Carbide Sheets Research Articles

Impact of valley degeneracy on the thermoelectric properties of zig-zag graphene nanoribbons with staggered sublattice potentials and transverse electric fields.

This study investigates the band inversion of flat bands in zig-zag graphene nanoribbons (ZGNRs) using a tight-binding model. The band inversion results from symmetry breaking in the transverse direction, achievable through deposition on specific substrates such as separated silicon carbide or hexagonal boron nitride sheets. Upon band inversion, ZGNRs exhibit electronic structures characterized by valley degeneracy and band gap properties, which can be modulated by transverse electric fields. To explore the impact of this level degeneracy on thermoelectric properties, we employ Green's function techniques to calculate thermoelectric quantities in ZGNR segments with staggered sublattice potentials and transverse electric fields. Two carrier transport scenarios are considered: the chemical potential is positioned above and below the highest occupied molecular orbital. We analyze thermionic-assisted transport (TAT) and direct ballistic transport (DBT). Level degeneracy enhances the electric power factors of ZGNRs by increasing electrical conductance, while the Seebeck coefficient remains robust in the TAT scenario. Conversely, in DBT, the enhancement of the power factor primarily stems from improvements in the Seebeck coefficient at elevated temperatures.

Effect of the synthesis route and Co Coverage on Co / Ti3C2Tx materials for the oxygen evolution reaction

Green hydrogen resulting from water electrolysis is a key component for the transition to a renewable energy economy. However, it's success highly depends on active and stable electrocatalysts for the oxygen evolution reaction (OER) which is the bottleneck reaction of water electrolysis. Herein we assess the OER performance of non-noble metal-based electrocatalysts comprising Co oxide/hydroxide and delaminated 2D transition metal carbide sheets, Ti3C2Tx MXene. The catalytically active sites are provided by Co oxide/hydroxide, while the MXene contributes exceptional electrical conductivity. Our comprehensive electrochemical evaluation of their OER performance reveals that the chemical functionalization of Co on MXene sheets outperforms the pure Co or MXene alone, as well as physically mixed materials, across all tested performance metrics. From the materials characterisation, the chemical functionalized Co/Ti3C2Tx materials exhibit increased formation of layered double hydroxide (LDH) Co(OH)2 structures compared to the pure Co and physically mixed materials which may result in the improved OER activity observed for these materials. These findings emphasize the potential of anchoring transition metal oxides/hydroxides on MXene as a superior OER electrocatalyst for advancing sustainable green hydrogen production.

Titanium-doped graphite-type silicon carbide biosensor for detecting and eliminating gaseous pollution: A green chemistry approach by molecular simulation study

Regarding thermal strength, chemical stability and surface reactivity of silicon carbide (SiC), it is possible to allocate it as a suitable gas detector for commercial application. Therefore, this research was focused on the investigation of the chemo-resistivity properties of SiC nanosheet through doping with the transition metal. Thermochemical, electric and magnetic properties of titanium (Ti)-doped graphene-like monolayer silicon carbide (SiC) sheet have been studied by the first-principles methods based on the density functional theory (DFT) for scavenging of gas molecules of CO, CO2, NO, NO2. The results recommend that the adsorption of these gas molecules on Ti-embedded monolayer SiC sheet is more energetically desired than that on the pristine ones. Gas molecules of CO, CO2, NO, NO2 have been adsorbed on the Ti site of doped monolayer SiC through the formation of covalent bonds. The assumption of chemical adsorptions has been approved by the projected density of states (PDOS) and charge density difference plots. Charge density difference calculations also indicate that the electronic densities were mainly accumulated on the adsorbate of CO, CO2, NO, NO2 gas molecules. The results in this investigation can indicate the competence of transition metal doped silicon carbide nanosheet in sensor devices.

Tribological characteristics of nanofluid composite electrostatic spraying (NCES) in sliding friction

As a new improvement technology of minimum quantity lubrication (MQL), the tribological properties of nanofluid composite electrostatic spraying (NCES) are highly affected by type of base oil and adding location of nanoparticles. This work focused on the tribological characteristics of NCES with different base oils and adding locations (base oil, water, and both base oil and water) of muitiwall carbon nanotube (MWCNT) by sliding friction experiments with cemented carbide sheet and aluminum disc as the friction pair on the tribotest setup developed on the basis of lathe. The electrowettability of composite droplet was investigated and the effect mechanism of base oil type and adding location of MWCNT on tribological properties of NCES was discussed. The findings demonstrated that compared to NCES with castor oil as base oil, NCES with sunflower oil as base oil lowered the coefficient of friction and wear amount of cemented carbide sheet by 18.8–29.2% and 4.6–12.5%, respectively. In terms of tribological properties of NCES, the best adding location of MWCNT was both base oil and water, followed by base oil. NCES with accession of MWCNT in both sunflower oil and water exhibited the best tribological properties.

Si9C15 monolayer: A silicon carbide allotrope with remarkable physical properties

Zero band gap in graphene and silicene is an important obstacle to their application in nanodevices. Combining carbon and silicon atoms to form a silicon carbide (${\mathrm{Si}}_{x}{\mathrm{C}}_{y}$) sheet is an applicable proposal to solve the band gap issue. Very recently, a large-scale monolayer $\mathrm{Si}{}_{9}\mathrm{C}{}_{15}$ was successfully synthesized and exhibited suitable band gap and environment stability [Gao et al., Adv. Mater. 34, 2204779 (2022)]. Motivated by this recent experiment, we explore the electronic, mechanical, optical, and thermoelectric properties of a $\mathrm{Si}{}_{9}\mathrm{C}{}_{15}$ monolayer using first-principles calculations. Our results reveal that the monolayer is an auxetic material with a negative Poisson ratio of 0.175. The monolayer is a semiconductor with a direct band gap of 2.54 eV calculated by the Heyd-Scuseria-Ernzerhof functional (HSE06) functional. The optical properties of the monolayer are investigated by solving the Bethe-Salpeter equation. It is revealed that the optical band gap of the monolayer is 2.73 eV, and the exciton binding energy is equal to 1.14 eV, indicating a strongly bound bright exciton. Thermoelectric properties of the monolayer are calculated by combining density functional theory and Green's function formalism in the linear response regime. The lattice thermal conductance of the monolayer is 0.85 nW/K at room temperature, and the maximum figure of merit is 1.2 at 800 K, higher than that of other silicon carbide allotropes. High flexibility, a suitable band gap, high mobility, high optical absorption in the UV-visible region, and high thermoelectric efficiency make the $\mathrm{Si}{}_{9}\mathrm{C}{}_{15}$ monolayer a promising candidate for applications in mechanics, optoelectronics, and energy converters.

The crystallographic structure and properties of novel quaternary nanolaminated rare-earth-Cr-based i-MAX phases

Seven novel inherently nanolaminated transition metal carbides, (Cr2/3R1/3)2AlC (R = Gd, Tb, Dy, Ho, Er, Tm, Lu) with R in-plane chemical ordering in the carbide sheet, have been synthesized and found to be crystallized in Cmcm orthorhombic structure with monotonously decreased lattice parameters due to lanthanides constrictions. Linear antiferromagnetism is found for R = Gd and gradually changed to paramagnetism for R = Er, Tm and Lu through nonlinear magnetic configurations with gradually decreased ordering temperature. Compared with Cr2AlC benchmark, the Vickers hardness is significantly higher, leading to higher compressive fracture strength and better wear resistance. After compression at high temperature, nanoscale co-existence of the C2/c monoclinic and orthorhombic structure is observed, which is caused by the random stackings and high-density slidings within ab plane. The further first-principle calculations confirm the close thermal stability of both two structures.

Synthesis of vanadium carbide MXene with improved inter-layer spacing for SERS-based quantification of anti-cancer drugs

The development of rapid and efficient spectroanalytical protocols to detect bioactive drugs in aqueous samples is linked with the evolution of new generations of nanostructured materials. The 2D vanadium carbide (V2CTx) family of MXenes has been proved to be a promising material owing to its excellent plasmonic effects, short-range charge transfer (CT), and covers a wide variety of applications, especially in the fields of sensing and optics. For several years, research is focused on the stability and inter-layers spacing of a few-layered V2CTx in colloidal states. In this work, the synthesis and characterization of vanadium carbide sheets using a soft condition approach were reported. The delamination with the triethylamine (TEA) intercalant resulted in deceased interlayer spacing of 8.13 Å and enhanced the shelf life by up to six weeks. The synthesized highly stable MXene was treated with self-assembled silver nanoparticles (AgNPs) to fabricate a hybrid material as a potential surface-enhanced Raman scattering (SERS) substrate for the detection of ultra-trace quantities of anti-cancer drug gemcitabine (GMC). The developed approach showed an unprecedented limit of detection of 10-12 M with a wide dynamic range of 10-4-10-12 M. The MXene-based SERS sensor has achieved a Raman signal amplification corresponding to an enhancement factor of 109, with high sensitivity and reproducibility.

Corrosion behavior of new titanium alloys for medical applications

In this study, the ability of two titanium alloys to resist corrosion has been analyzed. This was accomplished by analyzing how the corrosion potential evolves with time as well as observing the Bode and Nyquist diagrams obtained with electrochemical impedance spectroscopy. The proportions of each alloy were A1 (94.4 % Ti, 4 % Mn, 0.6 % Al, 1 % Fe) and A2 (96.5 % Ti, 3 % Mn, 0.6 % Al, 0.2 % V). The two samples were covered in epoxy resin, cut in pieces, and polished using silicon carbide sheets of abrasive paper, the polishing was done progressively, using gradings from 280 to 1200 grit, ultimately using a 0.1 alpha alumina suspension for a last polish. Electrochemical tests were performed by immersing the polished samples in a Ringer Lactate solution. While the samples were immersed, they were connected to a saturated calomel electrode as reference electrode and to a platinum electrode acting as counter electrode. The two materials can resist to the effects of corrosion efficiently; initially it seemed that the alloy A1 improves its capacity to resist at corrosion when a positive potential is applied and loses it partially when a negative potential is applied. In alloy A2 the situation was similar but easier to observe, as when the supplied potential was too high or too low, the passivation of the material was not so good.

EFFECT OF MECHANICAL AND TRIBOLOGICAL PROPERTIES OF DIAMOND FILMS ON VARIOUS SUBSTRATES

Geological drilling required high-performance diamond drill bits. In this paper, diamond films were deposited on different drill bit substrates based on the MPCVD equipment. The properties of diamond films were analyzed by scanning electron microscopy (SEM), Raman spectra, X-ray diffraction (XRD) and tribological tests. The results showed that surface morphology of the four different substrates was good and the grain size was uniform. The diamond drill bit substrates include polycrystalline diamond compact (PDC), cemented carbide (WC–Co), impregnated diamond (IPD) and diamond thick-film welded (DT) sheets. The coefficients of friction of the deposited protective films are 0.15, 0.25, 0.23 and 0.29, respectively. What is more, the wear rates of protective films are [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text][Formula: see text]mm3/N[Formula: see text]m, respectively. Addition of diamond films could effectively reduce the friction coefficient on the surface and improve the service life of drill bit.

A precise electrochemical sensor based on Sm2O3/2D TiC hybrid for highly sensitive and selective detection of antihypertensive drug nimodipine

Hybridization of rare earth metal oxide with titanium carbide is a well-designed architecture for uses in sensing, energy conversion and storage, electronic devices, catalysis, and other applications. Herein to synthesized, a Sm2O3/2D TiC hybrid (samarium oxide/two-dimensional titanium carbide) using a facile hydrothermal process. The as-prepared hybrid was examined by various physicochemical techniques such as X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), Field emission scanning electron microscopy (FESEM) and High-resolution transmission electron microscopy (HRTEM). From, the morphology study to confirm the Sm2O3 flakes were successfully hybridized with titanium carbide sheet as a result to enhance the electrochemical active sites, low resistivity, and rapid ion transportation. Due to this behavior the modified Sm2O3/2D TiC/GCE has successfully detected antihypertensive drug nimodipine (NMP) by using CV (cyclic voltammetry), and DPV (differential pulse voltammetry) analysis. The Sm2O3/2D TiC/GCE sensor has demonstrated high sensitivity (1.5 µA µM−1 cm−2), a low LOD (4.2 nM), excellent repeatability, reproducibility, and storage stability. Particularly, Sm2O3/2D TiC/GCE was effectively used to detect NMP in biological samples and to obtain a well-acceptable result. We believe that, this Sm2O3/2D TiC hybrid electrocatalyst can act as a potential electrode material for the electrochemical detection of NMP in clinical biological applications.

Structural evolution of SiC sheet in a graphene-based in-plane hybrid system upon heating using molecular dynamics simulation

In-plane hybrid system containing graphene and silicon carbide (SiC) sheets (graphene-SiC-graphene) is studied via molecular dynamics simulation. The size of graphene sheets is 10,000 atoms/layer while the one of SiC sheet is 5700 atoms. The structural evolution of the SiC sheet in the graphene-SiC-graphene system is studied upon heating from 50 K to 3400 K via the Tersoff potentials. Some main results of the SiC sheet in the hybrid system are found, such as, the phase transition exhibits Devil's staircase type related to the SiC sheet from the fully in-plane graphene-SiC-graphene hybrid system, the phase transition initiates at temperature of 1750 K, the melting criterion is calculated (γ3=0.033) to classify the solid-like and the liquid-like atoms, the liquid-like atoms have tendency to form clusters. The formation of the clusters of the free-standing SiC and the SiC nanoribbon is also calculated to have an entire view about the influence of interactions at the boundaries on the formation of the clusters of SiC sheet in the hybrid system. The atomic mechanism of the phase transition from crystalline to liquid states is studied based on the radial distribution functions, the coordination number, and the angular distributions.

Probing and comparison of graphene, boron nitride and boron carbide nanosheets for Flutamide adsorption: A DFT computational study

The adsorption mechanism of Flutamide (FLU) anticancer drug on the surface of two-dimensional (2D) drug-delivery materials is studied in the gas phase and water media. In this study, we carried out density functional theory (DFT) calculation to survey the potential application of pristine graphene (GNs), hexagonal boron nitride (h-BN), and boron carbide (BC3) sheets as a substrate to carry and deliver drug molecule. The structural and electronic properties and also the adsorption energies of designed complexes are assessed. All adsorption and solvation energies are negative values that declare that all examined structures can be reliable and the synergistic effectsof the targeted molecule with the selected nanosheets are a spontaneous process. Optimized structures suggest that the most favorable adsorption site of FLU on the surface of the selected nanosheets is the parallel mode. By means of an AIM analysis, we receive the main and essential parameters such as the positive and negative measurements of Laplacian and total electron energy density properties, respectively, indicating that the nature of interaction in desired complexes is partially covalent. According to the NBO results, in the FLU/GNs and FLU/h-BN complexes, the charges are transferred from the GNs and h-BN nanosheets to the Flutamide molecule, while in the FLU/BC3 complexes, charge transfer occurs from the drug molecule to the BC3 sheet. To have a better chemically view of the reactions and stability of the obtained complexes, quantum molecular descriptors are calculated. It appears that the considered nanosheets can be employed as delivery systems for the drug to transfer FLU drug in the biological environment. Compared with selected nanosheets, BC3 nanosheet could be a more suitable candidate for delivering FLU drug within the biological systems.

A density functional theory study of electric, magnetic and optical properties of perfect and defected Germanium Carbide (GeC) sheet

In this paper, we use spin-polarized density functional theory (DFT) to study the electric, magnetic and optical properties of perfect and defected Germanium Carbide (GeC) sheets. We consider both mono vacancies (1C and 1Ge) and divacancies (1Ge-1C, 2C, and 2Ge). The optimized structure, formation energy, band structure, gap energy, projected density of states, the imaginary part of the dielectric tensor, electron density and the total magnetic moment are computed. Our results show that the formation energy of 1C is lower than the formation energy of 1Ge, meaning that 1C is a preferable defect. Also, 2Ge defect has the lowest formation energy in divacancies. According to band structure, perfect, 1C, 1Ge-1C, 2C and 2Ge are semiconductors while 1Ge is half-metal. The imaginary part of the dielectric tensors for perfect, 1Ge,1Ge-1C, 2C, and 2Ge show a peak near their gap energy thus transition between the valence band maximum (VBM) and conduction band minimum (CBM) is an allowed transition while for 1C is a forbidden transition. To study the magnetic properties, we plot the electron density for up spin (n↑), down spin (n↓) and n↑-n↓. We find that perfect, 1Ge-1C, 2C and 2Ge are non-magnetic (NM) while 1C and 1Ge are ferromagnetic (FM).

Bilateral Growth of Monoclinic Tungsten Oxide and 2D Ti3C2Tx-MXene on 3D Free-Standing Multilayer Hollow Graphene Foam for Flexible All-Solid-State Pseudocapacitor

To overcome the subordinate electrochemical performance of the pseudocapacitor, it is essential to design two-dimensional (2D) electroactive nanostructured material with enormous electroactive sites on the highly conductive current collector for enriching the rates of reversible charge transfer reactions. Herein, a scalable strategy was employed to prepare the electrodes by depositing pseudocapacitive materials on a three-dimensional (3D) free-standing highly conductive hollow multilayered graphene foam (HGF) synthesized through a template assisted-chemical vapor deposition (TA-CVD) method for the first time. The stable nanostructured monoclinic tungsten oxide (m-WO3) nanoparticles and 2D transition metal carbide (Ti3C2Tx-Mxene) sheets were bilaterally loaded on inner and outer sides of 3D HGF by a unipolar electrodeposition (UPED) method and a drop casting method, respectively. This free-standing electrode exhibited exceptional specific capacitance (Cs) of 487 F/g (439 mF/cm2) at 2 mA/cm2, outstanding rate performance and extraordinary cycling stability of 92.9 % over 5000 cycles owing to its significant metallic conductivity and reversible redox reactions of hydrophilic 2D Ti3C2Tx-Mxene. To assemble asymmetric pseudocapacitor, a MWCNT/RuO2 electrode with tiny RuO2 was also synthesized through a simple and inexpensive layer-by-layer (LBL) method. The obtained flexible asymmetric solid-state pseudocapacitor (FASC) illustrated 2-fold wider potential of 1.4 V in an acidic electrolyte when compared with Mxene based symmetric supercapacitor. This FASC displayed excellent Cs of 152.2 F/g at 5 mV/s, high energy density of 18 Wh/kg at 497 W/kg and an outstanding capacity retention of 93.3 % over 10000 GCD cycles with superb coulombic efficiencies of 99 ~ 100 %. In addition, the extraordinary demonstration performance of this FASC device by driving light emitting diodes (LEDs) and digital stopwatch signified its real-world applicability in electronic gadgets.

Two-dimensional hexagonal manganese carbide monolayer with intrinsic ferromagnetism and half-metallicity

Recent experimentally observed intrinsic ferromagnetism in two-dimensional (2D) van der Waals crystals has ignited substantial interests due to their great potential in spintronic devices. However, their practical applications are hampered by rather low Curie temperature and small magnetic anisotropic energy. Here, we predict from first-principles calculations that the 2D pristine hexagonal manganese carbide (h-MnC) sheet exhibits robust ferromagnetic and half-metallic features with complete spin polarization, sizable magnetic anisotropic energy, and wide half-metallic gap near the Fermi energy level. Moreover, the h-MnC sheet can retain its structure up to the temperature of 1000 K, indicating a highly thermodynamic stability. The Monte Carlo simulations based on the Heisenberg model with single-ion anisotropy predict a Curie temperature of 233 K in 2D h-MnC crystal. We confirm the robustness of the ferromagnetism and half-metallicity against the external strain from −6% to 10%. Also, a feasible experimental fabrication route is proposed to realize the h-MnC monolayer via heterostructure engineering and exfoliation techniques. Overall, the robustness of the half-metallicity in combination with the high-temperature ferromagnetism render the freestanding h-MnC monolayer and even its energetically favorable h-MnC/MoS2 and h-MnC/MoSe2 heterostructures quite promising materials for developing practical spintronic nanodevices.

Facile synthesis of colloidal nitrogen‐doped titanium carbide sheets with enhanced electrochemical performance

Facile synthesis of colloidal nitrogen‐doped titanium carbide sheets with enhanced electrochemical performance

Polydopamine intimate contacted two-dimensional/two-dimensional ultrathin nylon basement membrane supported RGO/PDA/MXene composite material for oil-water separation and dye removal

Titanium carbide (MXene) sheet membranes have become attractive candidates in terms of solvent nanofiltration performance. Whereas, the low contaminant removal ability limited the practical application of MXene membranes in efficient separation. Here, the reduced graphene oxide (RGO)/polydopamine (PDA)/titanium carbide (MXene) composites were prepared by dopamine modification method. Then, the RGO/PDA/MXene composites were suction filtrated on a nylon membrane to construct the two-dimensional-two-dimensional (2D-2D) laminated composite membrane. The effects of MXene content on the surface hydrophilicity, dye retention and oil-water separation properties of the modified membrane were systematically studied. Among them, the RPM-8 membrane exhibited ultra-high separation effect (>96%) and excellent throughput (>200 L/m2·h) for Methylene Blue (MB), Methyl Orange (MO), Methyl Red (MR), Congo Red (CO) and Evans Blue (EB). At the same time, the modified membrane shows very high oil-water separation effect on the emulsion (>97%). In addition, long-term cycle experiments have also revealed the stability of RGO/PDA/MXene composite membranes. The above results further illustrated the importance of the regular straight rigid channels of the composite membrane in separation performance. Therefore, RGO/PDA/MXene composite membrane has tremendous potential in practical applications.

Surface-Modified Two-Dimensional Titanium Carbide Sheets for Intrinsic Vibrational Signal-Retained Surface-Enhanced Raman Scattering with Ultrahigh Uniformity.

Surface-enhanced Raman scattering (SERS) employing a non-noble substrate in comparison with conventional noble-metal ones offers advantages of low cost and rich selection of candidates; however, its application has been seriously hindered by its unsatisfactory detection sensitivity, poor uniformity, and undesirable modification of vibrational signals via changing the orientation and/or polarizability of probe molecules. Here, an unusually sensitive but nonselective enhancement was achieved by employing titanium carbide sheets modified with aluminum oxyanions in situ as active supports for Raman measurement. The analyte molecules adopted a conformation similar to what they adopt on a bare substrate, while closely interacting with the aluminum oxyanion surface, which leads to the rare observation of highly sensitive but nonselective enhancement with a detection limit close to the pM level. With the substrate surface roughness in the nanometer region, an outstanding uniformity with a relative standard deviation of less than 4.3% was achieved. In addition, the SERS effect on the modified titanium carbide sheets was shown to be applicable to a wide range of analyte molecules, including both organic dyes and trace harmful compounds. The success of the work demonstrates the feasibility of surface tuning to improve the SERS effect, and it introduces a new window for two-dimensional materials in SERS applications.

High Thermal Conductivity Enhancement of Polymer Composites with Vertically Aligned Silicon Carbide Sheet Scaffolds.

Owing to the growth of demand for highly integrated electronic devices, high heat dissipation of thermal management materials is essential. Epoxy composites have been prepared with vertically aligned (VA) three-dimensional (3D)-structured SiC sheet scaffolds. The required VA-SiC sheet scaffolds were prepared by a novel approach starting with a graphene oxide (GO) scaffold. The VA-GO scaffolds were reduced to VA-graphene scaffolds in an argon environment, and the latter were subsequently transformed into VA-SiC sheet scaffolds by a template-assisted chemical vapor deposition method. Epoxy resin was filled in the empty spaces of the 3D scaffold of SiC sheets to prepare the composite mass. The material so prepared shows anisotropic thermal property with ultrahigh through-plane conductivity of 14.32 W·m-1·K-1 at a SiC sheet content of 3.71 vol %. A thermal percolation is observed at 1.78 vol % SiC filler. The SiC sheet scaffold of covalently interconnected SiC nanoparticles plays a vital role in the formation of the thermal conductive network to significantly enhance the thermal conductivity of epoxy composites. The application of the VA-SiC/epoxy composite as an efficient thermal dissipating material has also been presented. The VA-SiC/epoxy composites have a strong potential for preparing heat-dissipating components in integrated microelectronics.

Molecularly Thin Nitride Sheets Stabilized by Titanium Carbide as Efficient Bifunctional Electrocatalysts for Fiber-Shaped Rechargeable Zinc-Air Batteries.

With the ever-increasing growth in next-generation flexible and wearable electronics, fiber-shaped zinc-air batteries have attracted considerable attention due to their advantages of high energy density and low cost, though their development, however, has been seriously hampered by the unavailability of efficient electrocatalysts. In this work, we designed a trimetallic nitride electrocatalyst in an unusual molecular sheet form, which was stabilized by metallic titanium carbide sheets. Besides the expected elevation in catalytic activity toward the oxygen evolution reaction, the material simultaneously unlocked excellent catalytic activity for oxygen reduction reaction with the half-wave potential as small as 0.84 V. A flexible fiber-shaped zinc-air battery, employing the designed electrocatalyst as the air cathode and a gel as the electrolyte, demonstrated an enhanced and durable electrochemical performance, outputting a competitive energy density of 627 Wh kgzn-1. This work opens new avenues for utilizing two-dimensional sheets in future wearable and portable device applications.