Electrochemical Reduction Process Research Articles

Simplification of solvation shell with water clusters in the simulation of electrochemical nitrogen reduction reaction.

Electrochemical methods for nitrogen reduction have received extensive attention due to the mild reaction conditions. In order to gain an insight into the mechanism of the electrochemical nitrogen reduction process, theoretical simulations are necessary. However, current simulation studies contain many imprecise approximations that may hinder the real recognition of the reaction process. Although solvation methods have recently been developed to provide efficient descriptions, their further applications are hindered by controversy over modeling of solvents and the enormous computational effort required. In this work, we simplify the solvation conditions by using water clusters and compare them with an accurate water layer model. The results demonstrate that the simplified water clusters can effectively capture protons, simulate the surface electric environment, and enable the calculation of the activation energy of the reaction. This method offers an affordable approach for simulating the surface potentials and solvents and provides a new reference for the theoretical study of the electrochemical nitrogen reduction reaction.

Exploring the influencing factors of the electrochemical reduction process on the PEC water splitting performance of rutile TiO2

Exploring the influencing factors of the electrochemical reduction process on the PEC water splitting performance of rutile TiO2

Fabrication of FeCu/CC Composite for Efficient Removal of Nitrate for Aqueous Solution Via Electrochemical Reduction Process

AbstractThe electrochemical nitrate reduction (ENR) for the conversion of nitrate to nitrogen gas is a significant strategy to remediate the eutrophication in surface water. However, the exploitations and practical applications of suitable electrocatalysts still face great challenges. In this study, FeCu bimetal microparticles were deposited onto surface of carbon cloth (CC) to fabricate the FeCu/CC electrocatalyst for the removal of nitrate. Among obtained catalysts, the sample with Fe/Cu molar ratio of 1 : 15 (Fe1Cu15/CC) exhibits the excellent electroreduction efficiency for nitrate removal (R(NO3−), >90 %) but an ineffective selectivity of N2 formation (S(N2), ~23 %). After the anchor of reduced graphite oxide (rGO) to surface of Fe1Cu15/CC, at the optimized condition without the assistance of chlorine oxidation, R(NO3−) and S(N2) of rGO/Fe1Cu15/CC catalyst reach 94.2 % and 72.8 %. After 5 day endurance test, the values of R(NO3−) and S(N2) are still 82.9 % and 62.8 %, demonstrating the promising durability of this catalyst electrode. Meanwhile, the potential application of rGO/Fe1Cu15/CC was explored for the treatment of simulated wastewater discharged by urban wastewater treatment plant, the concentration of total nitrogen (TN) decreases from 15–1.17 mg/L, and this value is lower than TN threshold limit in Class IV of Chinese surface water quality standard.

Investigating proton shuttling and electrochemical mechanisms of amines in integrated CO2 capture and utilization

Carbon capture and utilization (CCU) technologies present a promising solution for converting CO2 emissions into valuable products. Here we show how amines, such as monoethanolamine (MEA) and 2-amino-2-methyl-1-propanol (AMP), influence the electrochemical CO2 reduction process in an integrated CCU system. Using in situ spectroscopic techniques, we identify the key roles of carbamate bond strength, proton shuttling, and amine structure in dictating reaction pathways on copper (Cu) and lead (Pb) electrodes. Our findings demonstrate that on Cu electrodes, surface blockage by ammonium species impedes CO₂ reduction, whereas on Pb electrodes, proton shuttling enhances the production of hydrocarbon products. This study provides additional insights into optimizing CCU systems by tailoring the choice of amines and electrode materials, advancing the selective conversion of CO₂ into valuable chemicals.

Stabilizing In/InN intermediates by electron-deficient carbon for improved CO2 electroreduction to CO

Monitoring and stabilizing the reconstructed active material under operational conditions is crucial for the rational design of electrocatalysts. Herein, we developed a novel hinged structure composited by the electron-deficient carbon and InN nanorods (InN@C) for preserving the high-active In/InN interfaces under electrochemical CO2 reduction process. The electron-deficient carbon, caused by the interfacial rectifying effect, prevents active site annihilation and deep self-reduction of In/InN, leading to synergistic improvements in catalytic activity and long-term stability. Mechanistic studies show that an interfacial dipole between the electron-deficient carbon layer and In/InN promotes CO2 activation and strengthens In−N bonds, inhibiting the deep self-reduction of In/InN. As a result, we achieved remarkable long-term stability of 150 hours, with a Faradaic efficiency of 92 % and a current density of ∼ 40 mA cm−2 at − 0.8 V versus the reversible hydrogen electrode. This study offers a practical approach to preserve the high-active intermediates for synergistically improving the catalytic activity and long-term stability of transition metal compound electrocatalysts.

Ciprofloxacin removal as an emerging contaminant using electrochemical advanced reduction process: Mechanism, degradation pathway and reaction kinetic

The introduction of emerging contaminants (ECs), particularly antibiotics to the water resources has grown in recent years. Due to its widespread application and their toxicity, the ECs are one of the major environmental concerns. The present study is to evaluate the electrochemical removal of ciprofloxacin (CIP) as an emerging contaminant through the advanced reduction process (ARP). Moreover, the degradation pathway, mechanism and its kinetics have provided. In this study, the impacts of main operating variables were evaluated including pH, current density, initial pollutant concentration, sodium sulfite (Na2SO3) concentration, and time on the CIP removal through electrochemical process based-ARP. The obtained results revealed the 94.15 % CIP degradation rate under optimal conditions, at the concentration of 20 mg/L and pH 5 during 60 min. The CIP reduction followed the first-order kinetics with the rate of 0.99. In addition, the ARP along with electrochemical systems as a novel process were suggested as suitable and high efficiency technique for the CIP removal.

Altering preferential product selectivity in electrocatalytic CO2 reduction over fluorine-modified CuIn bimetallic materials

Integrating carbon dioxide (CO2)-derived renewable technologies into the petrochemical industry presents a promising avenue for carbon neutrality. The renewable-energy-powered electrochemical CO2 reduction (eCO2R) process, particularly over Cu-based electrocatalysts, is a valuable asset for our decarbonization efforts to avoid climate consequences. Intending to enhance process efficiency, this work is a distinctive case study emphasizing the need to develop electrocatalysts in conjunction with adjusting operating conditions. A representative case is presented using fluorine-modified CuIn bimetallic electrocatalysts with tunable In/Cu ratios, demonstrating how to alter selectivity preferences based on reactor configuration: Our optimized catalyst system led to the highest faradaic efficiency (FE) for C2+ products of 68 % and the highest C1 FE of 80 % using gas diffusion electrodes (GDE)- and H-cell-type based electrolyzer, respectively. Moreover, the controllable In/Cu ratio and the degree of fluoride doping played a pivotal role in governing the physicochemical properties of the bimetallic electrocatalysts and their eCO2R performance. Diverse characterization tools offered systematic insights into the relationships between catalyst structure and properties, reactor configuration, electrolyte, and performance, aiming to enhance the Technology Readiness Level of the eCO2R process.

PH Variation in the Acidic Electrochemical CO2 Reduction Process.

To address the carbonate problem in the alkaline electrochemical CO2 reduction reaction (CO2RR), more attention has been paid to the CO2RR conducted in acidic electrolytes. The pH stability of such an acidic electrolyte is vital to make sure that the conclusion made in the so-called acidic CO2RR is reliable. Herein, based on reported model electrocatalysts for acidic CO2RR, by monitoring the varying of pH and alkali cation (K+) concentration along with the CO2RR performance in initially acidic electrolyte solution (K2SO4 with pH = 3.5), we unveil their remarkable CO2RR performance along with the rapid pH increase up to 9.5 in the cathode chamber and decrease down to 2.4 in the anode chamber due to the diffusion of K+ along with protons through the proton exchange membrane from the anode to the cathode chamber. We further reveal the rapid collapse of their CO2RR performance in a constant acid solution. This means that some previously reported "remarkable acidic CO2RR performances" actually originate from the alkaline rather than acidic electrolyte, and the conclusions made in such work need to be reconsidered. We also summarize the actual relationship between the CO2RR performance and catholyte pH in widely used Bi- and Sn-based catalysts. This work provides deeper insights into the stability of acidity and the pH effect on electrocatalysts for the CO2RR.

Electrochemical Bioremediation of Uranium (VI) Using Geobacter Sulfurreducens on a Boron Doped Diamond Electrode Surface

Developing nuclear science and technology has increased nuclear waste containing uranium. The contamination associated with nuclear activity is a significant concern for human and environmental health. Due to the high toxicity, radioactivity, and extensive half-life of uranium, it is necessary to find means to remediate contaminated environments, bioremediation being an alternative. Microorganisms can reduce, eliminate, contain, or transform hazardous waste such as radionuclides. This work proposes using Geobacter sulfurreducens to reduce uranium (VI) to uranium (IV). The research consists of electrochemical processes for the G. sulfurreducens' immobilization using boron-doped diamond electrodes (BDD) as electron donors. Taking advantage of the microbial metabolic processes and using U (VI) as an electron acceptor, we can reduce the ion to U(IV) - the electrochemical methods involve using a BDD electrode coupled with Geobacter sulfurreducens. First, using the chronoamperometry technique, a potential of -600mV (vs. Ag/AgCl) was applied. In this way, G. sulfurreducens was immobilized on the BDD electrode surface. After the bacteria immobilization process, a 2mM solution of uranyl acetate was added, an applying the reduction potential oof -600mV, the uranyl ion was reduced and removed from the solution. the bacteria electrochemical immobilization was suggested first due to the changes in current with respect time. This process with G. sulfurreducens was demonstrated with scanning electrode microscopy (SEM), where the bacterium was observed modifying the BDD electrode surface. In the same way, the uranium electrochemical reduction process using the immobilized bacteria on the electrode was suggested and corroborated. Moreover, using SEM and energy dispersive X-ray spectroscopy (EDS), the uranium electrochemical remotion using G. sulfurreducens and the presence of this element on the BDD electrode surface were identified. Finally, Raman spectroscopy analysis was used to determine the uranium species present on the electrode surface. The results obtained help in the advancement of the electrochemical bioremediation processes for the treatment of hazardous waste in the environment. Figure 1

Deciphering the Role of p-Type ZnCo2O4 Semiconductor Nanoflakes for Selective Enhancement of Voltammetric Responses Toward Redox Species System: Interfacial Electron-Transfer Kinetics and Adsorption Capacity

In this study, we describe experimental efforts to decipher the role of ZnCo2O4 nanoflakes (ZCO-NFs) for selective enhancement of voltammetric responses of screen-printed electrode (SPE) toward redox species system. The ZCO-NFs sample was characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM) and UV–vis spectroscopy. The electrochemical characterization of bare SPE and modified SPE electrodes was investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and Mott−Schottky analysis. A series of redox systems including paracetamol (PA), dopamine (DA), chloramphenicol (CAP), furazolidone (FZD), p-nitrophenol (p-NP), carbaryl (CBR), ofloxacin (OXF), and erythromycin (ERY) were selected to investigate for (i) reversible redox process, (ii) irreversible electrochemical oxidation process, and (iii) irreversible electrochemical reduction process on both bare-SPE and ZCO-NFs/SPE electrodes. The obtained results showed that ZCO-NFs possess the selective enhancement of electrochemical response for redox systems with an increase of 24%–90% for PAR, DA, FZD, CAP, and CBR and a decrease of 13%–49% for p-NP, ERY, and OFX. The different electrochemical response of redox species at nanostructured semiconductor electrodes is attributed to the contribution of both the adsorption capacity of redox species and the interfacial electron transfer process between electrode and redox species. An insight into the interfacial electron transfer kinetics and its contribution to the enhancement of electrochemical response on p-type semiconductor electrode is helpful in designing high-performance sensing platforms based on spinel oxide nanostructures.

Electrochemical reduction processes and extraction of titanium with different valence states in molten CaO-CaF2 slags

Titanium is an excellent structural and functional material. At present, the production of titanium has long process cycle, high energy consumption, serious pollution and other characteristics, so the development of low-cost titanium production methods has extremely far-reaching significance. In this work, the electrochemical reduction process of Ti(IV) and Ti(II) in the CaF2-CaO melt were investigated by cyclic voltammetry and square wave voltammetry measurements at 1740 K, respectively. In the CaF2-CaO-5 wt% TiO2 melt, Ti(IV) ions were reduced to Ti by one step. One measure was taken to lower the valence state of Ti ions: Ti(IV) ions in the melt was changed to Ti(II) by adding Ti0. Ti(IV) ions were reduced in two steps: in the CaF2-CaO-5 wt% TiO2-Ti0 melt, Ti(IV) → Ti(II) and Ti(II) → Ti, respectively, and in the CaF2-CaO-5 wt% TiO, the Ti(II) ions were reduced in a single step: Ti(II) → Ti. It was found that both migration and mass transfer affected the reduction processes. In contrast to the Ti(IV) reduction to Ti process, the Ti(II) reduction to Ti process showed a higher diffusion rate. Electrolytes and electrodes were analyzed after titanium electrodeposition by XRD. It was found that there were no metal titanium was detected in the electrolyte placed close to the cathode after electrodeposition. It believed that the formed metallic Ti reacted with dissolved O2- in the melt to form TiO. The reduction process of Ti(IV) on the iron electrode was investigated, the metal Ti was reduced by alloying process, the oxidation of Ti was hindered, there was a dense structure layer of CaTiO3 outside the reduced metal Ti that prevented the ions transfer and affected the Ti(IV) ions migration process, which might be the main factor that the Ti(IV) reduction process was controlled by migration. The lower valence state of Ti in the melt promoted the formation of Ca2TiO4, which increased the ion migration rate and decreased the mass transfer rate. It was suggested that titanium or titanium alloys may be prepared by reducing the valence of Ti(IV) in minerals and altering the melt composition. It is feasible to prepare titanium and titanium alloys by MOE short process using ore as raw material.

Synthesis of n‐Propanol from CO2 Electroreduction on Bicontinuous Cu2O/Cu Nanodomains

Abstractn‐propanol is an important pharmaceutical and pesticide intermediate. To produce n‐propanol by electrochemical reduction of CO2 is a promising way, but is largely restricted by the very low selectivity and activity. How to promote the coupling of *C1 and *C2 intermediates to form the *C3 intermediate for n‐propanol formation is challenging. Here, we propose the construction of bicontinuous structure of Cu2O/Cu electrocatalyst, which consists of ultra‐small Cu2O nanodomains, Cu nanodomains and large amounts of grain boundaries between Cu2O and Cu nanodomains. The n‐propanol current density is as high as 101.6 mA cm−2 at the applied potential of −1.1 V vs. reversible hydrogen electrode in flow cell, with the Faradaic efficiency up to 12.1 %. Moreover, the catalyst keeps relatively stable during electrochemical CO2 reduction process. Experimental studies and theoretical calculations reveal that the bicontinuous structure of Cu2O/Cu can facilitate the *CO formation, *CO‐*CO coupling and *CO‐*OCCO coupling for the final generation of n‐propanol.

Synthesis of n-Propanol from CO2 Electroreduction on Bicontinuous Cu2O/Cu Nanodomains.

n-propanol is an important pharmaceutical and pesticide intermediate. To produce n-propanol by electrochemical reduction of CO2 is a promising way, but is largely restricted by the very low selectivity and activity. How to promote the coupling of *C1 and *C2 intermediates to form the *C3 intermediate for n-propanol formation is challenging. Here, we propose the construction of bicontinuous structure of Cu2O/Cu electrocatalyst, which consists of ultra-small Cu2O nanodomains, Cu nanodomains and large amounts of grain boundaries between Cu2O and Cu nanodomains. The n-propanol current density is as high as 101.6 mA cm-2 at the applied potential of -1.1 V vs. reversible hydrogen electrode in flow cell, with the Faradaic efficiency up to 12.1 %. Moreover, the catalyst keeps relatively stable during electrochemical CO2 reduction process. Experimental studies and theoretical calculations reveal that the bicontinuous structure of Cu2O/Cu can facilitate the *CO formation, *CO-*CO coupling and *CO-*OCCO coupling for the final generation of n-propanol.

High Throughput Correlative Electrochemistry-Microscopy Analysis on a Zn-Al Alloy.

Conventional electrodes and electrocatalysts possess complex compositional and structural motifs that impact their overall electrochemical activity. These motifs range from defects and crystal orientation on the electrode surface to layers and composites with other electrode components, such as binders. Therefore, it is vital to identify how these individual motifs alter the electrochemical activity of the electrode. Scanning electrochemical cell microscopy (SECCM) is a powerful tool that has been developed for investigating the electrochemical properties of complex structures. An example of a complex electrode surface is Zn-Al alloys, which are utilized in various sectors ranging from cathodic protection of steel to battery electrodes. Herein, voltammetric SECCM and correlative microstructure analysis are deployed to probe the electrochemical activities of a range of microstructural features, with 651 independent voltammetric measurements made in six distinctive areas on the surface of a Zn-Al alloy. Energy-dispersive X-ray spectroscopy (EDS) mapping reveals that specific phases of the alloy structure, particularly the α-phase Zn-Al, favor the early stages of metal dissolution (i.e., oxidation) and electrochemical reduction processes such as the oxygen reduction reaction (ORR) and redeposition of dissolved metal ions. A correlative analysis performed by comparing high-resolution quantitative elemental composition (i.e., EDS) with the corresponding spatially resolved cyclic voltammograms (i.e., SECCM) shows that the nanospot α-phase of the Zn-Al alloy contains high Al content (30-50%), which may facilitate local Al dissolution as the local pH increases during the ORR in unbuffered aqueous media. Overall, SECCM-based high-throughput electrochemical screening, combined with microstructure analysis, conclusively demonstrates that structure-composition heterogeneity significantly influences the local electrochemical activity on complex electrode surfaces. These insights are invaluable for the rational design of advanced electromaterials.

Efficient preparation of metallic titanium from lower valence titanium chloride slurry by electrochemical reduction in molten salts

Short extraction of metallic titanium by the electrochemical reduction process in molten salt has attracted increasing interest due to its many advantages. The electrolysis of high-purity titanium to produce lower valence titanium chlorides has so far been industrialized as balancing agents but large-scale production is still challenging due to the high cost of raw materials and easy deterioration. Herein, metallic titanium was extracted from lower valence titanium chlorides (LTCs) slurries by electrochemical reduction in molten salts. The results of LTC slurries at 260 ºC for 48 h revealed the formation of red-violet α- and γ- TiCl3 with an Al content below 0.09 wt%, which gradually reduced to form metallic titanium in molten salt electrolytes. Porous metallic Ti powders were obtained from TiCl3 by electrochemical reduction in KCl-LiCl-MgCl2 molten salt at 400 °C. The reaction at the anode area was accompanied by TiCl4 gas overflow, and continuous electrolysis of metallic titanium was achieved by supplementing the consumed TiCl3. Overall, the proposed electrolysis process looks promising for large-scale applications due to its simple electrolysis equipment, relatively stable electrolyte components, and good product quality, thereby worth further future investigation.

Uniaxial Magnetization and Electrocatalytic Performance for Hydrogen Evolution on Electrodeposited Ni Nanowire Array Electrodes with Ultra-High Aspect Ratio.

Ni nanowire array electrodes with an extremely large surface area were made through an electrochemical reduction process utilizing an anodized alumina template with a pore length of 320 µm, pore diameter of 100 nm, and pore aspect ratio of 3200. The electrodeposited Ni nanowire arrays were preferentially oriented in the (111) plane regardless of the deposition potential and exhibited uniaxial magnetic anisotropy with easy magnetization in the axial direction. With respect to the magnetic properties, the squareness and coercivity of the electrodeposited Ni nanowire arrays improved up to 0.8 and 550 Oe, respectively. It was also confirmed that the magnetization reversal was suppressed by increasing the aspect ratio and the hard magnetic performance was improved. The electrocatalytic performance for hydrogen evolution on the electrodeposited Ni nanowire arrays was also investigated and the hydrogen overvoltage was reduced down to ~0.1 V, which was almost 0.2 V lower than that on the electrodeposited Ni films. Additionally, the current density for hydrogen evolution at -1.0 V and -1.5 V vs. Ag/AgCl increased up to approximately -580 A/m2 and -891 A/m2, respectively, due to the extremely large surface area of the electrodeposited Ni nanowire arrays.

Iodonium-based pro-adhesive layers for robust adhesion of PEDOT:PSS to surfaces

ABSTRACT Electrochemical grafting of organic molecules to metal surfaces has been well-known as an efficient tool enabling tailored modification of surface at the nanoscale. Among many compounds with the ability to undergo the process of electrografting, iodonium salts belong to less frequently used, especially when compared with the most popular diazonium salts. Meanwhile, due to their increased stability, iodonium salts may be used in situations where the use of diazonium salts is constrained. The aim of this study was to examine the effect of the electrochemical reduction of iodonium salts on the physicochemical properties of Pt electrodes, and the possibility to form pro-adhesive layers facilitating further functionalization purposes. Consequently, we have selected four commercially available iodonium salts (diphenyliodonium chloride, bis(4-tertbutylphenyl)iodonium hexafluorophosphate, (4-nitrophenyl)(2,4,6-trimethylphenyl)iodonium triflate, bis(4-methylphenyl)iodonium hexafluorophosphate), and attached them to the surface of Pt electrodes by means of an electrochemical reduction process. As-formed layers were then extensively characterized in terms of wettability, roughness and charge transfer properties, and used as pro-adhesive coatings prior to the deposition of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate), PEDOT:PSS. Due to the increase in hydrophilicity and roughness, modified electrodes increased the stability of PEDOT:PSS coating while maintaining its high capacitance.

Understanding first electron transfer kinetic process of electrochemical nitrate reduction to ammonia on Fe2O3 nanorods array

Electroreduction reaction of nitrate (NO3RR) to ammonia (NH3) using reproducible energy is an effective alternative strategy to energy-intensive Haber-Bosch process and potentially energy storage. However, the reaction needs coupling of multiple electrons and protons, considering it a grand challenge to NH3 yield and selectivity affected by slow electron transfer kinetic processes. Herein, we investigate the electrode kinetics process by Tafel plots on Fe2O3 nanorods array electrocatalysts, confirming that the process of the first electron transfer is involved in the rate-determining step (RDS) for NO3RR. The reaction rate constant (k) of the first electron transfer (NO3– + e-→*NO3) indicates that Fe2O3 electrocatalyst treated at 450 ℃ has a faster electron transfer kinetic and thus exhibits a higher NH3 yield. Furthermore, operando EIS and in situ Raman spectroscopic characterizations demonstrate that electron gaining and losing process of Fe promotes the transfer of the first electron to NO3–, thus substantially accelerating the kinetic process of the RDS. These results provide key insight into the metal oxide-based electrocatalysts kinetic processes on the performance of NO3RR.

Identification and quantification of electron-generated atomic hydrogen through in-situ electron spin resonance and density functional theory

Electro-generated atomic hydrogen (H*) plays a crucial role in the electrochemical reduction process, serving as the key species that mediates the electrocatalytic hydrogenation reduction of stubborn contaminants in wastewater treatment. However, precisely identifying and quantifying transient atomic H* presents a significant challenge due to its limited lifespan and its existence solely within the boundary layer at the electrode/solution interface. Herein, we developed the electrodeposition of palladium nanoparticles onto carbon cloth and assessed its effectiveness as a cathode for generating and stabilizing atomic H*. The environmental application of atomic H* was validated through the dechlorination of 2, 4-dichlorophenol wastewater and the reduction of antimonite wastewater. Additionally, the identification of atomic H* was verified by electrochemical measurements, high-resolution mass spectra, and density functional theory. Moreover, introducing an excess of a spin trapping agent (5,5-dimethyl-1-pyrroline-N-oxide) and fast in-situ spin trapping facilitated creating favorable conditions for efficient trapping of atomic H* and subsequent electron spin resonance (ESR) spectroscopy quantification analysis. Subsequently, the quantification of atomic H* was achieved by double integration of the ESR signal of spin adduct and comparison with the external standard agent (4-hydroxy-2,2,6,6-tetramethyl-1-piperidine 1-oxyl). This study introduces a novel method for in-situ spin trapping and quantification of atomic H*, facilitating the advancement of electrochemical reduction technology and its application in wastewater treatment.

Constructing surface concave defects on NiFe layered double hydroxides by electrochemical reduction for efficient oxygen evolution reaction

NiFe-LDH has been proved to be one of the most effective non-noble metals electrocatalysts for oxygen evolution reaction, but inadequate exposure of the active sites prevents its performance from being comparable to noble metal catalysts. Herein, we prepare 3D nanoflower-like NiFe-LDH composed of bumpy, thin nanosheets by hydrothermal combined with electrochemical reduction method. Various characterization results reveal that the nanosheets of NiFe-LDH are partial exfoliated and reduced by the atomic H* and H2 in the electrochemical reduction process, which results in the generation of surface oxygen vacancies (Vos), forming plenty concave defects in the surface of nanosheets. The optimized partially surface reduced NiFe-LDH exhibits an outstanding catalytic activity for OER with long-term stability. The overpotential is only 185 mV at 100 mA cm−2 with no obvious deterioration in 100 h operation process. The enhanced activity is attributed to the more exposure and the adjustment of electron density of metal active sites. This work provides a universality method to strip nanosheets and induce oxygen vacancies on oxygenated catalysts.