Ni Hydroxide Research Articles

Revealing the Surface Reconstruction on the High OER Catalytic Activity of Ni3S2.

Sluggish oxygen evolution reaction (OER) is a crucial part of water splitting and solar fuel generation, which limits their utilization. Ni3S2 is a promising OER catalyst, in which surface reconstruction is an important step to improve performance. In this study, DFT calculations were employed to investigate the effect of surface reconstruction on (001), (110), and (101) surfaces of Ni3S2 in alkaline OER. According to the Pourbaix diagram and surface free energy landscape, Ni3S2 is prone to transform into Ni oxides and (oxy) hydroxides under alkaline OER conditions. This process induces exposed S atoms to leach and O from the electrolyte to incorporate S sites, thereby lowering the Bader charge of *O and increasing [[EQUATION]], and then decrease [[EQUATION]], the free energy penalty of the potential determining step. In general, the surface reconstruction enhances the OER activity through S leaching and adjusting the coordination environment. We believe this work not only provides insights into the clarification of surface reconstruction, but also provides a valuable guideline for the further discovery of efficient TM-based sulfides.

Operando Nanoscale Characterization Reveals Fe Doping of Ni Oxide Enhances Oxygen Evolution Reaction via Fragmentation and Formation of Dual Active Sites.

Efficient catalytic water splitting demands advanced catalysts to improve the slow kinetics of the oxygen evolution reaction (OER). Earth-abundant transition metal oxides show promising OER activity in alkaline media. However, most experimental information available is either from post-mortem studies or in-situ space-averaged X-ray techniques in the micrometer range. Therefore, the composition of the active centers under operando conditions is still under debate. In this work, we combine nanoscopic and spectroscopic measurements on the hydroxylation of molecular beam epitaxy (MBE)-prepared Ni and NiFe oxides nanoislands with operando local investigations of Ni and NiFe hydroxide electrocatalysts under OER conditions to reveal the nature of the active centers in 2D OER catalysts. Our results reveal that Fe doping increases the active surface area by island fragmentation, and boosts the intrinsic activity by creating optimized active centers consisting of both Ni and Fe atoms. In addition, our findings show that operando characterization at the nanoscale is crucial to reveal the dynamic nature of the interface of 2D catalysts under reaction conditions.

Unveiling the performance of ultrathin bimetallic CoxNi1−x(OH)2 nanosheets for pseudocapacitors and oxygen evolution reaction

Bimetallic Co–Ni hydroxide nanosheets for pseudocapacitors and oxygen evolution reaction.

Electrochemical Performance of LiNi0.5Mn0.5O2 Electrode in All-Solid-State Battery

IntroductionOxide-based all-solid-state batteries (Ox-ASSBs) have been attracting attention as next-generation secondary batteries because of their high safety and high energy density. Recently, Ox-ASSBs have been reported by use of LISICON-type Li3.5Ge0.5V0.5O4(LGVO) as a solid electrolyte and layered NaCl-type LiCoO2 and LiNi1/3Mn1/3Co1/3O2 as positive electrodes. We have focused on Li2MnO3-based positive electrodes without Co, as shown in Li4/3-2/3x Mn2/3-1/3x NixO2 (0<x<1/2). LiNi0.5Mn0.5O2(x=1/2, LNMO) combines high capacity and thermal stability. It is well known that disordering of Li and Ni in the layered NaCl-type structure occurs during sintering and that oxide ions involve in charge compensation at higher voltages. Accordingly, the electrochemical properties vary depending on the amount of Ni substitution and excess Li relative to the transition metal in conventional Li-ion battery. Therefore, we have investigated an Ox-ASSB battery using LNMOs as a positive electrode, specifically focusing on effects of both Li, Ni-disordering and their sintering temperatures on the performance while controlling chemical compositions precisely.ExperimentalLNMO were prepared by co-precipitation method. The precursor Ni and Mn hydroxides ware prepared from Ni(NO3)2･6H2O and Mn(NO3)2･6H2O. The precursor and LiOH･H2O were mixed to a specified chemical composition ratio, formed under pressure, and calcined at 1073, 1173, 1273 K to obtain LNMO. The solid electrolyte LGVO was synthesized by sintering a mixture of Li4GeO4 and Li3VO4 at 973 K. The LNMO composite cathode layer on LGVO was prepared by applying a composite LNMO cathode slurry, drying, and sintering at 1023K for 6 hours The solid electrolyte LGVO and cathode material LNMO contain 5 % Li3BO3 as a sintering aid. The crystalline phase was identified by powder X-ray diffraction measurement by CuKα radiation. The chemical bonding state was analyzed by X-ray photoelectron spectroscopy Electrochemical testing was performed by LNMO/ LGVO / sulfide solid electrolyte Li10GeP2S12 / In-Li cell (Φ10mm) at 323 K. The rate of constant current was 1/100 C in the 2.0-(3.6~4.0) V.Results and discussionThe samples sintered at 1073, 1173, and 1273 K showed a single phase of LiNi0.5Mn0.5O2. The I (003)/I (104) intensity ratio of Bragg peak, which is an index of the degree of disordering of Li and Ni, increased with increasing sintering temperature. The disordering of Li and Ni in the layered NaCl-type structure occurred with increasing sintering temperature. Fig. 1 shows the charge-discharge measurement results of Ox-ASSB using LNMO (x=1/2) sintered at 1173 K. Followed by a single phasic reaction, a plateau is observed around 3.9 V, the discharge capacities are 175 mAhg-1 at the end-of-charge voltage of 3.6 V and more than 250 mAhg-1 at 4.0 V. Compared to conventional LiB using a liquid electrolyte, this LNMO shows a higher specific capacity, suggesting a possibility to have stable charge-discharge behaviors with LGVO solid electrolyte. These results will be discussed based on the analysis of the cell resistance and the chemical bonding states by XPS measurements before and after charging and discharging. We will present results of other Li-rich positive electrodes in Ox-ASSBs while focusing on a role of oxide ions during and charging-discharging. Figure 1

Active Sites of 3d Transition Metal Oxyhydroxides for OER

3d transitional metal oxyhydroxides, such as Ni and Co oxyhydroxides with Fe doping, are among the most active and most studied OER catalysts in alkaline electrolytes. They are also the catalysts of choice for industrial alkaline water electrolysis. Despite decades of research, the atomic-scale structures of these materials, particularly key Ni (oxy)hydroxide hosts, remain elusive. This presentation aims to fill this critical knowledge gap by combining rigorous Density Functional Theory calculations with in situ Wide Angle X-ray Scattering techniques under quasi-steady state electrochemical cycling conditions. This unique combination has enabled us to unveil the in-situ structures and (ir)reversible transformations of pure undoped Ni (oxy)hydroxides. Such an advance consequently allows us to transcend the limitations of previous modeling based on approximated structures. Specifically, based on the newly identified actual in-situ structures, we discover the existence of a previously unknown synergy at the reaction centers, coupled with the polaron effects, in promoting the oxygen evolution reaction. Such a finding sheds light on the catalytic active sites and oxygen evolution reaction pathways, particularly the exceptional activity of multiple Fe reaction centers on Ni oxyhydroxides. In addition, we found that such a phenomenon is general and also exists on NiM and CoM layered double hydroxides,1, 2 A2B2O7 pyrochlores,3 layered Co oxyhydroxides intercalated with phenanthroline through non-covalent ligand-oxide interaction.4

Recent achievements in nickel based electrochemical biorefinery of 5-hydroxymethylfurfural

The electrochemical conversion of biomass offers a sustainable approach for energy recycling and environmental protection. Specifically, the electro-oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid is notable for its potential to produce value-added products, including biodegradable plastics and other environmentally friendly materials. A critical factor in this process is the performance of the catalysts. Nickel-based catalysts have shown high efficiency and durability, primarily due to the formation of NiOOH active sites. This paper reviews recent advancements in the nickel-based electrocatalytic oxidation of HMF, including the use of Ni, Ni alloys, Ni oxides, Ni hydroxides, and other Ni complex, and discusses the underlying strategies and catalytic mechanisms. Additionally, it introduces the coupling reactions, various reactor designs and outlines future research directions, focusing on exploring reaction mechanisms, developing electrocatalysts, and practical applications of this technology.

Nickel coated paper electrode constructed by interfacial electrodeposition for biomass upgrading at industrial current density

Substituting the kinetically slow oxygen evolution reaction (OER) with biomass electrooxidation significantly decreases the energy demand of water electrolysis. However, exploring and optimizing efficient electrocatalysts remains a challenge for large−scale production of valuable chemicals and hydrogen. Herein, we have constructed a nickel coated paper electrode (NiCo@Ni/CP) composed of crystalline Ni metal and amorphous NiCo hydroxide nanosheets layers via interfacial electrodeposition on carbon paper (CP) for monosaccharide oxidation reactions (MOR), which achieved a formate yield of 82.4 %. Remarkably, the flow electrolyzer maintained an industrial−grade current density of 1 A cm−2 at 1.70 V with exceptional stability over 100 h, also displaying significant co−generation Faradaic efficiencies of approximately 80.0 % and 97.3 % for formate and hydrogen production, respectively. The superior performance is attributed to the redistribution of electrons at the Ni and amorphous NiCo hydroxide interface, which enhances charge transfer and reactant adsorption by adjusting the d−band center, hence reducing deprotonation and C−C bond cleavage energies of xylose during MOR. This work provides a promising strategy for the design of efficient catalysts for biomass upgrading and the production of hydrogen at high current densities.

Sequential oxygen evolution and decoupled water splitting via electrochemical redox reaction of nickel hydroxides

Alkaline water electrolysis is a promising low-cost strategy for clean and sustainable hydrogen production but is largely limited by the sluggish anodic oxygen evolution reaction and the challenges in maintaining adequate separation between H2 and O2. Here, we reveal an anodic-cathodic sequential oxygen evolution process via electrochemical oxidation and subsequent reduction of Ni hydroxides, enabling much lower overpotentials than conventional anodic oxygen evolution. By using (isotope-labeled) differential electrochemical mass spectrometry and in situ Raman spectroscopy combined with density functional theory calculations, we evidence that the sequential oxygen evolution originates from the electrochemical oxidation of Ni hydroxides to NiOO– active species while undergoing a different, reductive step of NiOO– for the final release of O2 due to weakened Ni–O covalency. Based on this sequential process, we propose and demonstrate a hybrid water electrolysis and energy storage device, which enables time-decoupled hydrogen and oxygen evolution and electrochemical energy storage in the Ni hydroxides.

Synthesis of Amorphous Nickel-Cobalt Hydroxides for Ni-Zn Batteries.

In this work we developed a hydrothermal method for synthesizing amorphous Ni-Co hydroxide (NC(OH)) and in the subsequent step crystalline NiCo2O4 (NCO) has been produced using water as the solvent. For nickel-zinc batteries, NC(OH) was found to have superior performance to its NCO prepared by two-step process. The thermal stability analysis exhibited the optimum temperature to obtain the NC(OH), and NCO electrode materials. The XRD pattern showed mixed phases containing both Ni and Co hydroxides (during the initial step) and in the subsequent step (calcined) the formation of cubic spinel structure was noticed. For NC(OH), aggregated particles with irregular morphology were observed while clustered nanorod-like shapes were noticed for NCO samples. To be noted, that the nanorod morphology was obtained through a facile approach without employing any structure-directing agent. Both NC(OH) and NCO were employed as cathodes for Ni-Zn battery studies against Zn foil anode with a polyamide-based separator soaked in 6 M KOH saturated with ZnO additive was used as electrolyte. The Ni-Zn cell was fabricated in CR2032 coin cell configuration. The electrochemical studies such as cyclic voltammetry (CV) showed the characteristic redox peaks for NC(OH) sample exhibiting high peak current compared to its NCO counterpart. The NC(OH) had a capacity of 268 mAh g-1 against 120 mAh g-1 for NCO at a current density of 1 Ag-1. The cell was able to retain 85 % of the capacity at the end of 500 cycles and showed remarkable rate capability. The Ni-Zn battery presents energy and power densities of 428.8 Wh Kg-1 and 2.68 kW Kg-1, respectively surpassing the normal values reported for aqueous rechargeable batteries. Owing to the presence of Ni and Co in hydroxide form (reduced crystallinity) the NC(OH) sample showed improved electrochemical activity. This work provides a facile approach and effective strategy for developing bimetallic hydroxides for optimal energy storage performance.

Revealing Enhanced Active Oxygen Formation by Incorporating Chromium into Nickel Hydroxide Nanosheets for Improved Oxygen Evolution Reaction.

Nickel-based oxyhydroxides have emerged as promising catalysts for the oxygen evolution reaction (OER) among Earth-abundant metals. While the incorporation of foreign elements is recognized to enhance catalytic activity, the origin of this enhancement is still debated. We synthesize and examine Ni hydroxide nanosheets, both with and without Cr doping, to elucidate the underlying enhancements. Operando UV-vis and Raman spectroscopy are employed to unravel the behavior of the catalysts. The Cr doping facilitates the oxidation of Ni, resulting in the generation of active oxygen species. The enriched active oxygen species improves OER performance through a lattice oxygen-mediated pathway in Fe-free KOH, and further contribute to the creation and increased activity of FeOxHy sites in the presence of Fe impurities. This work provides a mechanistic understanding of the performance enhancement in Ni-based catalysts through Cr doping and suggests a strategy for the design of more efficient catalysts in the future.

Nickel-based hydroxide composite as electrocatalyst for hydrogen evolution reaction

The development of earth-abundant transition-metal-based electrocatalysts for hydrogen evolution reaction (HER) is commercial. In this work, Fe (Co) and Ni hydroxide nanocomposites on Ni foam were synthesized as HER catalyst, FeNi-LDH/NF has the overpotentials of 291 mV at 50 mA cm−2 and 369 mV at 100 mA cm−2. It is found that FeNi-LDH/NF and CoNi-LDH/NF have large Cdl and ECSA, low Rct. Therefore, this simple method to prepare FeNi-LDH/NF and CoNi-LDH/NF can enhance the properties of electrocatalysts, which make FeNi-LDH/NF and CoNi-LDH/NF a promising material to replace noble metal-based catalysts.

Impact of Organic Anions on Metal Hydroxide Oxygen Evolution Catalysts.

Structural metamorphosis of metal-organic frameworks (MOFs) eliciting highly active metal-hydroxide catalysts has come to the fore lately, with much promise. However, the role of organic ligands leaching into electrolytes during alkaline hydrolysis remains unclear. Here, we elucidate the influence of organic carboxylate anions on a family of Ni or NiFe-based hydroxide type catalysts during the oxygen evolution reaction. After excluding interfering variables, i.e., electrolyte purity, Ohmic loss, and electrolyte pH, the experimental results indicate that adding organic anions to the electrolyte profoundly impacts the redox potential of the Ni species versus with only a negligible effect on the oxygen evolution activities. In-depth studies demonstrate plausible reasons behind those observations and allude to far-reaching implications in controlling electrocatalysis in MOFs, mainly where compositional modularity entails fine-tuning organic anions.

Optimisation of Mo doping to form NiCoMo ternary sulphides for high performance charge storage.

Multi-component synergy and the rational design of structures are effective methods for preparing electrode materials for high-performance energy storage devices. Transition metal-based hydroxides offer advantages such as a large specific surface area, large interlayer spacing, multiple redox states, and high theoretical capacity, making them commonly used as positive materials for supercapacitors. However, challenges like low conductivity and severe agglomeration limit their practical application. This study focuses on the preparation of Ni, Co, and Mo ternary transition metal hydroxides by incorporating the Mo element to optimize their structure. Furthermore, sulfide ions were utilized in an ion exchange process to replace hydroxides, resulting in the formation of NiCoMo ternary sulfide electrode materials. By adjusting the amount of Mo added, a spherical nanoneedle-shaped N2C1MS0.2-2 electrode material was successfully synthesized. This electrode exhibited a specific capacity of 2094 F g-1 at a current density of 1 A g-1. In addition, an asymmetric supercapacitor was assembled with activated carbon as the negative electrode and N2C1MS0.2-2 as the positive electrode, which had an energy density of 46.2 W h kg-1 at a power density of 800 W kg-1, a capacity retention of 89.7% and a coulombic efficiency of 97.8% after 10 000 cycles. This study provides a reference for the design and preparation of ternary sulphide electrode materials.

Exploring Fe Retention in Oxygen Evolution Reaction Catalysts Via Composition Engineering

The oxygen evolution reaction (OER) is an electrochemical half-reaction critical to electrolyzer and metal-air battery technologies. It is well established that Ni (oxy)hydroxides are state-of-the-art electrocatalysts for the OER in basic media when Fe impurities are present in these systems. Morphological studies have shown that these catalysts are prone to dramatic nanoscale reconstruction under electrochemical conditions, implying dissolution, migration and redeposition processes of the catalyst’s components. Processes involving the displacement of Fe are especially important to understand, as these impurities, while essential for high activity at the anode, are often associated with cathode fouling. Describing the parameters that govern Fe leaching is thus of interest for the design of materials aimed toward the maintenance of device performance and longevity. To study how the degree of restructuring relates to Fe dissolution and redeposition, we have prepared a series of electrolyte accessible Ni(z)Co(1-z)O(x)H(y) (z = 0, 0.2, 0.4, ...) thin film catalysts, whereby increased amounts of Co limit the material’s dynamic behavior. By introducing tertiary cations with trackable redox features, we map a parameter space of catalyst composition more or less capable of retaining surface active phases. Parallels with Ni-Co + Fe catalysts are then carried out in Fe-free electrolyte to disrupt absorption-desorption equilibria and connect host-structure dynamics to equilibrium concentrations of electrolyte impurities.

(Invited) OER Active Phases, Catalytic Mechanism and Reaction Centers of Ni (oxy)Hydroxide with and without Fe Impurities

Identifying atomic-scale structures of catalytically active phases, catalytic mechanism and reaction centers are crucial for establishing rigorous structure-activity relationship of highly active catalysts and for designing new catalysts with further improved performance. Due to the lack of theoretical guidance and challenges in experimental structural characterization during OER conditions, in-situ structures and stabilities of two (a-Ni(OH)2 and g-NiOOH with water and ion intercalation) out of four (oxy)hydroxide phases (another two are b-Ni(OH)2 and b-NiOOH without water and ion intercalations) remain elusive after at least half a century study, which has hindered the establishment of rigorous structure-activity relationship of Ni (oxy)hydroxides and their derivatives for the OER. As a consequence, it is still unclear regarding which phases should be the hosts and the precursors of choice for highly active catalysts. Here, by combining ab initio molecular dynamics simulation, in-situ wide-angle X-ray scattering, and electrochemical measurements, we provide direct atomic-scale and self-consistent insights into the crystal structure, water and ion intercalation, and stable potential windows of complex a-Ni(OH)2 and g-NiOOH with respect to b-phases. DFT calculations indicate that b-NiOOH and g-NiOOH with Fe impurities have similar OER activity to or even higher OER activity than that of g-NiFe LDH, with a dependence on the Fe coverage on the edges. Current work suggests that both b-NiOOH and g-NiOOH are potential hosts of highly active OER catalysts, which enlarges the phase space for the design of OER catalysts with further improved performance.We will discuss the implications of the above insights toward understanding of the active phases, reaction centers and catalytic mechanism of NiM and CoM layered double hydroxides. If time permits, we will further review our work our work regarding the promotion effects of non-covalent ligand-oxide interaction in OER and mitigation of RuO6 octahedron distortion by enhanced A-site electronegativity in pyrochlore for acidic water oxidation.

Probing Electrocatalytic Synergy in Graphene/MoS2/Nickel Networks for Water Splitting through a Combined Experimental and Theoretical Lens.

The development of low-cost and active electrocatalysts signifies an important effort toward accelerating economical water electrolysis and overcoming the sluggish hydrogen or oxygen evolution reaction (HER or OER) kinetics. Herein, we report a scalable and rapid synthesis of inexpensive Ni and MoS2 electrocatalysts on N-doped graphene/carbon cloth substrate to address these challenges. Mesoporous N-doped graphene is synthesized by using electrochemical polymerization of polyaniline (PANI), followed by a rapid one-step photothermal pyrolysis process. The N-doped graphene/carbon cloth substrate improves the interconnection between the electrocatalyst and substrate. Consequently, Ni species deposited on an N-doped graphene OER electrocatalyst shows a low Tafel slope value of 35 mV/decade at an overpotential of 130 mV at 10 mA/cm2 current density in 1 M KOH electrolytes. In addition, Ni-doped MoS2 on N-doped graphene HER electrocatalyst shows Tafel slopes of 37 and 42 mV/decade and overpotentials of 159 and 175 mV, respectively, in acidic and alkaline electrolytes at 10 mA/cm2 current density. Both these values are lower than recently reported nonplatinum-group-metal-based OER and HER electrocatalysts. These excellent electrochemical performances are due to the high electrochemical surface area, a porous structure that improves the charge transfer between electrode and electrolytes, and the synergistic effect between the substrate and electrocatalyst. Raman spectroscopy, X-ray photoelectron spectroscopy, and density functional theory (DFT) calculations demonstrate that the Ni hydroxide species and Ni-doped MoS2 edge sites serve as active sites for OER and HER, respectively. Finally, we also evaluate the performance of the HER electrocatalyst in commercial alkaline electrolyzers.

Redox Promoted Rapid and Deep Reconstruction of Defect-Rich Nickel Precatalysts for Efficient Water Oxidation.

Understanding the reconstruction mechanism to rationally design cost-effective electrocatalysts for oxygen evolution reaction (OER) is still challenging. Herein, a defect-rich NiMoO4 precatalyst is used to explore its OER activity and reconstruction mechanism. In situ generated oxygen vacancies, distorted lattices, and edge dislocations expedite the deep reconstruction of NiMoO4 to form polycrystalline Ni (oxy)hydroxides for alkaline oxygen evolution. It only needs ≈230 and ≈285mV to reach 10 and 100mA cm-2, respectively. The reconstruction boosted by the redox of Ni is confirmed experimentally by sectionalized cyclic voltammetry activations at different specified potential ranges combined with ex situ characterization techniques. Subsequently, the reconstruction route is presented based on the acid-base electronic theory. Accordingly, the dominant contribution of the adsorbate evolution mechanism to reconstruction during oxygen evolution is revealed. This work develops a novel route to synthesize defect-rich materials and provides new tactics to investigate the reconstruction.

Compound database for gaseous metal hydroxides and oxyhydroxides

In this study computational methods are used to derive thermochemical data for Sc, Fe, Co, Ni, and Hf hydroxides and oxyhydroxides. As done previously, molecular geometries and vibrational modes were derived with DFT methods; for the enthalpies of formation more computationally intensive coupled cluster methods were necessary. For each species ΔfHo(298), So(298), and Cp in the form A + BT + CT2 + D/T + E/T2 with A, B, C, D, and E fitted constants are presented. These are combined with previously reported calculations for Al, Cr, Si, Ta, Al, Zr, Y, Yb, Gd, and Mn to build a compound database for metal hydroxides and oxyhydroxides. Sample calculations for applications where high temperature water vapor is encountered are shown. The majority of the database was generated from ab initio calculations; however, experiments were critical benchmarks for many of the species.

Enhanced electrochemical oxidation of 5-hydroxymethylfurfural over tailored nickel nanoparticle assembly

Nickel-based materials are promising electrocatalysts for anodic oxidation of 5-hydroxymethylfurfural (HMF) to value-added 2, 5-furandicarboxylic acid (FDCA). However, their catalytic efficiency is impeded by the sluggish phase transformation of Ni(II) hydroxide to the active Ni(III) oxyhydroxide. Herein, we demonstrate for the first time that the phase transformation kinetics and the HMF oxidation activity of nickel nanoparticles can be modulated by creating self-assemblies with different particle aggregation structures: ordered nanoarrays, disordered nanoarrays, and random aggregates. Notably, the nanoparticle assembly featuring an ordered nanoarray structure exhibits the highest activity, achieving 99.8 % HMF conversion and 99.2 % FDCA yield at 1.36 V. In situ Raman spectroscopy and electrochemical analysis reveal that the ordered nanoarray effectively accelerates the transformation kinetics, attributed to the reduced dehydrogenation barrier of Ni(II) hydroxide as confirmed by density functional theory calculations. This work contributes new insights into the structure-performance relationship of Ni-based catalysts, offering valuable guidance for designing high-performing electrocatalysts.

Voltage activation induced MoO42− dissolution to enhance performance of iron doped nickel molybdate for oxygen evolution reaction

Transition metal-based precatalysts are typically voltage-activated before electrochemical testing in the condition of alkaline oxygen evolution reaction. Nevertheless, the impact of voltage on the catalyst and the anion dissolution is frequently disregarded. In this study, Fe-doped NiMoO4 (Fe-NiMoO4) was synthesized as a precursor through a straightforward hydrothermal method, and MoFe-modified Ni (oxygen) hydroxide (MoFe-NiOxHy) was obtained via cyclic voltammetry (CV) activation. The effects of voltage on Fe-NiMoO4 and the dissolved inactive MoO42− ions in the process were examined in relation to OER performance. It has demonstrated that the crystallinity of the catalyst is reduced by voltage, thereby enhancing its electrocatalytic activity. The electron distribution state can be adjusted during the application of voltage, leading to the generation of additional active sites and an acceleration in the reaction rate. Additionally, MoO42− exhibits potential dependence during its dissolution. In the OER process, the dissolution of MoO42− enhances the reconstruction degree of Fe-NiMoO4 into the active substance and expedites the formation of active Ni(Fe)OOH. Hence, the optimized MoFe-NiOxHy exhibited exceptional electrocatalytic performance, with a current density of 100 mA cm−2 achieved at an overpotential of only 256 mV. This discovery contributes to a more comprehensive understanding of alkaline OER performance under the influence of applied voltage and the presence of inactive oxygen ions, offering a promising avenue for the development of efficient electrocatalysts.