivery system. The work of this study is as follows:(1) The first module: the electrothermal material heating layer. Several preparation methods were screened, and multiple sets of graphene (GE) electric thermogenic layers were successfully prepared. After increasing the actual energization area to 1 cm × 1 cm, the GE electric thermogenic layer is used as the heating layer of the electrothermal material of the system, and can reach a uniform surface temperature of (45 ± 0.5) °C within 15 s at a voltage of 6 V keeping the temperature fluctuation range not exceeding ±0.03 °C, and the resistance fluctuation range not exceeding ±20 Ω, which plays a role in controlling the temperature and heat treatment of the drug loaded gel layer.(2) The second module: the drug-loaded gel layer. Based on the L16 (45) orthogonal test, the best formulation and process of N-Isopropyl acrylamide-Acrylamide copolymer (P(NIPAAm-co-AAm)) hydrogel was determined. Then, the percutaneous permeability of Selegiline liposome was studied in vitro.(3) A rat model of depression was established using chronic unpredictable mild stress (CUMS) combined with separation. From the aspects of behavior (body weight, sucrose preference test, forced swimming test, open field test) and biochemical indexes (serum proinflammatory cytokines (IL-1β, TNF-α), hippocampus HE staining observation), the therapeutic effect of hyperthermia, Selegiline oral administration and transdermal administration was discussed.

A disposable immunosensor for the detection of salivary MMP-8 as biomarker of periodontitis

This work describes the development of a novel voltammetric immunosensor for the detection of salivary MMP-8 at the point-of-care. The electrochemical platform was based on a graphene (GPH) screen-printed electrode (SPE) functionalized by gold-nanospheres (AuNSs) and antibodies against MMP-8 protein (anti-MMP-8). The functionalization with anti-MMP-8 was realized by using 11-mercaptoundecanoic acid (11-MUA), thanks to its ability to give strong sulfur bonds with its –SH end, and to cross-link the –NH2 groups of the antibody molecule with the other –COOH end, using the traditional EDC-NHS method. The voltammetric sensor showed good performances with a linear range of 2.5–300 ng mL−1, a LOD value of 1.0 ± 0.1 ng mL−1 and a sensitivity of 0.05 µA mL cm−2 ng−1. Moreover, the proposed immunosensor was tested in real saliva samples, showing comparable results to those obtained with the conventional ELISA method. The biosensor was single-use and cost-effective and required a small quantity of test medium and a short preparation time, representing a very attractive biosensor for MMP-8 detection in human saliva.

Experimental study on preparation and properties of carbon nanotubes-, graphene –natural rubber composites

Carbon nanotubes (CNTs-), graphene (GNs)-natural rubber (NR) composites were prepared by wet mixing process and dry mixing process, respectively. Thermal conductivity, 300% tensile stress, tear strength and elongation at break of the samples were measured experimentally. The effects of mixing process, carbon materials content and type on thermal properties and mechanical properties of composites were studied. The experimental results show that, the thermal conductivity of the mixed rubber, the 300% tensile stress and the tear strength of the vulcanizate all increase first and then decrease slightly with the increase of the carbon material content, regardless of the mixing process. However, the elongation at break of vulcanizate showed an opposite trend. When the carbon material content is 2.0% (w.t.%), thermal conductivity, 300% tensile stress and tear strength all reach their maximum, while elongation at break obtains minimum. Under the same amount of addition, GNs is more conducive to improving the thermal conductivity and elongation at break of composites, while CNTs are more conducive to improving the tensile strength and tear strength of composites. For CNTs-, GNs-NR composites, the wet mixing process can greatly improve the thermal conductivity, tensile strength and tear strength of composites, while the dry mixing process can greatly improve the elongation at break of composites. Therefore, when preparing CNTs-, GNs-NR composites, it is necessary to select a suitable mixing process according to the performance requirements of the final product.

Effect of carbon nanomaterials on functional diversity and structure of soil microbial community under single and repeated exposures.

The extensive application of carbon nanomaterials (CNMs) has attracted increasing studies concerned about its environmental impact. These studies focus on single exposure to CNMs, but repeated exposures with relatively low concentration are more likely to occur under actual exposure scenario. In this study, we studied the metabolic functional and structure of soil microorganism community under single and repeated exposures to multiwalled carbon nanotubes (MW), graphene (GR), and fullerene (C60) by Biolog EcoPlates and high-throughput sequencing. Our findings revealed that repeated exposures to CNMs significantly increase the metabolic activity and diversity of the soil microbial community as compared with single exposure. Principal component and similarity analysis not only indicated that GR exerted a stronger effect on soil microbial diversity among three exposures compared to C60 and MW, but also revealed that the metabolic activity of the soil microbial community was more affected by the exposure scenarios of CNMs than the type of CNMs. These findings elucidated the effect of CNMs under different exposure scenarios on soil microorganism community, providing a new perspective on the risk assessment of nanomaterials.

Graphene-Based Composites for Biomedical Applications: Surface Modification for Enhanced Antimicrobial Activity and Biocompatibility.

The application of graphene-based materials in medicine has led to significant technological breakthroughs. The remarkable properties of these carbon materials and their potential for functionalization with various molecules and compounds make them highly attractive for numerous medical applications. To enhance their functionality and applicability, extensive research has been conducted on surface modification of graphene (GN) and its derivatives, including modifications with antimicrobials, metals, polymers, and natural compounds. This review aims to discuss recent and relevant studies related to advancements in the formulation of graphene composites, addressing their antimicrobial and/or antibiofilm properties and evaluating their biocompatibility, with a primary focus on their biomedical applications. It was concluded that GN surface modification, particularly with compounds intrinsically active against bacteria (e.g., antimicrobial peptides, silver and copper nanomaterials, and chitosan), has resulted in biomaterials with improved antimicrobial performance. Furthermore, the association of GN materials with non-natural polymers provides composites with increased biocompatibility when interfaced with human tissues, although with slightly lower antimicrobial efficacy. However, it is crucial to highlight that while modified GN materials hold huge potential, their widespread use in the medical field is still undergoing research and development. Comprehensive studies on safety, long-term effects, and stability are essential before their adoption in real-world medical scenarios.

A unique graphene composite coating suitable for ultra-low temperature and thermal shock environments

Traditional epoxy resin is prone to cracking and losing its protective properties under ultra-low temperature and thermal shock environments. The reason for coating failure is thermal stress damage caused by the mismatch of the thermal expansion coefficient (CTE) between the coating and substrate. Moreover, the brittleness of epoxy resin (EP) increases in ultra-low temperature environments. In order to reduce the CTE of the composite and improve the toughness of the coating, negative expansion graphene (GP) modified by a silane coupling agent (MP) is used as the filler of EP. The thermal stress of the coating under ultra-low temperature of −196 °C was analyzed by finite element simulation and the stress damage mechanism was explained. The simulation results show that the thermal stress of the coating decreases by 10–15 MPa after adding MP@GP. Simultaneously, MP@GP can act as a lamellar physical barrier, extend the penetration path of corrosive media, and inhibit the electrochemical corrosion of the metal surface. After 20 thermal shock tests, the MP@GP/EP coating remains intact without cracks and the |Z|0.01 Hz value of the 1 % MP@GP/EP coating reaches the highest at 3.99 × 1010 Ω·cm2. Therefore, the coating has unique thermal shock and corrosion resistance under multiple synergistic effects.

Versatile biomimetic catalyst functionalized nanozymes for electrochemical sensing

Electrochemical sensors face challenges in the readily accessible versatile sensing materials, robust signal transmission and selective detection of analytes in complex systems. Herein, we report a simple one-pot approach using commercially available materials to synthesize versatile biomimetic catalyst functionalized nanozymes for multifunctional electrochemical sensors. Nanoenzymes were synthesized by in situ polymerization of 3,4-ethylenedioxythiophene (EDOT) on graphene (GR) while integrating biomimetic catalysts into nanosheets. The resulting nanozymes exhibited stable and efficient catalysis activity and interfacial signal transmission through electrostatic and π-π interactions, as well as charge transfer at the active centers. By virtue of excellent electron transfer and favorable cascade catalysis effect, the biosensor based on sulfonated cobalt phthalocyanine functionalized nanozymes (CoPcNS) and acetylcholinesterase (AChE) exhibited superior catalytic activity and robust stability. This one-pot method was also used to prepare nanozymes with diverse biomimetic catalysts (metallophthalocyanine and metalloporphyrin), achieving specific detection of various biomolecules (H2O2, NO, etc.). A portable biosensing device based on a screen-printed electrode was developed, featuring a low limit of detection, ultralow working potential, high anti-interference capability, and good applicability for the rapid detection of organophosphorus pesticides (OPs) in real samples. Our research presents a promising guide for the rational fabrication of versatile biomimetic catalyst-functionalized nanozymes, advancing the development of electrochemical sensors in environmental and biological fields.

Synthesis of bio-based toughening phosphorus-nitrogen flame retardant and study on high toughness EPS flame retardant insulation sheet

In this paper, a variety of biological phosphorus-nitrogen synergistic flame retardants were synthesized from the perspective of molecular design. At the same time, tannic acid (TA) modified graphene (GE) and multiwalled carbon nanotubes (MWCNTs) nanomaterials were prepared by combining nanocomposite technology. Then, the flame retardant was applied to expandable polystyrene (EPS) through a coating process to prepare toughened composites. And the effect of the synthesized high-efficiency phosphorus-nitrogen flame retardant on the flame retardancy efficiency and brittleness of EPS was studied. The flame retardant (PAU) was synthesized by complexing phytic acid (PA) and urea (U) in an aqueous medium, and then using polydopamine (PDA) as an adhesive. Next, on the basis of PAU, using GE and MWCNTs as tougheners, EPS-PAUCG composites were prepared by coating method. Research has found that in the UL-94 test, the flame-retardant EPS-PAUCG composites could reach V-0 level. In the CCT experiment, compared to pure EPS, the PHRR, THR, PSPR, and TSP of EPS-PAUCG2 decreased by 88.4 %, 72.3%, 74.9 %, and 80.9 %, respectively. Through mechanism analysis, it has been proven that PAUCG undergoes thermal decomposition to form a dense expandable protective carbon layer, preventing further degradation of the matrix. In addition, compared to EPS, the compressive strength of the EPS-PAUCG2 composites have increased by 22.5%. This was because the composites contained GE and MWCNTs with high molecular chain structure rigidity and specific surface area, which had a toughening effect of ductile particles.