Graphite Composites Research Articles

Development and Characterization of 3D-Printed PLA/Exfoliated Graphite Composites for Enhanced Electrochemical Performance in Energy Storage Applications

This research introduces a new way to create a composite material (PLA/EG) for 3D printing. It combines polylactic acid (PLA) with exfoliated graphite (EG) using a physical mixing method, followed by direct mixing in a single-screw extruder. Structural and vibrational analyses using X-ray diffraction and Fourier transform infrared spectroscopy confirmed the PLA/EG’s formation (composite). The analysis also suggests physical adsorption as the primary interaction between the two materials. The exfoliated graphite acts as a barrier (thermal behavior), reducing heat transfer via TG. Electrochemical measurements reveal redox activity (cyclic voltammetry) with a specific capacitance of ~ 6 F g−1, low solution resistance, and negligible charge transfer resistance, indicating ion movement through a Warburg diffusion process. Additionally, in terms of complex behavior (electrochemical impedance spectroscopy), the PLA/EG’s actual capacitance C’(ω) displayed a value greater than 1000 μF cm−2, highlighting the composite’s effectiveness in storing charge. These results demonstrate that PLA/EG composites hold significant promise as electrodes in electronic devices. The methodology used in this study not only provides a practical way to create functional composites but also opens doors for new applications in electronics and energy storage.

Modulating the energy harvesting with tunable hardness from mildly functionalized graphite nanoplatelets-based composites for wearable applications

It is challenging to obtain balanced properties with good stretchability, mechanical stability, small response time, high output voltage, and finally optimum mechanical hardness. Thus, the present work supports that balanced properties can be obtained with good interfacial interactions during composite fabrication. Here, the ingredients involve the addition of mild functionalized graphite nanoplatelets (mf-GNP), silicone oil, and vulcanizing agents into the silicone rubber (SR) as a rubber matrix. The justification for the “mild” functionalization of GNP was validated through spectroscopic studies in this work. Robust functional groups like carboxyl (O-H), carbonyl (C=O), epoxy, and alkoxy (C-O) on the surface of mf-GNP expect improved interactions with the SR matrix. Moreover, results show that adding 5 per hundred parts of rubber (phr) of mf-GNP in the SR matrix increases compressive modulus, hardness, and stretchability. However, the addition of a different content of thinner lowers the hardness making the composites mechanically soft and ultrasoft. For example, the hardness was 25 (control sample), 27 (5 phr of mf-GNP filled sample)., 24 with 10 phr thinner (T10 sample), and finally 16 with 30 phr of thinner (T30 sample). The results further insight the stretchability was increased with different contents of mf-GNP or thinner in the SR matrix. For example, stretchability was 111% (control sample), 144% (5 phr of mf-GNP filled sample), 156% (T10 sample), and finally 129% (T30 sample). Also, the energy harvested tests were performed to obtain output voltage and response time for industrial applications of this work. For example, the response time at 30% compressive strain was 154 milliseconds (ms) (5 phr of mf-GNP filled sample), 184 ms (T10 sample), and finally 225 ms (T30 sample). The power density was ~2.65 nanowatt per centimeter square (nW/cm2) (mf-GNP sample), ~8.34 nW/cm2 (T10 sample), and finally ~1.69 nW/cm2 (T30 sample). Moreover, the piezoelectric coefficient was 14.5 picocoulomb per Newton (pC/N) (mf-GNP sample), 66.2 pC/N (T10 sample), and finally 19.37 pC/N (T30 sample). Finally, the results support the T10 sample as best with the balance of good stretchability, relatively optimum response time, higher durability, and finally good output voltage.

Reduced lattice spacing of birnessite type manganese dioxide/ expanded graphite cathode for stable aqueous zinc-ion batteries

Manganese oxides (MnOx) have attracted much attention due to abundant resource, low cost and eco-friendliness. In this study, birnessite type manganese dioxide/expanded graphite composites (KMO/EG) with a reduced lattice spacing of nanoflower and nanowire heterostructure KMO have been synthesized by a one-step hydrothermal method. The morphology of KMO has transformed from nanoflower to nanowire with a reduced lattice spacing due to nucleation sites on the surface of EG. The KMO/EG achieves a specific capacity of 444.5mAh g−1 and remains at 387.9mAh g−1 after 100 cycles at 0.1 A g −1 for Zn-ion battery. The enhanced specific capacity of KMO/EG is mainly attributed to the capacity contribution of EG and the good stability is related to the more stable structure of KMO caused by reduced lattice spacing.

Advancing self‐lubricating technology: Selective laser sintering molding assisted development of copper‐based polytetrafluoroethylene /graphite composites

AbstractThis study introduces an innovative technique for the fabrication of copper‐based polytetrafluoroethylene (PTFE)/graphite self‐lubricating composites. By harnessing the exceptional capabilities of selective laser sintering (SLS), we efficiently create three‐dimensional, continuous, and porous graphite preforms. Following this, the composite is formed through a combination of electroplating and vacuum extrusion methods. Subsequently, PTFE was vacuum impregnated into the microporous structure of the graphite preforms, and the composites were obtained through freeze‐drying, plasticizing, and machining processes. The resulting copper‐based PTFE/graphite self‐lubricating composites exhibit an exceptional blend of properties. Notably, there is a significant reduction in the average coefficient of friction, dropping from 0.14 to 0.02, and a marked decrease in the wear rate, from 1.358 × 10−5 to 1.109 × 10−5 mm3/N·m, as compared to graphite as a standalone lubricant. This represents a substantial improvement in performance, underscoring the effectiveness of the proposed fabrication method.Highlights The porous graphite with controllable shape distribution was prepared. Surface copper plating improves surface bonding. Controllable copper matrix composites with double lubricant were prepared. The average friction coefficient is as low as 0.02.

A composite anode based on intercalation and conversion mechanism for high-rate lithium-ion batteries

To increase the specific capacity and cycle stability of lithium-ion batteries at high current density, we have investigated the anode materials. Among them, black phosphorus has attracted attention because of its large theoretical specific capacity (2596 mA h/g). However, the moderate conductivity of black phosphorus itself makes it less effective. The addition of graphite to form P-C and P-O-C bonds with black phosphorus enhances the performance of the battery cell. Lithium ions are primarily stored in black phosphorus-graphite layered structural materials via an intercalation mechanism, which improves electrochemical performance at tiny current density but is inadequate for charge/discharge cycling at high current density. In addition, lithium ions also can undergo conversion mechanism with metal oxide materials (e.g. Tungsten trioxide). While this conversion mechanism enables more stable battery cycling at high current density, the specific capacity remains insufficiently high. Higher charge/discharge specific capacity and long cycle stability of lithium-ion batteries at high current density can be realized by the joint action of the two mechanisms. In this work, black phosphorus, graphite, and tungsten trioxide (BP/G/WO3) composites are prepared by ball milling method. A comprehensive series of electrochemical analyses reveals that the BP/G/WO3-532 electrode (BP, graphite, and WO3 mass ratio of 5:3:2) exhibits the most substantial enhancement in the cycling stability of lithium-ion batteries. The anode exhibits a high specific capacity of 1463.1 mA h/g at 6 A/g and presents a retention capacity of 1159.8 mA h/g after 300 charge/discharge cycles, indicating a high cycle stability and fast reaction kinetics. This result is mainly attributed to the joint action of two mechanisms of composites.

Upcycling Spent Graphite from Li-ion Batteries into Cu/Expanded Graphite Composites as high-performance electromagnetic wave absorbers.

With the widespread adoption of lithium-ion batteries and modern electronic components in both daily life and industrial production, there is a growing focus on the high-value recycling of spent lithium-ion batteries and the development of absorbents with high electromagnetic wave absorption capabilities. Efficiently regenerating recycling graphite from spent batteries through low-cost methods and utilizing it to prepare high-performance electromagnetic wave absorbing materials holds significant importance in addressing both the utilization of waste graphite and electromagnetic pollution issues simultaneously. This work presents a method to transform spent graphite into expanded graphite with a three-dimensional conductive structure using an enhanced Hummer's treatment and thermal reduction process. Subsequently, Cu/EG composite materials were efficiently prepared through straightforward mechanical ball milling and calcination. The unique honeycomb-like porous structure of expanded graphite facilitates the reflection and scattering of electromagnetic waves, electron transfer, and defect polarization. Additionally, the incorporation of copper nanoparticles improves the conduction loss and enhances interface polarization, allowing for precise tuning of the composite material's absorption performance. The results demonstrate that Cu/EG composite materials exhibit excellent electromagnetic wave absorption performance. The Cu/EG(1:3) sample exhibits effective absorption in the C, X, and Ku bands, achieving a minimum reflection loss (RLmin) of -54 dB and a maximum effective absorption bandwidth (EABmax) of 5.28 GHz. This performance is attained with a thickness of just 2.2 mm and a filler content of only 15 wt.%.

Effect of graphite on microstructure and friction-wear properties of yttria-stabilized zirconia coatings

Yttria-stabilized zirconia and flake graphite composite (C/YSZ) coatings were successfully prepared on a TC4 substrate by electrophoretic co-deposition and sintering at 1,100°C using YSZ nanopowder and flake graphite. The effects of the graphite content on the microstructure and friction-wear properties were investigated. The results indicated that flake graphite agglomerated in the C/YSZ coating. The YSZ coating with 0.6w.% graphite exhibited the highest toughness with the plastic resistance index (H/E) of 0.0172, which was 6.8% higher than that of the YSZ coating, and effectively inhibited the formation of coating cracks. However, an increase or a decrease in the graphite content led to a decrease in the toughness of the C/YSZ composite coating. The agglomerated graphite in the C/YSZ composite coating acted as a solid lubricant and affected friction and wear properties. The coefficient of friction (COF) of the 0.6C/YSZ sample was 0.45, which was 40% lower than that of the YSZ sample. The reason for this was that graphite effectively inhibited the falling-off of debris from the coating surface and reduced abrasive wear. However, an excessive amount of graphite, i.e., in case of the 0.8C/YSZ coating, decreased the roughness of the wear surface, leading to a reduction in the H/E and COF by 24.4% and 29.7%, respectively.

Ionic Liquid-Modified Copper for the Enhanced Thermal Conductivity and Mechanical Properties of Epoxy Resin/Expanded Graphite Composites.

In this study, diglycidylether of bisphenol A (DGEBA)/expanded graphite (EG)/copper (Cu) powder composites with high thermal conductivity were prepared for use as thermal interface materials. To construct an excellent thermally conductive network, the Cu surface was modified using the ionic liquid 1-ethyl-3-methyl imidazolium dicyanamide. In addition, the effect of the Cu content on the thermal conductivity, thermal stability, flexural properties, impact strength, and morphologies of the DGEBA/EG/Cu composites was investigated. The results indicated that the addition of 10 wt % Cu increased the thermal conductivity of the composites from 7.35 to 9.86 W/(m·K). Conversely, the thermal stability of the composites decreased with the addition of Cu. The flexural strength and impact strength of the composites increased from 27.9 MPa and 0.81 kJ/m2 to 39.6 MPa and 0.96 kJ/m2, respectively, as the Cu content increased from 0 to 10 wt %. Moreover, the flexural modulus of the composites increased from 9632 to 11,309 MPa with the addition of 10 wt % Cu. Scanning electron microscopy analysis of the DGEBA/EG/Cu composites revealed sheet-shaped blocks with numerous microcracks on the fracture surfaces.

Ultrathin Porous Carbon Nitride Anchored with Pt Nanoclusters for Synergistic Enhancement of Hydrogen Production in Alkaline Photocatalytic Polyester Reforming.

Photocatalytic reforming (PR) of polyester waste, fueled by renewable sources like solar energy, offers a sustainable method for producing clean H2 and valuable by-products under mild conditions. The design of high-performance photocatalyst plays a pivotal role in determining the efficacy of an alkaline polyester PR system, influencing H2 generation activity and selectivity. Here, ultrathin porous carbon nitride nanosheets (UP-CN) loaded with Pt nanoclusters (Pt NCs, average diameter of 1.7nm) with uniform Pt NCs distribution are introduced. The resulting Pt NCs/UP-CN catalyst can accelerate charge and mass transfer while providing additional active sites, achieving superior H2 generation rates of 11.69mmol gcat -1 h-1 and 2923mmol gPt -1 h-1 under AM 1.5 light, which nine times higher than that of Pt nanoparticles-bulk graphitic carbon nitride composite (1.29mmol gcat -1 h-1 and 258mmol gPt -1 h-1) as counterpart. This performance also surpasses that of previously reported carbon nitride-based and TiO2-based photocatalysts. Moreover, the density functional theory calculations reveal a significant reduction in the energy barrier for the water dissociation step (H2O + * → *H + OH) at the interface between UP-CN and anchored Pt NCs, showcasing the synergistic effect between Pt NCs and UP-CN. This catalytic system also exhibits universality across various polyester plastics.

Microstructural, mechanical, and wear properties of Sn-based solder alloy modified with graphite nanoparticles

This study investigated the microstructural, mechanical, and wear properties of the Sn-2.5 wt%Ag-0.4 wt%Cu-1.0 wt%In (SAC-1.0In) solder alloy including nano-graphite (0.6–1.2 wt%). The microstructural characteristics of several samples were investigated using optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive x-ray spectrometry (EDS), electron probe microanalysis (EPMA), x-ray diffraction (XRD), and x-ray photoelectronic spectroscopy (XPS). The results of this study revealed that the presence of nano-graphite particles stimulated the production of distinct intermetallic compound phases (IMC) identified as Ag3Sn, Cu6Sn5, and γ-InSn4. These IMCs are uniformly dispersed throughout the matrix. The results showed that the addition of nano-graphite particles did not significantly alter the morphology of the microstructure but reduced the particle size of these IMCs. This refining of precipitated IMC particles resulted in considerable improvements in the material’s mechanical properties. The wear properties of both unreinforced matrix and graphite composites were investigated utilizing a pin-on-disc tribometer. The addition of 0.6, 0.9, and 1.2 wt% graphite nanoparticles decreased the sliding wear rate. It is worth noting that the current study is deemed unique and novel in terms of total strain percent behavior as graphite content increases.

Biomimetic structure-driven high strength and toughness in continuous SiC skeleton-reinforced graphite composites

Graphite-matrix structural composites with excellent mechanical properties and long-term reliability are ungently required in aerospace and nuclear industries. However, the enhancement of graphite-matrix composites by mainstream surface coating techniques or second-phase particle reinforcement is rather limited. Inspired by the structural-functional feature of plant cells, silicon carbide (SiC, cytoderm) coated mesocarbon microbeads (MCMB, cytoplasm) powders were prepared by combustion synthesis (CS), which were then densified via spark plasma sintering (SPS) to obtain the biomimetic cellular-structured SiC-reinforced MCMB (M@SiC) composites. The in-situ formed SiC ‘cytoderm’ ensures good interfacial bonding and contributed to the densification of the composites. Additionally, the continuous SiC skeleton and cellular-structured configuration improved the mechanical properties of M@SiC composites. Owing to the complex crack deflection, branching and bridging effects at the MCMB/SiC interfaces and graphite nanoflakes inside MCMB, the biomimetic M@SiC composite with SiC content of 47 vol% exhibited strengthening and toughening, with flexural strength and fracture toughness of 245 MPa and 3.82 MPa m1/2, respectively. The developed biomimetic graphite-matrix composites with excellent mechanical properties are expected to be applied in reusable spacecrafts and high-temperature gas-cooled reactors.

Enhanced mechanical, tribological and corrosion properties of graphite and carbon nanotube-reinforced copper-based hybrid composites

Copper (Cu)-based hybrid composites were fabricated by powder metallurgy, incorporating Graphite (Gr) and Carbon nanotube (CNT) reinforcements at various fractions. The composites were formed using a cold pressing technique and subsequently sintered at various temperatures. The structural properties of the hybrid composites were evaluated using Scanning Electron Microscopy (SEM), Energy Dispersion Spectrum (EDX) and X-ray diffraction (XRD). Hardness, compression, wear and corrosion tests were performed to show the effect of the reinforcements. It was shown that the hardness of Gr and CNT reinforcements have significantly improved the properties of pure Cu. The Cu-Gr-2CNT hybrid composite, which was subjected to sintering at a temperature of 850°C, exhibited the highest level of hardness, showing a significant increase of 51.4% in comparison to the pure Cu sample. While the compressive stresses increased in the Cu matrix with the addition of Cu-Gr, it increased to 350 MPa with the addition of 2 wt% CNT. The hardness value exhibited a similar increase and was measured to be 122 HV in Cu-Gr-2CNT. During the wear tests, the coefficient of friction values fell by 9.2% for Cu-2CNT, by 3.88% for Cu-CNT, by 3.92% for Cu-Gr-2CNT, and by 5.27% for Cu-Gr-CNT, as compared to pure Cu. The comprehensive findings demonstrated that the tests and analyses yielded consistent results, and the utilization of various combinations of Gr and CNT reinforcements enhanced the mechanical, tribological, and corrosion resistance properties of the fabricated hybrid composites. Nevertheless, the combination of Cu-Gr-2CNT yielded the most advantageous outcomes.

Multiscale study on the solid-liquid synergistic lubrication mechanism of graphite and liquid lubricant in polymer composites

Solid-liquid synergistic lubrication, in combination with the advantages of solid and liquid lubrication, has gained the great popularity in recent years. However, the mechanism of solid-liquid synergetic lubrication is still unclear. In this paper, graphite and poly α-olefin base oil (PAO) were used as self-lubricating additives to evaluate their synergistic effect. The results show that the composites possess good mechanical and excellent tribological properties with a nanoindentation modulus of 3.8 GPa, a coefficient of friction of 0.0998, as well as a wear rate of 1.3 × 10−14 m3/N·m. Both transfer film and lubricating oil film exist on the friction interface, and the lubricating oil film protects the counter ball from excessive oxidation. At the same time, with combination of molecular dynamics (MD) simulation and first-principles calculations, the synergistic lubrication mechanism of graphite and PAO was manifested. PAO destroyed the interlayer structure of graphite, making it easier to form a transfer film on the counter ball surface. The weak chemical bond between graphite and PAO facilitates more PAO molecules to gather at the interface while forming the transfer film, which benefits the formation of lubricating oil film. The synergistic effect of graphite and PAO molecules is critical in promoting the further reduction of COF.

Carbon Dioxide Capture on Oxygen- and Nitrogen-Containing Carbon Quantum Dots.

To address global climate change challenges, an effective strategy involves capturing CO2 directly at its source using a sustainable, low-cost adsorbent. Carbon quantum dots (CQDs), derived from lignin, are employed to modify the internal surface of an activated carbon adsorbent, enabling selective adsorption based on electrostatic interactions. By manipulating charge distribution on CQDs through either doping (nitrogen) or functionalization (amine, carboxyl, or hydroxyl groups), the study confirms, through classical molecular dynamics simulations, the potential to adjust binding strength, adsorption capacity, and selectivity for CO2 over N2 and O2. For simulations with a single component gas, maximum selectivities of 3.6 and 6.7 are shown for CO2/N2 and CO2/O2, respectively, at 300 K. Simulations containing a wet flue gas indicate that the presence of water increases the CO2/N2 and CO2/O2 selectivities. The highest CO2/H2O selectivity obtained from a CQD/graphite system is 4.3. A comparison of graphite and lignin-based carbon composite (LBCC) substrates demonstrated that LBCC has enhanced adsorptive capacity. The roughness of the LBCC substrate prevents the diffusion of the CQD on the surface. This computational study takes another step toward identifying optimal CQD atomic architecture, dimensions, doping, and functionalization for a large-scale CQD/AC adsorbent solution for CO2 capture.

Density-controlled thermal and mechanical properties of vertically aligned graphite foam-based polymer composites

The problem of thermal management of electronic devices leads to high demand of thermal interface materials (TIMs) with high thermal conductivity (TC) and softness. In this work, graphite foam (GFoam) was used to fabricate silicon rubber (SR) matrix-based TIMs by stacking and vertical cutting method. The obtained 75 vol% GFoam(100)/SR shows a high through-plane TC of 330.33 W m−1 K−1 due to the vertically aligned graphite layers. A strong correlation between the properties of the composites and the density of the fillers is found, providing a new perspective to adjust the properties of the composites. Composites with different proportions of GFoam and graphite film (GF) were prepared to further enhance the mechanical properties without obvious sacrifice of the thermal management performance. We believe that the design principles proposed in this work will be important for developing high-performance thermal management materials.

Ordered porous carbon nitride embedded with truncated carbon nanotubes for boosting photocatalytic degradation

Limited light absorption and low charge separation rates are the main obstacles for graphitic carbon nitride-based photocatalysts. In terms of these defects, an ordered-porous graphitic carbon nitride composites (PCN@CNT) modified with truncated carbon nanotubes (CNTs) were composited through hydrothermal-calcination method in this work. Due to their electron trapping ability, the CNTs can enhance visible light absorption, narrow the bandgap, and act as electron concentrators, achieving that spatial separation of photogenerated carriers can inhibit electron-hole pair recombination efficiently. In addition, a controllable ordered-porous structure was constructed to provide abundant active sites and mass transfer channels, shortening the carrier migration path. These two modifications acted synergistically to enhance the catalysts' performance. The top-performing sample in this work, PCN@CNT-1, showed significant improvement in photovoltaic performance and achieved a 97.7 % degradation of rhodamine B, with a photocatalytic degradation rate constant (k-value) more than three times that of PCN. This work demonstrates the potential for modification by coupling CNTs to design carbon-nitride-based photocatalysts with excellent catalytic performance, which can be used as catalysts for wastewater purification.

Balling behavior and diamond graphitization of metal-matrix diamond composites by selective laser melting: A quantitative investigation

Selective laser melting (SLM) is an effective and potential technology to prepare metal-matrix diamond composites (MDC). In this study, balling phenomenon and graphitization of diamond of CuSn10-diamond composites by SLM were investigated. By univariate analysis of laser power and scanning speed on the morphology of single track, the balling phenomenon is directly affected by the flowability and wettability of the molten pool. By introducing the concept of laser energy density, balling and diamond graphitization are quantitatively evaluated by the standard deviation σ of surface balling height and IG: ID value, respectively. Balling degree increases with laser energy density, but diamond-graphitization turns out to be the opposite. The CuSn10-diamond composites with low balling and no diamond-graphitization can be obtained at moderate laser energy density of 0.17 J/mm. In terms of performances, bending strength is mainly affected the defects caused by balling, and wear properties is determined by the graphitization of diamond abrasives. Graphitization of diamond results in the transformation of wear mechanism from abrasive to adhesive wear. The optimal properties of 185.36 MPa in bending strength, 0.41 in coefficient of friction and minimum wear loss is obtained in the composite sample prepared at 0.17 J/mm.

Hybrid effect of graphite and carbon fibers on thermal properties of copper/graphite/carbon fibers composites

To maintain the high thermal conductivity (TC) and reduce the coefficient of thermal expansion (CTE) of conventional copper (Cu)/graphite composites, novel Cu/graphite/carbon fibers (CFs) hybrid composites were designed by replacing part of graphite with Cu-coated CFs and prepared by spark plasma sintering (SPS) process. The incorporation of CFs resulted in increased interface density, reduced twin boundaries, and significant grain refinement of the Cu matrix. TEM observations revealed that the Cu-coating on surfaces of CFs enhanced the interfacial bonding between CFs and Cu matrix. The Cu-coated CFs can act as connecting channels between graphite particles, which partially compensate the negative effect on TC. Furthermore, strong interfacial bonding and large Cu/CFs contact areas contribute to the reduction in CTE. As a result, the Cu/30%graphite/10%CFs composite showed TC and CTE of 453.5 Wm−1 K−1 and 10.9 × 10−6 K−1, respectively. Compared to the Cu/40%graphite composite, the CTE of Cu/30%graphite/10%CFs composite was reduced by ∼20 % with only 4.4 % sacrifice in TC. Consequently, the Cu/graphite/CFs hybrid composites showed an excellent balance between TC and CTE, which are superior to the conventional Cu/graphite and Cu/CFs composites. The findings of this work provide new insights for designing and preparing new thermal management materials.

Enhancing mechanical properties and tribological performance through boron carbide hybridization in Novolac matrix graphite composites under dry sliding condition

This study extensively investigates the effects of 10 wt% graphite reinforcement and varying B4C content (1 wt%, 2 wt%, 4 wt%) on the properties of Novolac matrix polymer composites prepared by mechanical milling-assisted hot pressing. The microstructures, wear surfaces, wear debris, and fracture surfaces of the produced polymer composites were examined using SEM and EDS. The density measurements were conducted according to the Archimed’s principle. Their tribological behavior was evaluated with a reciprocating ball-on-flat sliding wear test at 50 N, 75 N, and 100 N loads. After the wear tests, surface topography was analyzed in 3D with an optical profilometer. The results indicated that composites with 2 wt% B4C had the lowest specific wear rate and the highest wear resistance.

Honeycomb polypore biomass-derived activated porous carbon nanosheets/graphite/nafion composite: Green and sensitive electrocatalyst for nanomolar detection of Hg2+ ions and water-splitting reactions

The electrochemical strategies with green electrocatalysts propose a selective, steady, and sensitive direction for the trace analytes sensing, hydrogen evolution reaction (HER), and oxygen evolution reaction (OER) applications. Herein, Honeycomb Polypore biomass waste-derived NaOH-activated porous nanocarbon material was synthesized, which performs as a multifunctional electrocatalyst for Hg2+ sensing and water-splitting reactions with the support of graphite and Nafion composite. The optimized nanocomposite shows high electrochemical activity for the redox reaction of Hg2+ in 0.1 M phosphate-buffered saline of 5.0 pH with a lower limit of detection value of 2.309 nM, good stability, reproducibility, and anti-interference activity. For water-splitting reactions, the optimized nanocomposite shows better overpotential values of 0.447 V (HER in 0.5 M H2SO4) and 0.305 V (OER in 0.5 M KOH) at 10.0 mA/cm2 of current density. Also, the lower Tafel slope values of 0.089 V/decade and 0.075 V/decade of the optimum electrocatalyst signify superior proficiency towards the HER and OER activities, respectively. These outcomes validate the materials’ excellent multifunctional activity for Hg2+ detection in different water samples and water-splitting reactions, boosting their potential for environmental safety and energy production.