ZnCo2O4 Research Articles

Spinel cobalt-based binary metal oxides as emerging materials for energy harvesting devices: synthesis, characterization and synchrotron radiation-enabled investigation.

The synthesis and characterization of spinel cobalt-based metal oxides (MCo2O4) with varying 3d-transition metal ions (Ni, Fe, Cu, and Zn) were explored using a hydrothermal process (140 °C for two hours) to be used as alternative counter electrodes for Pt-free dye-sensitized solar cells (DSSCs). Scanning electron microscopy (SEM) and atomic force microscopy (AFM) revealed distinct morphologies for each metal oxide, such as NiCo2O4 nanosheets, Cu Co2O4 nanoleaves, Fe Co2O4 diamond-like, and Zn Co2O4 hexagonal-like structures. The X-ray diffraction analysis confirmed the cubic spinel structure for the prepared MCo2O4 films. The functional groups of MCo2O4 materials were recognized in metal oxides throughout Fourier transform infrared (FTIR) analysis. The local structure analysis using X-ray absorption fine structure (XAFS) at Fe and Co K-edge identified octahedral (Oh) Co3+ and tetrahedral (Td) Co2+ coordination, with Zn2+ and Cu2+ favoring Td sites, while Ni3+ and Fe3+ preferred Oh active sites. Further investigations utilizing the Fourier transformation (FT) analysis showed comparable coordination numbers and interatomic distances ranked as Co-Cu > Co-Fe > Zn-Co > Co-Ni. Furthermore, the utilization of MCo2O4 thin films as counter electrodes in DSSC fabrication showed promising results. Notably, solar cells based on CuCo2O4 and ZnCo2O4 counter electrodes showed 1.9% and 1.13% power conversion efficiency, respectively. These findings indicate the potential of employing these binary metal oxides for efficient and cost-effective photovoltaic device production.

Asymmetric Supercapacitors Based on ZnCo2O4 Nanohexagons and Orange Peel Derived Activated Carbon Electrodes.

Herein, the performance of asymmetric supercapacitors (ASC) fabricated using ZnCo2O4 (ZCO) nano-hexagons and orange peel-derived activated carbon (OPAC) as electrodes was studied. ZCO was prepared by a double hydroxide method and OPAC was prepared from orange peel followed by KOH activation. For ZCO, the calcination temperature was determined using TGA analysis. The XRD showed the presence of a cubic spinel structure. The chemical structure was analyzed using XPS, FTIR, and Raman spectroscopy respectively. For OPAC, the presence of an amorphous nature was inferred; FTIR and Raman studies indicate the presence of functional groups and defect structure in the material. The presence of ZCO nano-hexagons was observed from SEM and TEM respectively. For OPAC, an interconnected pore structure was observed from the SEM image. The specific capacitance for ZCO and OPAC was found to be 194 F.g-1 and 159 F.g-1 at a current density of 0.25 A.g-1. Further, an ASC was fabricated using ZCO as a positive and OPAC as a negative electrode in 2M KOH-soaked separator. A cell voltage of 1.2 V was achieved and the specific capacitance was calculated to be 64 F.g-1 at 0.25 A.g-1. Further, the cyclic stability and the changes at the electrode/electrolyte interface were studied.

Mesoporous Mn-substituted MnxZn1-xCo2O4 ternary spinel microspheres with enhanced electrochemical performance for supercapacitor applications.

Extensive investigations have been carried out on spinel mixed transition metal oxide-based materials for high-performance electrochemical energy storage applications. In this study, mesoporous Mn-substituted MnxZn1-xCo2O4 (ZMC) ternary oxide microspheres (x = 0, 0.3, 0.5, 0.7, and 1) were fabricated as electrode materials for supercapacitors through a facile coprecipitation method. Electron microscopy analysis revealed the formation of microspheres comprising interconnected aggregates of nanoparticles. Furthermore, the substitution of Mn into ZnCo2O4 significantly improved the surface area of the synthesized samples. The electrochemical test results demonstrate that the ZMC3 oxide microspheres with an optimal Mn substitution exhibited enhanced performance, displaying the largest specific capacitance of 589.9Fg-1 at 1Ag-1. Additionally, the ZMC3 electrode maintained a capacitance retention of 92.1% after 1000 cycles and exhibited a significant rate capability at a current density of 10Ag-1. This improved performance can be ascribed to the synergistic effects of multiple metals resulting from Mn substitution, along with an increase in the surface area, which tailors the redox behavior of ZnCo2O4 (ZC) and facilitates charge transfer. These findings indicate that the incorporation of Mn into mixed transition metal oxides holds promise as an effective strategy for designing high-performance electrodes for energy storage applications.

Surface‐Modified ZnCo2O4 Nanoparticles as Binder‐Free Electrode for All Solid‐State Asymmetric Supercapacitor

AbstractChoice of electrode material is crucial to the development of high‐performance supercapacitors. Since surface properties are key to the performance of an electrode material for supercapacitors, surface chemical treatment of electrode materials is an interesting topic of research. ZnCo2O4 (ZCO) is a low‐cost binary transition metal oxide with high theoretical conductivity and charge storage capacity making it a good choice for supercapacitor electrode. Herein, we present a systematic investigation of the influence of four different surface modifier (3 surfactants, 1 mineralizer) on ZCO electrode directly grown on Ni foam to compare the relative influence on the performance of the modified ZCO electrode. Analyses of the modified ZCO electrodes revealed the formation of cubic spinel phase of ZCO with average particle size of ~30 nm. The sodium dodecyl sulfate (ZCO−S) modified electrode (ZCO−S) exhibited the best electrochemical performance with specific capacitance of 1988 F/g at 1 A/g and 87 % capacity retention after 7000 cycles at 10 A/g. Further, an all‐solid‐state asymmetric supercapacitor (ASC) was fabricated with ZCO−S on Ni foam and carbon nanotube combination which exhibited specific capacitance of 102 F/g at 1 A/g corresponding to power density of ~1599 W‐kg−1 establishing ZCO−S as a very good electrode material for supercapacitor.

Nitrogen-doped reduced graphene oxide enfolded zinc cobaltite micro flowers as efficient triiodide reduction for a platinum-free counter electrode in dye-sensitized solar cell applications

Diverse varieties of organic and inorganic materials have been employed as counter electrodes (CEs) in dye-sensitized solar cell applications (DSSCs) to replace platinum (Pt). Interestingly, the influence of N-doped reduced graphene oxide on ZnCo2O4 with high surface area, superior electrical activity, and chemical stability has been addressed in this work. Pure ZnCo2O4 (ZCO), ZnCo2O4/reduced graphene oxide (rGO) (ZCOG), and ZnCo2O4/nitrogen-doped reduced graphene oxide (N-rGO) (ZCONG) had synthesized using a facile hydrothermal technique, and their performance as a CE material in DSSC application was further investigated. The formation of the material free of impurities is depicted by X-Ray Diffraction (XRD) and Raman analysis. The analysis utilizing Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) confirmed the existence of ZnCo2O4 micro flowers made of rods and sheets as well as the thin sheet-like shape of graphene oxide (GO) and N-rGO. The X-ray photoelectron spectroscopy (XPS) analysis technique was employed to determine the chemical composition and purity of the prepared samples. Further, the BET analysis confirms the higher specific surface area (1198.431 m2/g) of the ZCONG sample. The electrochemical property of the coated CEs was investigated using cyclic voltammetry (CV) analysis with the iodine-based electrolyte in a three-electrode system showing superior catalytic properties of the ZCONG CE than the other ZCO and ZCOG CEs. The as-fabricated CEs were utilized to assemble the DSSC device, and the ZCONG CE reached a photovoltaic power conversion efficiency (PCE) of 5.84 ± 0.06%, surpassing ZCO (3.51 ± 0.15 %) and ZCOG (4.81 ± 0.08 %) CEs.

Anchoring Polydopamine on ZnCo2 O4 Nanowire To Facilitate Urea Water Electrolysis.

To overcome the sluggishness of the oxygen evolution reaction (OER), the urea oxidation reaction was developed. In the case of OER application studies ZnCo2 O4 is an excellent electrocatalyst, towards the UOR has been performed with surface-grown polydopamine (PDA) with surface-grown polydopamine (PDA). ZnCo2 O4 @PDA is produced over the surface of nickel foam by a hydrothermal method followed by self-polymerization of dopamine hydrochloride. Dopamine hydrochloride was varied in solution to study the optimal growth of PDA necessary to enhance the electrochemical activity. Prepared ZnCo2 O4 @PDA was characterized by X-ray diffraction, electronic structural, and morphology/microstructure studies. With successful confirmation, the developed electrode material was applied to UOR and ZnCo2 O4 @PDA-1.5, delivering an excellent low overpotential of 80 mV at 20 mA cm-2 in the electrolyte mixture of 1 M potassium hydroxide+0.33 M urea. To support the excellent UOR activity, other electrochemical properties such as the Tafel slope, electrochemical surface active sites, and electrochemical impedance spectroscopy were also studied. Furthermore, a schematic illustration explaining the UOR mechanism is shown to allow a clear understanding of the obtained electrochemical activity. Finally, urea water electrolysis was carried out in a two-electrode symmetrical cell and compared with water electrolysis. This clearly showed the potential of the developed material for efficient electrochemical hydrogen production.

Sol-Gel Prepared Spinel HTLs for Assembling 20% Efficiency Perovskite Solar Cell in Air Without Using Anti-Solvent and Toxic Solvent.

Low-temperature sol-gel prepared ZnCo2 O4 spinel-based thin films are developed as high-performance hole transporting layer (HTL) for coating perovskite film (NA-Psk) from the basic MAPbI3 /ACN/CH3 NH2 solution in air without using anti-solvent. Inverted PSC based on 2mole% (vs Zn) Cu2+ doped ZnCo2 O4 (2%Cu@ZnCo2 O4 ) HTL and NA-Psk absorber exhibit the maximum power conversion efficiency (PCE) of 20.0% with no current hysteresis while the cell based on ZnCo2 O4 and PEDOT:PSS HTL (using NA-Psk absorber) achieves the PCE of 15.79% and 12.3% with a current hysteresis index of 9.8% and 32.4%, respectively. Without encapsulation, PSCs based on 2%Cu@ZnCo2 O4 , ZnCo2 O4 , and PEDOT:PSS HTLs maintain 90%, 77%, and 12%, respectively of the original efficiency by standing in ambient atmosphere (temperature: 20-25°C, RH:30%-40%) for 1800h. Large area (10cm× 10cm substrate) perovskite mini-module (PSM) with PCE over 15% is also demonstrated by using sol-gel prepared 2%Cu@ZnCo2 O4 HTL. The poor photovoltaic performance of PEDOT:PSS HTL is due to the basic MAPbI3 /ACN/CH3 NH2 solution will deprotonate the acidic PEDOT:PSS to reduce its conductivity whereas ZnCo2 O4 HTL are not affected by basic perovskite precursor solution.

Activating Lattice Oxygen in Spinel ZnCo2O4 through Filling the Oxygen Vacancies with Fluorine for Electrocatalytic Oxygen Evolution.

The development of productive catalysts for oxygen evolution reaction (OER) remains a major challenge that requires significant progress in both mechanism and material design. Conventionally, the thermodynamic barrier of the lattice oxidation mechanism (LOM) is lower than that of absorbate evolution mechanism (AEM) because the former could bypass certain limitations. However, it remains a challenging task to control the OER pathway from the AEM to the LOM by taking advantage of the intrinsic properties of catalyst. Herein, we incorporate F anion into oxygen vacancies of spinel ZnCo2O4 and establish the link between electronic structure and the OER catalytic mechanism. Density theoretical calculation reveals that F upshifts O 2p center and activate the redox capability of the lattice O, successfully triggering the LOM pathway, achieving a low overpotential of 350 mV at 10 mA cm-2. Moreover, the large electronegativity of F anion is favorable for the balance of residual protonation, which can stabilize the structure and locally trigger LOM without surface reconstruction during OER reaction. This finding provides a feasible strategy to concurrently enhance the activity and stability of OER, and demonstrates the significance of considering lattice oxygen participation for understanding the OER trend of highly active spinel.

The Polysulfide-Cathode Binding Energy Landscape for Lithium Sulfide Growth in Lithium-Sulfur Batteries.

A cathode substrate with strong adsorption of lithium polysulfides (LiPSs) has been preferred for lithium-sulfur(Li-S) batteries. However, the recent finding that controlled growth of lithiumsulfides(Li2 S) during discharge is crucial forS utilization stimulates improvement of this preference. Here, the Li2 S growth and cell capacity in the LiPS binding energy landscape of cathode substrates are investigated. Specifically, Co-based ternary oxides are employed to obtain binding energies in the range of 4.0-7.4eV. Of these substrates, only the MnCo2 O4 substrate with moderate LiPS affinity exhibits 3D Li2 S growth. The MnCo2 O4 cells achieve high sulfur utilization up to 84% at 0.2C and excellent performance even under high sulfur loading/lean electrolyte conditions. In contrast, weak affinity substrates such as ZnCo2 O4 and strong affinity substrates such as NiCo2 O4 and CuCo2 O4 exhibit low discharge capacity with 2D Li2 S growth. For optimal LiPS affinity driving 3D growth, a balance between promoting LiPS adsorption and diffusion limitation in the LiPS adsorption layer is suggested.

Tailoring the electronic structure of ZnCo2O4 by incorporating anions with low electronegativity to improve the water oxidation activity

Electron configurations and conductivity are significant descriptors/characteristics for the oxygen evolution reaction (OER), which can be modulated with heteroatom doping. Given that metal substitution usually reduces the number of active sites of spinel electrocatalysts, the effect of anion doping on the electronic structure has been investigated by using ZnCo2O4 (ZCO) as a demonstration. Compared with Co3+-dominated ZCO, the substitution of oxygen with less electronegative sulfur raises the portion of Co2+ in the low-spin states (t2g6eg1), which is more OER-active than Co3+ (t2g6eg0). Co2+ in the sulfur-doped ZCO (ZCO-S) is associated with the redistribution of electron density from S toward Co due to the high covalent interaction of Co—S. The Co—S interaction also induces a fast charge transfer. ZCO-S outperforms pristine ZCO by 11 times in terms of specific OER activity at 1.65 V versus reversible hydrogen electrode. In contrast, doping fluorine with higher electronegativity and valence deteriorates OER activity. Our work establishes the correlation between the electronegativity of anion dopants and OER intrinsic activity in spinel oxides and provides a simple and effective method to modulate the electronic structure of spinel oxides by doping anions with different electronegativities, which can be a new avenue for the rational design of high-performance spinel electrocatalysts.

A Pseudocapacitor Diode Based on Ion-Selective Surface Redox Effect.

Supercapacitor diode (CAPode) is a novel device that integrates ion diode functionality into a conventional electrical double-layer capacitor and is expected to have great applications in emerging fields such as signal propagation, microcircuit rectification, logic operations, and neuromorphology. Here, a brand new pseudocapacitor diode is reported that has both high charge storage (50.2Cg-1 at 20mVs-1 ) and high rectification (the rectification ratio of 0.79 at 200mVs-1 ) properties, which is realized by the ion-selective surface redox reaction of spinel ZnCo2 O4 in aqueous alkaline electrolyte. Furthermore, an application of the integrated device is demonstrated in the logic gate of circuit system to realize the logic operations of "AND" and "OR". This work not only expands the types of CAPodes, but also provides a train of thought for constructing high-performance capacitive ionic diodes.

A facile method for synthesizing MOF derived ZnCo2O4 particles on MXene nanosheets as a novel anode material for high performance hybrid supercapacitors

MXene (MX) is a capable material for future generation supercapacitor devices. But, the attraction between active functional groups and hydrogen bonds on the surface of MX make the interlayer agglomerate obviously. In this work, we present a ZnCo-MOF (ZCM) derived ZnCo2O4 (ZCO) particles to adsorb on the (MX) nanosheets and form a mesoporous structure which may provide the flexible ion diffusion pathways. The as obtained MXene@ZnCo2O4 (MX@ZCO) composite is investigated using XRD, XPS, HRTEM, FESEM, and nitrogen adsorption and desorption isotherm analysis. The ZCO particles not only provide activation sites for free movement of charges but also help to avoid the agglomeration of MX nanosheets. Benefitted from this novel composite structure, MX@ZCO holds a great specific capacity of 260 mAh g−1 at the current density of 1 mA g−1. Further, the MX@ZCO electrode exhibits a good cyclic stability of 78.9% even after 5000 cycles at the current density of 10 mA g−1, which can be ascribed to excellent electronic conductivity and short ion transport path. Furthermore, the fabricated aqueous HSC device with MX@ZCO/NF as a positive electrode and AC/NF as a negative electrode revealed a high energy density of 63.8 Wh kg−1 at power density of 3512.2 W kg−1, along with the outstanding capacitance retention of 91.3% even after 15,000 GCD cycles. This work offers an excellent approach for the preparation of MX and ZCO composite material as an electrode for hybrid supercapacitors.

Redox mediator-enhanced charge storage in dimensionally tailored nanostructures towards flexible hybrid solid-state supercapacitors.

Although extensive research has been performed on metal oxide-based supercapacitors during recent years, they remain lacking in their intrinsic conductivity and stability. To resolve this, 1D/2D heterostructure materials are being utilized, which significantly improves the performance and stability of both materials while employing their synergistic advantage consisting of morphologically tuned surfaces and superior electroactive sites. However, the performance remains unsatisfactory due to the sluggish faradaic reaction at the electrode/electrolyte interface. To address this challenge, we combined the synergistic advantage of morphological nanoengineering and the fast reaction kinetics of redox mediators, thus anticipating superior energy storage performance. A novel 1D/2D heterostructure of ZnCo2O4 (ZCO) and GaN was designed and implemented for the first time, and it demonstrated an excellent specific capacitance of 1693 F g-1 in the mixed electrolyte of KOH and K4[Fe(CN)6]. The all-solid-state flexible hybrid supercapacitor delivered an energy density of 92.63 W h kg-1 at a power density of 1287.52 W kg-1, with superb stability and mechanical endurance that outperformed previously reported ZCO-based materials. Additionally, we delineated the underlying mechanism governing the utilization of redox mediators along with morphological nanoengineering, which will facilitate the current development of state-of-the-art energy storage systems.

Recent Advances of ZnCo2 O4 -based Anode Materials for Li-ion Batteries.

ZnCo2 O4 has been attracted wide research attention as a promising anode material for lithium-ion batteries (LIBs) in recent years based on its high theoretical specific capacity, low toxicity as well as stable chemical properties. However, the further large-scale application of pristine ZnCo2 O4 anode have been impeded because of its undesirable Li+ ion conductivity, low electronic conductivity, and finite stability of electrolytes at high potentials. Recently, optimizing the micro/nano structure, modification with carbonaceous materials, incorporation with metal oxides and constructing a binder-free structure on conductive substrate for ZnCo2 O4 -based materials have been verified as promising effective routes for solving the above problems. In this review, the recent advances in underlying reaction mechanisms, synthetic methods and strategies for improving the performance of ZnCo2 O4 anodes are comprehensively summarized. The factors affecting the electrochemical properties of ZnCo2 O4 -based materials are mainly discussed, and paths to promote the specific capacity and cyclic stability are proposed. Finally, several insights into the future developments, challenges, and prospects of ZnCo2 O4 -based anode materials of LIBs are proposed.

Enhanced Hydrogen Evolution Reaction over Co Nanoparticles Embedded N-Doped Carbon Nanotubes Electrocatalyst with Zn as an Accelerant.

The rational design for transition metals-based carbon nano-materials as efficient electrocatalysts still remains a crucial challenge for economical electrochemical hydrogen production. Carbon nanotubes (CNTs) as attractive electrocatalysts are typically activated by non-metal dopant to promote catalytic performance. Metals doping or metal/non-metal co-doping of CNTs, however, are rarely explored. Herein, this work rationally designs bimetal oxide templates of ZnCo2 O4 for heterogeneously doping Zn and N into Co nanoparticles embedded carbon nanotubes (Co@Zn-N-CNTs). During the formation of CNTs, Zn atoms volatilize from ZnCo2 O4 and in situ dope into the carbon skeleton. In particular, owing to the low electronegativity of Zn, the electrons aptly transfer from Zn to carbon atoms, which generate a high electron density for the carbon layers and offermore preponderant catalytic sites for hydrogen reduction. The Co@Zn-N-CNTs catalyst exhibits enhanced hydrogen evolution reaction activity in 0.5m H2 SO4 electrolyte, with a low onset potential of -20mV versus RHE at 1mA cm-2 , an overpotential of 67mV at 10mA cm-2 , a small Tafel slope of 52.1mV dec-1 , and persistent long-term stability. This study provides brand-new insights into the utilization of Zn as electronic regulator and activity promoter toward the design of high-efficiency electrocatalysts.

Self-assembled nanosheets of ZnCo2O4 as efficient sonophotocatalysts for day light dye degradation

Variety of semiconductor nanomaterials are extensively studied as visible light photocatalysts to degrade organic pollutants, effectively using the abundant solar energy often with the additional help of ultrasound. AB2O4 based spinel compounds are a novel class of semiconductor materials with many suitable properties for this purpose, but relatively less explored. Here in, we report the high adsorption and sonophotocatalytic degradation (∼91%) of methylene blue in the presence of sunlight with ultrasound in 3 h using hydrothermally synthesized self-assembled ZnCo2O4 (ZCO) nanosheets. The sonophotocatalytic functionality of the ZCO nanosheets has been examined in detail and compared with the recent relevant reports.

3D Flower-Like Zinc Cobaltite for Electrocatalytic Reduction of Nitrate to Ammonia under Ambient Conditions.

Nitrate (NO3 - ) as a common pollutant of groundwater causes drinking water safety problems and seriously endangers people's health. Electrochemical reduction of nitrate to ammonia under ambient condition is a green and significant route to reduce the concentration of NO3 - and produce ammonia (NH3 ), known as a complement to the Haber-Bosch reaction. Currently, noble-metal electrocatalysts are often used in electrochemical reduction of NO3 - , but high cost and scarcity limited their application. Herein, three-dimensional (3D) flower-like zinc cobaltite (ZnCo2 O4 ) electrocatalyst was developed to convert nitrate into ammonia at room temperature. The NH3 yield rate could reach up to around 2100 μg mg-1 h-1 at a potential of -0.6 V vs. reversible hydrogen electrode (RHE), which was around 2.0 times higher than that of pristine Co3 O4 . In addition, the NH3 faradaic efficiency of ZnCo2 O4 electrocatalyst could reach around 95.4 % at potential of -0.4 V vs. RHE with good structural and morphological stability, which surpassed most reported non-noble metal-based electrocatalysts. Further studies concluded that the improved activity of electrocatalytic NO3 - reduction was ascribed to the existence of abundant active sites and the charge transfer from Co atoms to Zn atoms after Zn doping. Importantly, this work opens a new path for the development of Co-based materials as electrocatalysts for reducing nitrate to ammonia.

Pulse-duration dependence of saturable and reverse saturable absorption in ZnCo2O4 microflowers

We employed open-aperture Z-scan technique to unveil the third-order optical nonlinearity in ZnCo2O4 (ZCO) microflowers. Our results indicate that intersystem crossing (ISC) lifetime can be used as simple tool to demonstrate remarkably contrasting optical nonlinearity in ZCO. Ultrafast transient absorption measurements reveal that ISC from singlet to triplet state takes place in 5 ps. For femtosecond laser pulses, when the pulse duration is shorter than ISC lifetime, saturable absorption (SA) takes place for all intensities. On the contrary, when the pulse duration is longer than ISC for nanosecond excitation, we observe transition from SA to reverse SA (RSA) at higher intensities via excited-state absorption. We envisage that benefiting from SA and RSA, ZCO emerges as potential candidate for mode locking and optical limiting devices.

Spinel ZnCo2O4 Electrode for Capacitive Desalination: Understanding the Enhanced Capacitive Desalination Performance of Spherical ZnCo2O4 Electrode (Adv. Mater. Interfaces 11/2021)

The ball-like spinel ZnCo2O4 (ZCO) electrode is proposed for capacitive desalination in article number 2100125 by Wei Si and Haibo Li. It exhibits prominent sodium-ion adsorption capacity, such as ultra-high specific capacity and remarkable cyclic stability. Most significantly, the desalination mechanism as well as the preferential removal behavior of Na+, K+, and Mg2+ by ZCO electrode is explored.

Engineering High-Spin State Cobalt Cations in Spinel Zinc Cobalt Oxide for Spin Channel Propagation and Active Site Enhancement in Water Oxidation.

Spinel zinc cobalt oxide (ZnCo2 O4 ) is not considered as a superior catalyst for the electrochemical oxygen evolution reaction (OER), which is the bottleneck reaction in water-electrolysis. Herein, taking advantage of density functional theory (DFT) calculations, we find that the existence of low-spin (LS) state cobalt cations hinders the OER activity of spinel zinc cobalt oxide, as the t2g 6 eg 0 configuration gives rise to purely localized electronic structure and exhibits poor binding affinity to the key reaction intermediate. Increasing the spin state of cobalt cations in spinel ZnCo2 O4 is found to propagate a spin channel to promote spin-selected charge transport during OER and generate better active sites for intermediates adsorption. The experiments find increasing the calcination temperature a facile approach to engineer high-spin (HS) state cobalt cations in ZnCo2 O4 , while not working for Co3 O4 . The activity of the best spin-state-engineered ZnCo2 O4 outperforms other typical Co-based oxides.