Excess Vacancies Research Articles

Electric field/current enhanced grain growth behavior of 8mol% Y2O3 stabilized cubic ZrO2 (8Y-CSZ) polycrystals

The effect of the flash event on grain growth behavior was examined in 8 mol% yttria-stabilized cubic zirconia (8Y-CSZ) polycrystals under direct and alternating electric fields/currents. Even at the same specimen temperature, the rate of the grain growth is accelerated in the flash event than in the heat treatment without electric field/current (0 V), suggesting that the non-thermal effect caused additionally under the flash event contributes to the acceleration of the grain growth. Although the grain growth behavior can be characterized by the empirical equation (dtn –d0n = kt) with the same grain growth exponent of n = 3 irrespective of the electric field/current, the activation energy for the grain growth is lowered under the flash event. This suggests that the non-thermal effect caused by the flash event does not affect the mechanism of the grain growth, but would accelerate the rate-controlling process of the grain growth. The non-thermal effects can be further accelerated in fine-grained specimens under the alternating current flash and/or by increasing the input power density. Since the grain growth is rate-controlled by the grain boundary cation diffusivity, the non-thermal effect under the flash event would accelerate the grain boundary cation diffusivities through the formation of excess oxygen vacancies depending on the polarity and the power density.

Phase-field determination of NaSICON materials in the quaternary system Na2O-P2O5-SiO2-ZrO2: II. Glass-ceramics and the phantom of excessive vacancy formation

This work focuses on a very narrow region in the quaternary system Na2O-P2O5-SiO2-ZrO2 to explore the occasionally proposed deficiency in zirconium and oxygen content of Na+ super-ionic conductor (NaSICON) materials. In addition, this region is known for the formation of glass-ceramics, but a systematic study of such materials has not been carried out yet. For this purpose, 2 series of compositions were defined and synthesized: Na3.4Zr2-3x/4Si2.4-x/4P0.6+x/4O12-11x/8 and Na3.4Zr2-3x/4Si2.4+x/4P0.6+1.5x/4O12-x/16. They only differ in the silicate and phosphate content. In the first series the molar content is constant, nSi+ nP = 3. The latter series allows an excess of the 2 cations to meet the composition Na3.1Zr1.55Si2.3P0.7O11 or alternatively re-written as Na3.4Zr1.7Si2.52P0.77Ol2, which was formerly regarded as a superior material to the frequently reported composition Na3Zr2Si2POl2.Several characterization techniques were applied to better understand the relationships between phase formation, processing, and properties of the obtained glass ceramics in the context of the quasi-quaternary phase diagram. The investigations gave clear evidence that a glass phase is progressively formed with increasing x. Therefore, compounds with x > 0.2 have to be regarded as glass-ceramic composites. The resulting NaSICON materials revealed a very limited Zr deficiency with charge compensation by Na ions and a non-detectable amount of oxygen vacancies verified by neutron scattering and atomistic simulations.Hence, this work is the first systematic investigation of pretended Zr-deficient NaSICON materials, which clearly show the chemistry of a 2-phase region. The 2 investigated series are directed toward a region that is orthogonal to the series Na3Zr3-ySi2PyO11.5+y/2 reported in the first part of this series of publications.

Modulation of Sulfur Vacancies in ZnIn2S4/MXene Schottky Heterojunction Photocatalyst Promotes Hydrogen Evolution

AbstractThe sustainable production of hydrogen utilizing solar energy is a pivotal strategy for reducing reliance on fossil fuels. ZnIn2S4 (ZIS), as a typical metal sulfide semiconductor, has received extensive attention in photocatalysis. Although the introduction of sulfur (S) vacancies in ZIS to enhance photocatalytic hydrogen production by creating defect energy levels has been explored, detailed studies on the control and modulation of S‐vacancies in ZIS are sparce. This study demonstrates that while moderate levels of S‐vacancies can enhance hydrogen evolution, excessive vacancies may hinder the process, underscoring the importance of S‐vacancy modulation. Guided by theoretical calculations, We have designed and synthesized ZIS with modulated S‐vacancies to realize favorable hydrogen adsorption‐free energy and integrated in a Schottky‐heterojunction with MXene co‐catalysts for enhanced hydrogen evolution. The optimized hydrogen evolution performance of ZnIn2S4/MXene (ZMX) reaches 14.82 mmol g−1 h−1 under visible light irradiation, surpassing many reported ZnIn2S4‐based photocatalysts. The enhanced performance is ascribed to widened light absorption and enhanced carrier transportation realized by S‐vacancy modulation and the co‐catalytic effect. Femtosecond ultrafast absorption (fs‐TA) spectra and other in‐situ/ex‐situ characterizations further prove an efficient separation and transfer in an as‐prepared ZMX catalyst. These findings open up new perspectives for designing catalysts with vacancy modulation.

Effect of Iron Content on the Pitting Corrosion Behavior of Laser-Cladded Ni-Cr-Mo Alloy Coating in a Simulated Seawater Environment

In order to study the effect of iron content on the pitting corrosion behavior of a Ni-Cr-Mo alloy coating in a simulated seawater environment, a Ni-Cr-Mo-xFe (x = 0, 5, 10, 15, 20, 25) alloy coating was prepared through laser cladding technology. These coatings primarily consist of a γ-Ni solid solution phase, with observable iron segregation in the interdendritic regions when the iron content reaches 25 wt%. After 42 days of salt spray corrosion, it was found that pitting began to appear on the surface when the iron content in the coating increased to 10 wt%. The results of electrochemical behavior revealed that the coatings with iron contents in a range of 10–25 wt% exhibited metastable pitting characteristics, and the impedance modulus decreased with the increase in iron content. Pitting corrosion occurs due to selective corrosion of the dendritic regions. When the iron content exceeds 10 wt%, the accumulation of iron in the outer layer of the passivation film would lead to an excess of cationic vacancies, and the stability of the passive film is then reduced. This study provides a reference for the control of the iron content in a Ni-Cr-Mo alloy coating when applied in marine environments.

TRENDS OF CHANGES IN THE LABOR MARKET FOR GRADUATES OF IT SPECIALTIES AND EMPLOYMENT OPPORTUNITIES IN STACK 1C

Changes in the labor market are constantly occurring, and the IT specialist market is no exception. In this field, it is important to follow new trends in order to remain in demand as a specialist. In recent years, the demand for IT specialists has continued to grow, especially in the fields of software development, artificial intelligence, machine learning and cybersecurity. This opens up great opportunities for graduates of IT fields, especially in the light of universal digitalization and the transition to remote work. Currently, the market in the IT sector is striving for saturation, the offer of vacancies practically corresponds to demand. Employers are interested in mid- and high-level specialists. Applicants for IT professions require high salaries. For successful employment, you need to be a professional or go into scarce areas. The most in-demand and almost the only IT field where there is a shortage of specialists is 1C. The labor market in 1C is characterized by an excess of vacancies in relation to available resumes. A future specialist in this field should have skills in 1C programming, have knowledge in the subject areas of economics and continuously engage in their professional growth. Purpose – identification of trends in the labor market of IT specialties and employment prospects in the 1C stack. Methodology: the article used methods of analysis and synthesis of statistical information, methods of comparison and generalization. Results: the trend of increasing demand for 1C specialists in the labor market has been revealed. Practical implications it is advisable to apply the obtained results to enterprises, industries, municipalities, regions that monitor the labor market and the education system.

Highly responsive and selective NO gas sensing based on room temperature sputtered nanocrystalline WO3/Si thin films

This study investigates the nitric oxide (NO) gas sensing performance of room temperature sputtered nanocrystalline WO3 thin films deposited on Si substrate in a single step without heat treatment. The prepared WO3/Si sample properties have been systematically characterized for crystallographic, surface morphology, elemental, and chemical bonding analysis by XRD, FE-SEM, EDS, and XPS techniques, respectively. It has been observed that the thin film samples have a nanocrystalline structure with a granular-like porous morphology, and the presence of oxygen or metal vacancies/defects contributes to improving the sensing response of a target gas. The gas sensing performance of WO3 thin film deposited over Si (WO3/Si) has been recorded at various crucial parameters such as different operating temperatures (200–325 °C), gas concentrations (3–100 ppm), and target gases (H2S, CO, NH3, NO, and NO2). The maximum sensor response for 100 ppm concentration of NO gas was achieved at an operating temperature of 250 °C with a response time of ∼172 s and a recovery time of ∼86 s. At the optimal operating temperature of 250 °C, the lowest NO gas concentration was measured as low as 3 ppm. The calculated theoretical detection limit for NO gas at this concentration was determined to be 167 ppb. Further, the sample shows long-term stability over a period of 33 days and preserves the same value of sensor response. The selectivity performance tested for various gases clearly indicates that our sample is highly selective towards NO gas. This improved sensing performance can be attributed to the granular-like porous structure and excessive oxygen vacancies on the sample surface. The underlying sensing mechanism for superior response to NO gas has also been discussed. These results demonstrate the potential application of nanocrystalline WO3/Si thin film prepared at room temperature for the development of high-performance and cost-effective single-material-based metal oxide gas sensors.

Atom probe tomography-assisted kinetic assessment of spinodal decomposition in an Al-12.5 at.%Zn alloy

The rates of atomic clustering and precipitation hardening are closely related to the diffusivity of solutes and the concentration of vacancies during the natural aging of aluminum alloys. The measurement of the diffusivity of solutes at room temperature, especially in systems with an equilibrium vacancy concentration, is beneficial to the design of the aging process. However, this measurement has long been challenging because of the extremely low diffusion rates of solutes in aluminum at room temperature and the presence of supersaturated vacancies. In this work, we propose a method to quantify the diffusivity of solutes based on the kinetic evaluation of the spinodal decomposition process. This evaluation involves conducting atom probe tomography experiments, analyzing the radial distribution function, and modeling the phase separation process using the Cahn–Hilliard theory. The aging experiments were conducted on nanoscale samples, where excess vacancies can be eliminated at free surfaces due to a high surface-to-volume ratio. The results yielded a diffusivity of Zn in the Al-12.5 at.% Zn alloy of (1.32±0.46)×10−25 m2/s at 295 K. This work introduces a novel approach to assess the solute diffusivity under conditions of equilibrium vacancy concentration at room temperature and expands the temperature range for measuring the diffusivity in systems with spinodal decomposition, particularly in cases where kinetic data at low temperatures are scarce.

Recrystallization of bulk nanostructured magnesium alloy AZ31 after severe plastic deformation: an in situ diffraction study

The magnesium alloy AZ31, which has undergone high-pressure torsion processing, was subjected to in situ annealing microbeam synchrotron high-energy X-ray diffraction and compared to the as-received rolled sheet material that was investigated through in situ neutron diffraction. While the latter only exhibits thermal expansion and minor recovery, the nanostructured specimen displays a complex evolution, including recovery, strong recrystallization, phase transformations, and various regimes of grain growth. Nanometer-scale grain sizes, determined using Williamson–Hall analysis, exhibit seamless growth, aligning with the transition to larger grains, as assessed through the occupancy of single-grain reflections on the diffraction rings. The study uncovers strain anomalies resulting from thermal expansion, segregation of Al atoms, and the kinetics of vacancy creation and annihilation. Notably, a substantial number of excess vacancies were generated through high-pressure torsion and maintained for driving the recrystallization and forming highly activated volumes for diffusion and phase precipitation during heating. The unsystematic scatter observed in the Williamson–Hall plot indicates high dislocation densities following severe plastic deformation, which significantly decrease during recrystallization. Subsequently, dislocations reappear during grain growth, likely in response to torque gradients in larger grains. It is worth noting that the characteristics of unsystematic scatter differ for dislocations created at high and low temperatures, underscoring the strong temperature dependence of slip system activation.Graphical

Electronic structure and thermodynamic approaches to the prospect of super abundant vacancies in δ-Pu.

Super abundant vacancies (SAVs) have been suggested to form in the fcc phase of plutonium, δ-Pu, under a low-pressure hydrogen environment. Under these conditions, the vacancy concentration is proposed to reach 10-3 at% due to H trapping in vacancies lowering the effective vacancy formation energy. Previous density functional theory (DFT) results suggest that seven H atoms can be trapped in a single vacancy when a collinear special quasirandom magnetic structure is used to stabilize the δ phase, suggesting SAVs are a possible source of H stored in plutonium. In this report, we present DFT results for δ-Pu in the noncollinear 3Q magnetic state to study the formation of SAVs in mechanically stable δ-Pu. Together with these new simulations, we use publicly available computational and experimental data to provide further constraints on the physical conditions needed to thermodynamically stabilize SAVs in δ-Pu. Using several thermodynamic models, we estimate the vacancy concentrations in δ-Pu and discuss the limits of hydrogen driven formation of vacancies in δ-Pu. We find that, when hydrogen in the lattice is equilibrated with gaseous H2, the formation of SAVs in δ-Pu is unlikely and any excess vacancy concentration beyond thermal vacancies would need to occur by a different mechanism.

Modelling the spatial evolution of excess vacancies and its influence on age hardening behaviors in multicomponent aluminium alloys

Excess vacancies play crucial roles in the precipitation of age-hardening precipitates in aluminium alloys, but their spatial evolution across grains during heat treatments is less known. In this work, a numerical model is developed to predict the spatial evolution of non-equilibrium excess vacancies during cooling from solution treatment and during ageing heat treatments of multicomponent aluminium alloys. A finite volume scheme is applied to derive the spatial distribution of vacancy site fraction across grains by solving the diffusion equations of vacancies under the influence of solute elements. Binding energies between solute atoms and vacancies predicted by first-principles calculations has been used to handle the trapping of excess vacancies by solute atoms and atom clusters. The annihilation rates of excess vacancies at grain boundaries and at dislocation jogs have been derived based on a rigorous description of the annihilation mechanisms of vacancies. The evolution of the density of dislocation jogs due to vacancy annihilation has been taken into account. The model is successfully applied to interpret the age hardening behaviors of experimental alloys subjected to different thermomechanical processing conditions. This model will help to reach a deeper understanding of the roles of excess vacancies in precipitation kinetics and therefore is important to further optimize thermomechanical processing parameters and alloy composition to improve the macroscopic mechanical properties of age hardening aluminium alloys.

Oxygen vacancies modulated Co3O4 toward highly efficient electrooxidation of 5-hydroxymethylfurfural

Electrochemical oxidation of 5-hydroxymethylfurfural (HMF) has emerged as a promising method to produce highly valuable chemicals. Co-based electrocatalysts with oxygen vacancies are one of the most promising candidates. However, the relationship between their electrocatalytic behavior and the vacancy concentration is still ambiguous. In this work, the diverse oxygen vacancy contents of Co3O4 were realized via a simple adsorption-pyrolysis method and confirmed by X-ray diffraction, Raman, transmission electron microscopy, X-ray photoelectron spectroscopy and X-ray absorption spectroscopy, respectively. It was found that the Co3O4 with proper oxygen vacancies prepared at optimized conditions exhibits a superior catalytic activity for HMF oxidation reaction (HMFOR) in 1.0 M KOH with 50 mM HMF electrolyte (with the potential of 1.35 V vs. RHE at 10 mA cm−2). Correlational characterizations and density functional theory calculations demonstrate that appropriate oxygen vacancies can promote HMF electrooxidation performance, whereas excessive oxygen vacancies can hinder electron transport and result in a significant decline in HMF electrooxidation performance. This study reveals the significance of appropriate oxygen vacancies in catalytic oxidation activity and provides important insights into the role of oxygen vacancies in catalytic oxidation reactions for the synthesis of defective material.

Modeling the Effect of Excess Vacancies on Precipitation and Mechanical Properties of Al–Mg–Si Alloys

A model for vacancy annihilation during aging has been combined with a precipitation model for coupled nucleation, growth, and coarsening in AA 6xxx series aluminum alloys. The simulation results were compared with precipitation parameters from TEM measurements and hardness data obtained for various times during artificial aging. Both simulations and measurements indicated that a combination of an excess concentration of non-equilibrium vacancies at the start of aging and a fast vacancy annihilation rate significantly affected the resulting precipitation and strength evolution. Hence, the model reproduced the short aging time required to reach the maximum strength when direct artificial aging was applied (DAA). In contrast to the fast aging response of DAA, the hardness measurements showed a much slower aging response when artificial aging was performed after prolonged natural aging. This aging behavior was captured in the model simulations by assuming that an equilibrium vacancy concentration is present from the start of the aging.

Strain-induced clustering in Al alloys

Solute clusters represent the start of decomposition during aging of aluminum alloys and can generate strengthening while keeping the strain hardening high in comparison with shearable precipitates. In this study, clusters in a pre-aged AlMgSiCu 6xxx-series and a recently developed AlMgZnCu crossover alloy were investigated by atom probe tomography (APT) and tensile testing before and after straining. Pre-aging was performed at 100 °C and 60 °C respectively, and a tensile strain of 5% was applied. The key feature detected was the formation of clusters during plastic deformation, referred to here as “strain-induced clustering”. It is explained based on diffusion enhancement by the strain-induced formation of excess vacancies during tensile testing, and evaluated by means of a simple modeling approach. In addition to the significant intrinsic contribution of clusters to strain hardening via dislocations, strain-induced clustering adds a hypothetical non-dislocation-based component to strain hardening.

Symmetric bipolar resistive switching in copper oxide nanostructure/ITO lateral device under exposure to atmospheric oxygen and application in artificial synaptic devices

Capacitively coupled resistive switching behaviour was observed in a planar-geometry two-terminal device based on nanostructures of copper oxide as active material and indium tin oxide (ITO) as electrodes. When tested in ambient atmosphere, current-voltage I−V characteristic was found to be symmetric with pronounced hysteresis loop signifying two different states of resistance, namely the low resistive state (LRS) and high resistive state (HRS). Capacitive effect was apparent in the low voltage regime due to the presence of offset voltage at zero current and offset current at zero bias. X-ray photoelectron spectroscopy (XPS) analysis confirmed the presence of native oxygen vacancies in copper oxide. Additionally, exposure to atmospheric oxygen played the dominant role in creation of excess vacancy sites by electrochemical reaction near positive electrode. Creation of excess density of oxygen vacancy near the electrodes in conjunction with trapping and detrapping of electrons from these defect sites is perceived as the prime mechanism for the observed switching behaviour. The device ON/OFF ratio, ION/IOFF∼1.5 was found to be stable over at least 100 continuous cycles. When tested under vacuum, the device I−V characteristics was linear in shape without any hysteresis signifying ohmic transport. Analysis of ultraviolet photoelectron spectroscopy (UPS) showed the Fermi energy level of copper oxide is at ∼ 4.69 eV, which is in a close match with the work function of ITO-electrode. The essential synaptic characteristics such as learning and forgetting curves and paired pulse facilitation (PPF) are established. The nonlinearity factors (NLF) are very low indicating the copper oxide-based devices are promising candidates for neuromorphic applications.

Design of Merchandise Inventory Accounting System at PT. Abdi Karya Kotamobagu

A well-designed accounting system will provide good benefits for management in managing its business. PT. Abdi Karya Kotamobagu is a company operating in the supermarket sector. The aim of this research is to design an inventory accounting system at PT. Abdi Karya Kotamobagu. The research results show that PT. Abdi Karya Kotamobagu has an inventory accounting system that supports company operations, but there are still several problems such as loss of merchandise caused by several parties or incomplete goods received from distributors due to the warehouse not checking the goods received, shortages and excess inventory and vacancies. merchandise inventory. This happens because the documents used regarding inventory have not been designed properly, there is no inventory card function and physical counting system.

Comprehensive understanding on phosphorus precipitation in heavily phosphorus-doped Czochralski silicon

Heavily phosphorus-doped Czochralski (HP-CZ) silicon is an important substrate material for manufacturing power electronic devices. The high concentration of phosphorus impurities may be supersaturated during the crystal growth of HP-CZ silicon or device manufacturing. Thus, understanding phosphorus precipitation in HP-CZ silicon is of technological significance. Herein, a panoramic view of phosphorus precipitation in HP-CZ silicon is presented in terms of crystallography, thermodynamics, and kinetics. It is found that the orthorhombic SiP precipitates can form during the crystal growth of HP-CZ silicon and also during the post-anneals of HP-CZ silicon at 450–1050 °C. Along with increasing annealing temperature, the formed SiP precipitates tend to adopt the platelet, polyhedron, and sphere-like shapes. Moreover, the excess point defects, i.e., silicon self-interstitials and vacancies, are found to affect phosphorus precipitation occurring in the low and high temperature regimes in different ways. In light of the kinetics of phosphorus precipitation at different temperatures, it is deduced that phosphorus precipitation follows a growth law in compliant with Ham's theory to a large extent. As an important output of this work, the temperature-dependent phosphorus solubilities in the dislocation-free silicon, which have been hardly acquired previously, are derived on the basis of investigating phosphorus precipitation in a set of HP-CZ silicon wafers with different phosphorus concentrations. Moreover, the derived solvus line for the phosphorus impurities in silicon could be a beneficial supplement to the existing phase diagram of the Si–P binary system in the extremely silicon-rich corner.

On the oxygen vacancy annealing in air plasma sprayed yttria‐stabilized zirconia thermal barrier coatings

AbstractYttria‐stabilized zirconia (t’‐YSZ) thermal barrier coatings (TBCs) were deposited by air plasma spraying (APS) using commercial purity and high‐purity feedstock powders. The coatings were subjected to short‐term, low‐temperature annealing (500–1200°C for 30 min). Significant structural changes were observed by X‐ray diffraction and Raman spectroscopy. These changes were attributed to annihilation of excess oxygen vacancies created by the process. APS induces partial reduction of YSZ due to the reducing potential of the high‐temperature and hydrogen‐rich plasma environment. Laser flash thermal conductivity, impulse excitation elastic modulus, and dilatometric measurements show significant changes in the YSZ during the short‐term low‐temperature thermal exposure, concurrent to the vacancy annealing. The results were analyzed in terms of the coating chemistry and the processing environment. High‐purity coatings exhibited larger increment in thermal conductivity and elastic modulus than commercial purity coatings.

In-situ investigation of dynamic precipitation in pre-aged Al-Zn-Mg-Cu alloy AA7075

High strength Al-Zn-Mg-Cu alloys rely for their properties on nano-scaled precipitates formed during artificial ageing. Deformation profoundly affects the evolution of these precipitates. This study investigates the effect of warm deformation on precipitation in a pre-aged AA7075 aluminium alloy. Warm deformation was performed using an electro-thermomechanical testing machine for rapid resistance heating. Transmission electron microscopy showed slightly larger, yet evenly distributed, precipitates in the warm deformed sample compared to the thermally treated condition without deformation. Synchrotron small angle X-ray scattering revealed accelerated growth rates of precipitates due to deformation. At low plastic strains, the growth rate increased linearly with applied strain, while at high plastic strains, a slight deviation from linear behaviour was observed. Temperature and strain rate effects were also examined, with a stronger enhancement effect at low temperature and fast strain rate for a given strain. The deformation enhancement effect disappeared rapidly upon finishing plastic deformation (within 400 s for the studied condition). The enhanced growth rate during and after deformation can be reasonably explained by the excess vacancy concentration, indicating the influence of strain-induced excess vacancies. However, the simple excess vacancy model used fails to explain the observed strain rate effect, and possible explanations for this discrepancy are discussed.

In Situ Heating Positron Annihilation Lifetime Spectroscopy Experiments on an Al–Mg Alloy

The binding between vacancies and Mg atoms in an aluminum solid solution is not fully understood but essential for understanding its role in age hardening of many Al alloys. After annealing and quenching, Mg prevents the loss of excess vacancies during natural ageing and forms complexes containing one, possibly two, vacancies, and various Mg atoms. By heating the alloy after natural ageing, these complexes are dissolved, i.e., natural ageing is reverted. This reversion process is studied by in situ positron annihilation lifetime spectroscopy utilizing the very high count rate at the accelerator driven facility ELBE. Positron spectra are continuously acquired during heating at rates between 3 and 50 K min−1. After correcting for the contributions of the oxidized surface and decomposing spectra into components, the process can be followed in detail and is found to take place in distinct stages: first, the number of vacancy–Mg complexes is reduced and then the liberated vacancies agglomerate into clusters that eventually dissolve at even higher temperatures.

Grapefruit juice containing rich hydroxyl and oxygenated groups capable of transforming 1D structure of NiCo2O4 into 0D with excessive surface vacancies for promising energy conversion and storage applications

Fabrication of an efficient electrode material is highly demanded for obtaining high energy conversion electrochemical system. In this study, we describe a green and innovative approach of using grape fruit juice as a high carrier of reducing and surface modifying agents for manipulating the surface properties of nickel‑cobalt bimetallic oxide NiCo2O4 nanostructures. Different amounts of grape fruit juice were used to discern its role on the morphological and surface vacancies of NiCo2O4 nanostructures during oxygen evolution reaction (OER). Importantly, the physical characterization revealed the morphological transformation of NiCo2O4 nanostructures from 1D nanorods to short range 0D nanoparticles. Furthermore, the surface studies have shown that NiCo2O4 nanostructures prepared with grapefruit juice have high density of surface vacancies and higher amount of Ni2+ and a Co2+ metallic ions on the surface of NiCo2O4 compare to pure NiCo2O4 nanostructures. The OER of electrodes modified with NiCo2O4 nanostructures, particularly (sample-2, 2 mL of grape fruit juice) gave rise to an overpotential value of 260 mV at 10 mAcm−2 in 1.0 M KOH aqueous solution along with high durability/stability for 40 h. Additionally, the obtained electrochemical impedance spectroscopy value of 80 Ω and active surface area of 18.1 μFcm−2 attested for the excellent OER performance of NiCo2O4 nanostructures (sample-2). Eventually, the proven enhancement in surface vacancies, alternation in the mixed oxidation states of both Ni and Co together with the morphological transformation that have been accomplished via the green, simple, and low-cost strategy of using grape juice make it a suitable option for large scale production of wide range of multifunctional metal oxides and related nanostructured materials for plethora of energy conversion and storage applications.