Electrocatalytic Oxygen Evolution Reaction Research Articles

NiCo-LDH sheets and Ag3PO4 nanoparticles decorated on graphitic carbon nitride for efficient oxygen evolution reaction

Ternary heterostructure engineering enables highly efficient interfacial charge transfer, which can enhance the efficiency of electrocatalysts for the oxygen evolution reaction (OER), and has thus attracted widespread interest in electrocatalysis. NiCo-LDH/CN/AgPO was synthesized via ultrasonication and subjected to morphological analyses using X-ray diffraction, scanning electron microscopy, and (high-resolution) transmission electron microscopy. The synergistic effects in the ternary heterostructured NiCo-LDH/CN/AgPO nanocomposite comprising 2D nickel-cobalt layered double hydroxide (NiCo-LDH) and silver phosphate (Ag3PO4) nanospecies anchored on graphitic carbon nitride (g-C3N4) nanosheets will provide promising features as an electrode for the alkaline oxygen evolution reaction (OER). The NiCo-LDH/CN/AgPO heterostructure demonstrated exceptional electrocatalytic OER performance compared to AgPO/NiCo-LDH, AgPO/CN, and CN, achieving a low overpotential of 289mV for the OER at 10mAcm-2 in 1.0M KOH. This superior catalytic activity is attributed to the relatively large electroactive surface area, rapid charge transfer capability, and intimate interactions between the components. The innovative design and synthesis of the NiCo-LDH/CN/AgPO heterostructure provide significant potential for constructing electrocatalysts with superior efficacy in oxygen evolution reactions.

Facet-dependent electrocatalytic oxygen evolution of porous network structure Ni-Fe-O materials

Constructing unique crystal facets can increase active sites and enhance electronic structure for electrocatalysts towards the oxygen evolution reaction (OER). Here, we successfully achieved the transformation between the (311) and (222) facets of the NiFe2O4 catalysts by adjusting the ratio of Ni and Fe elements, and it was found that the activity in OER is enhanced with the exposure of (311) facet. The optimal catalyst shows a lower overpotential of 238 mV at 100 mA/cm2 current density and a small Tafel slope of 26.4 mV/dec. Furthermore, benefiting from the porous network structure, the unique super hydrophilic surface and the low-coordination Fe3+ atoms characteristic, the catalyst has an efficient mass transfer channel and fast charge transfer in the electrocatalytic OER process. More metal-O clusters were exposed on the (311) facet surface as the active site, which further improved the catalytic activity. This work presents a successful approach to creating highly active spinel catalysts through facet-engineering for electrocatalytic water splitting.

Effect of Transition Metals (Mn, Co, Ni, and Zn) in Size-Controlled Metal Ferrite Nanocrystals on the Electrocatalytic Oxygen Evolution Reaction

Effect of Transition Metals (Mn, Co, Ni, and Zn) in Size-Controlled Metal Ferrite Nanocrystals on the Electrocatalytic Oxygen Evolution Reaction

Oxygen evolution reaction activity of carbon aerogel supported Pd–Ni–Al catalysts synthesized by microwave irradiation method

The oxygen evolution reaction (OER) is a critical step for oxygen production during the electrochemical splitting of water. Effective OER catalysts support the development of clean energy technologies by increasing the energy efficiency of these processes. In this study, carbon aerogel (CA) was first synthesized as a catalyst support material using sol-gel, supercritical drying, and pyrolysis process. Then, mono-metallic (Pd/CA, Al/CA), bi-metallic (Pd–Al/CA, Pd–Ni/CA), and tri-metallic (Pd–Ni–Al/CA) catalysts were synthesized by microwave irradiation method. Inductively coupled plasma-mass spectrometry (ICP-MS), X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy have been made to examine the structural properties of the synthesized catalysts. Electrochemical analysis was carried out through cyclic voltammetry (CV), chronoamperometry, and electrochemical impedance spectroscopy (EIS) in alkaline media (1 M KOH: Methanol) to examine the effect of metal loading of CA support material towards OER performance. All the compositions showed excellent activity toward OER, among all Pd–Ni/CA catalysts showed the highest activity. The OER peak current increased remarkably up to 48 mA cm−2 with methanol addition, which signifies the substantial application of carbon aerogel supported-Pd-Ni-Al catalysts in direct methanol fuel cells (DMFCs). Pd–Ni/CA display high OER performance with maximum diffusion coefficient, Do (6.6 × 10−8 cm2 s−1) and heterogeneous rate constant, ko (4.706 × 10−4 cm s−1), and smaller value of Tafel slope (128 mV dec−1). Electrochemical studies predicted that all the prepared carbon aerogel supported-Pd-Ni-Al catalysts can be used as efficient catalysts for OER and other related electrocatalysis applications.

Toward Realistic Models of the Electrocatalytic Oxygen Evolution Reaction.

The electrocatalytic oxygen evolution reaction (OER) supplies the protons and electrons needed to transform renewable electricity into chemicals and fuels. However, the OER is kinetically sluggish; it operates at significant rates only when the applied potential far exceeds the reversible voltage. The origin of this overpotential is hidden in a complex mechanism involving multiple electron transfers and chemical bond making/breaking steps. Our desire to improve catalytic performance has then made mechanistic studies of the OER an area of major scientific inquiry, though the complexity of the reaction has made understanding difficult. While historically, mechanistic studies have relied solely on experiment and phenomenological models, over the past twenty years ab initio simulation has been playing an increasingly important role in developing our understanding of the electrocatalytic OER and its reaction mechanisms. In this Review we cover advances in our mechanistic understanding of the OER, organized by increasing complexity in the way through which the OER is modeled. We begin with phenomenological models built using experimental data before reviewing early efforts to incorporate ab initio methods into mechanistic studies. We go on to cover how the assumptions in these early ab initio simulations─no electric field, electrolyte, or explicit kinetics─have been relaxed. Through comparison with experimental literature, we explore the veracity of these different assumptions. We summarize by discussing the most critical open challenges in developing models to understand the mechanisms of the OER.

Ir-Doped Core-Shell Hollow Heterogeneous Nanospindles for Electrocatalytic Oxygen Evolution Reaction.

By utilizing Metal-organic framework (MOF) materials as a base, constructing electrocatalysts with heterogeneous structures offers advantages for catalyzing water splitting. In this study, a hollow heterogeneous nanocatalyst, Ir-MIL-88A@NiFe-LDHs, was prepared by growing a layered double hydroxides (LDHs) shell on MIL-88A substrate. The catalyst shows excellent oxygen evolution reaction (OER) performance in a 1.0 M KOH solution, requiring only 217 mV overpotential to achieve a current density of 10 mA cm-2 with a Tafel slope of 62.18 mV dec-1, indicating significant electrocatalytic performance and reaction kinetics characteristics. Furthermore, long-term OER testing also demonstrates the catalyst's outstanding stability. Emphasizing the interfacial interaction between MOF and LDHs, as well as the synergistic effect among Ni, Fe, and Ir elements, the study highlights how these factors collaboratively control the local electronic structure of the hollow Ir-MIL-88A@NiFe-LDHs, resulting in an efficient MOF-derived electrocatalyst.

An efficient and robust noble-metal-free self-standing bifunctional water electrolysis catalyst: Co3S4@Ex.NiFe-LDH for alkaline water electrolysis

Electrolysis of water integrated with the renewable energy as input source can contribute significantly in the production of green hydrogen, a clean and versatile energy carrier. In water electrolyzer, the hydrogen evolution reaction (HER) at the cathode must act synchronously with the oxygen evolution reaction (OER) at the anode to effectively accomplish total water-splitting. The performance of an electrolyzer is often limited by the low performance of anode and it is important to develop an electrocatalyst which can efficiently perform both HER and OER. Ni and Fe based layered-double-hydroxides (LDHs) have gained a lot of interest owing to their outstanding OER electrocatalytic activity, however they are known to have poor HER performance. To enhance the overall water splitting efficiency of the LDHs, we present a simple approach of preparing a heterojunction of LDH with cobalt sulphide. The bifunctional electroactivity of the designed electrocatalyst Co3S4@Ex.NiFe-LDH, worked efficiently in both HER and OER electrocatalysis. Chalcogenides known for HER, not only improves the HER performance of the composites but also found to reduce the charge transfer resistance. Obtained results showed that when it comes to the OER performance, the recommended catalyst shadows the state of art catalyst RuO2. Additionally, the catalyst has outstanding activity and stability, achieving a current density of around −120 mA/cm2 over a six-day period. The electrolyzer composed of both anode and cathode designated as Co3S4@Ex.NiFe-LDH||Co3S4@Ex.NiFe-LDH only needs a low voltage input of 1.49 V to achieve a total water splitting reaction at required current density of 10 mA/cm2, showing efficacy at the low voltage input. Experimental observations showed Co3S4@Ex.NiFe-LDH performs better than Pt/C–RuO2 in alkaline water electrolysis. The electrolyzer can continuously produce hydrogen at 50 mA/cm2 for more than a week period; indicating its potential for long-term application.

Fabrication of Fe-Zr, Co-Zr, and Ni-Zr Catalysts to Boost CNTs Synthesis from Plastic Wastes and the Electrocatalytic Oxygen Evolution Reaction.

The efficient conversion of plastic wastes to high-value carbon materials like carbon nanotubes (CNTs) is one important issue about the rational recycling, reduction, and reuse of solid wastes. Herein, Fe-, Co-, and Ni-Zr catalysts were prepared and used for CNTs synthesis from polyethylene (PE) waste via a two-stage reaction system. At the same time, the effects of the PE/catalyst ratio and reaction temperature on CNTs synthesis have been studied. Compared with Co-Zr and Ni-Zr, Fe-Zr exhibited the best activity in CNTs synthesis from PE, and it achieved the highest CNTs yield of 806.3 mg/g (per gram of Fe-Zr) at 800 °C with a PE/catalyst ratio of 4. Furthermore, the obtained Fe-Zr/CNTs composite exhibited a low overpotential of 267 mV for the electrocatalytic oxygen evolution reaction (OER) at 20 mA/cm2 in 1 M KOH electrolyte solution, which was 21 mV lower than commercial RuO2 (288 mV) and 50 mV lower than Fe-Zr (317 mV). It was deduced that the in situ growth of CNTs reduced the charge transfer resistance and improved the electron transport efficiency of the Fe-Zr/CNTs composite, leading to superior activity in the electrocatalytic OER. This work provided detailed information for the preparation of the metal/CNTs composite from plastic wastes, which contributed positively to alleviate the environment and energy crisis.

Ultrathin high-entropy layered double hydroxide electrocatalysts for enhancing oxygen evolution reaction

At the heart of the oxygen evolution reaction (OER), the properties of electrocatalysts play a crucial role in determining reaction efficiency. This underscores the need to design and develop highly effective OER electrocatalysts. The unique layer structure and electronic properties make layer double hydroxide (LDH) a promising candidate for driving OER electrocatalysis. Furthermore, high-entropy materials (HEMs) exhibit core effects such as high entropy, lattice distortion, sluggish diffusion, and cocktail effect, which can enhance active sites and optimize binding energy with intermediates. Combining the advantages of these two material categories, we propose the synthesis of high-entropy layered double hydroxides (HE-LDHs) through a straightforward MOF-mediated synthesis method to showcase exceptional electrocatalytic OER performance. Detailed mechanistic studies have shown that its outstanding performance stems from its ultrathin structure and the inherent activity of a high-entropy material that promotes charge transfer, mass transport, and the evolution of reaction intermediates.

Three-dimensional pine-tree-like bimetallic sulfide with maximally exposed active sites by secondary structural restructuring for efficient electrocatalytic OER

Developing efficient, low-cost and bifunctional catalysts with predominant durability for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) is an extraordinary challenge in the preparation of green hydrogen energy by electrochemical water splitting. Three-dimensional (3D) transition metal compounds have become a research hotspot as OER electrocatalysts, which can replace noble metal oxides such as RuO2 and IrO2 to reduce application costs. Herein, we synthesized a novel three-dimensional pine-tree-like bimetallic sulfide arrays on nickel foam (FeCoS/NF) using various optimization strategies such as morphology optimization, in situ growth and introduction of heterogeneous structures. The as-synthesized FeCoS/NF electrocatalyst only requires relatively low overpotential of 156 mV to achieve a current density of 20 mA cm−2 for OER, with a Tafel slope of only 37 mV dec−1. It also has a small charge transfer resistance, an electrochemical surface area and good electrochemical stability in alkaline electrolytes. The excellent performance of FeCoS/NF can be attributed to the synergistic effect and amorphous phase of FeCoS as well as the well-defined pine-tree-like array architecture with a large surface area, abundant active sites, and sufficient gas and electrolyte diffusion channels.

Nanocomposite engineering: Tailoring MXene/Cobalt oxide for efficient electrocatalytic hydrogen and oxygen evolution reactions

Electrocatalytic water splitting has become a significant method of hydrogen production to overcome the energy scarcity and increased rate of pollution caused by the extreme consumption of fossil fuels. Pure cobalt oxide is a potential option for electrocatalytic water splitting due to its higher OER activity but lacks stability, conductivity, and active sites which impair its electrocatalytic performance. In this study, Ti3C2Tx/Co3O4 nanocomposite is synthesized to address the previously noted difficulties along with detailed study of both combinations in three different ratios (1:1, 1:2, 2:1). The outcomes demonstrated that the combination of Ti3C2Tx and Co3O4 in the ratio 1:2 outperformed the component materials in terms of electrocatalytic activity with the lowest overpotential of 270 mV at 50 mA cm‐2−2 for the oxygen evolution reaction (OER), having the least Tafel slope (85 mV dec−1) and Ti3C2Tx/Co3O4 in the ratio 2:1 showed overpotential of 235 mA cm−2, with lowest Tafel slope of 97 mV dec−1 which is the lowest among all electrodes for hydrogen evolution reaction (HER). In Ti3C2Tx MXene with increased O functional group providing adsorption site for hydrogen enables HER in a faster rate. While cobalt oxide enables charge transfer to electronegative MXene which in turn result in stability of the electrocatalyst. In the case of OER, Ti3C2Tx/Co3O4 (1:2) shows the better performance as Co centres act as the active sites for OER while MXene has the role of support matrix for the Co3O4 nanoparticles and prevent aggregation. By choosing these two particular composites, Ti3C2Tx/Co3O4 (2:1) as cathode and Ti3C2Tx/Co3O4 (1:2) as anode overall water splitting was done. For total electrolysis, a potential of 1.73 V was required to provide a current density of 10 mA cm−2 with satisfactory stability. Thus, the produced material is a promising contender for producing green hydrogen in the future.

Lanthanum‐Nickel‐Based Mixed‐Oxide‐Coated Nickel Electrodes for the OER Electrocatalysis

ABSTRACTThe anodic oxygen evolution reaction (OER) remains a bottleneck for electrocatalytic water splitting due to its sluggish kinetics and, thus, high overpotentials. This limits water electrolysis as a key technology for the generation of hydrogen as a sustainable alternative to fossil fuels. For alkaline water splitting, perovskite phases (ABO3) with earth‐abundant first‐row transition‐metals have emerged as a promising material class for OER electrocatalysts. Among these, LaNiO3 has been found to exhibit high intrinsic OER activity. To increase catalyst utilization, a high surface area of the catalyst is desirable and can be achieved by impregnation of porous templates. In this work, La–Ni‐based oxides were prepared via impregnation of activated carbon and subsequent heating, combining precursor calcination and template removal into one step. The phase structure of the samples is analyzed via powder X‐ray diffractometry, and the morphology is determined by scanning electron microscopy. The synergistic effect of B‐site mixing iron as well as A‐site mixing strontium into LaNiO3 is studied and found to increase its OER activity, confirming the activity‐enhancing effect of Fe in Ni‐based OER electrocatalysts. To allow for facile technical application of the catalysts, the electrodes are prepared by coating a perovskite ink onto Ni‐metal as industrially relevant substrates, followed by calcination.

Atomic-Layer IrOx Enabling Ligand Effect Boosts Water Oxidation Electrocatalysis.

An in situ formed IrOx (x ≤ 2) layer driven by anodic bias serves as the essential active site of Ir-based materials for oxygen evolution reaction (OER) electrocatalysis. Once being confined to atomic thickness, such an IrOx layer possesses both a favorable ligand effect and maximized active Ir sites with a lower O-coordination number. However, limited by a poor understanding of surface reconstruction dynamics, obtaining atomic layers of IrOx remains experimentally challenging. Herein, we report an idea of material design using intermetallic IrVMn nanoparticles to induce in situ formation of an ultrathin IrOx layer (O-IrVMn/IrOx) to enable the ligand effect for achieving superior OER electrocatalysis. Theoretical calculations predict that a strong electronic interaction originating from an orderly atomic arrangement can effectively hamper the excessive leaching of transition metals, minimizing vacancies for oxygen coordination. Linear X-ray absorption near edge spectra analysis, extended X-ray absorption fine structure fitting outcomes, and X-ray photoelectron spectroscopy collectively confirm that Ir is present in lower oxidation states in O-IrVMn/IrOx due to the presence of unsaturated O-coordination. Consequently, the O-IrVMn/IrOx delivers excellent acidic OER performances with an overpotential of only 279 mV at 10 mA cm-2 and a high mass activity of 2.3 A mg-1 at 1.53 V (vs RHE), exceeding most Ir-based catalysts reported. Moreover, O-IrVMn/IrOx also showed excellent catalytic stability with only 0.05 at. % Ir dissolution under electrochemical oxidation, much lower than that of disordered D-IrVMn/IrOx (0.20 at. %). Density functional theory calculations unravel that the intensified ligand effect optimizes the adsorption energies of multiple intermediates involved in the OER and stabilizes the as-formed catalytic IrOx layer.

Mesoporous graphene-supported nanostructured nickel telluride for efficient electrocatalytic oxygen evolution reaction

The electrocatalytic oxygen evolution reaction (OER) imposes significant constraints on the operational overpotential of electrochemical energy devices, such as water electrolyzers, metal-air batteries, and fuel cells. However, the sluggish kinetics of OER reactions hinder these applications, which has prompted efforts to design more effective electrocatalysts. In this study, we have synthesized NiTe via in-situ growth into mesoporous graphene (MG), with varying nominal weight percentages (5- wt%, 10- wt%, and 15- wt%) of NiTe. The resulting NiTe/MG nanohybrids displayed hexagonally structured NiTe nanoparticles with a predominant (101) surface that promotes the OER kinetics. The wrinkled 3D mesoporous graphene scaffold facilitated the attachment and dispersion of NiTe particles of nanoscale on its surface, preventing their agglomeration. The porous characteristics of the MG significantly increased the high surface area of the NiTe/MG nanohybrids (583–671 m2 g−1), promoting enhanced accessibility of active sites and mass transport beneficial for the OER. Moreover, the altered electronic structure of the NiTe in the MG nanohybrid indicates enhancing O2 desorption during the OER. The optimized composition of the 10 wt% NiTe-loaded MG nanohybrid electrocatalyst demonstrates superior OER activity compared to other nanohybrids. It exhibits a small overpotential of 250 mV at 10 mA cm−2, a low Tafel slope of 63 mV dec−1 and maintained stability in 1 M KOH (pH = 14) as the electrolyte for a prolonged period. This enhanced OER activity is ascribed to the synergistic effect of MG’s high conductivity and the improved intrinsic activity of NiTe within the nanohybrid structure.

Surface reconstruction and entropy engineering of Ni(OH)2 nanosheets for enhanced electrocatalytic performances of oxygen evolution reaction in alkaline seawater

Hydrogen production via electrochemical splitting of seawater is highly desirable but still facing great challenges. Herein, we report the facile preparation of medium-entropy oxyhydroxides on Ni(OH)2 nanosheets via surface reconstruction and entropy engineering strategies, achieving enhanced electrocatalytic activity and stability for oxygen evolution reaction (OER) in alkaline seawater. The electrochemical oxidation is conducted on Ni(OH)2 nanosheets to create abundant reactive oxygen (reactive-O) atoms on the reconstructed surface, thus forming a reactive-O enriched surface on Ni(OH)2 (NiOx/Ni(OH)2). Additionally, cations are incorporated onto the reconstructed surface of NiOx/Ni(OH)2 via an electrodeposition method, forming the medium-entropy oxyhydroxides on Ni(OH)2 nanosheets ((FeCoCrNi)Ox/Ni(OH)2). Benefiting from the composition and structure advantages, the resulting (FeCoCrNi)Ox/Ni(OH)2@NF demonstrates obviously enhanced performances for OER electrocatalysis, with an overpotential of 239 mV at the current density of 10 mA cm−2 and a low Tafel slope of 24.66 mV dec−1 in 1.0 M KOH + 0.5 M NaCl solution. Furthermore, it exhibits exceptional durability for OER electrocatalysis in alkaline seawater, maintaining over 90.7 % of the OER current density after 100 h.

Biogenic Bovine Serum Albumin/Zn3(PO4)2/Cr2O3 hybrid electrocatalyst for improved oxygen evolution reaction

The fabrication of nanostructured protein-inorganic hybrid materials is crucial for the development of advanced multifunctional materials. Protein-inorganic mesoporous composites are gaining attention due to their remarkable properties, including large surface areas and active surface functional groups. We have successfully synthesized mesoporous BSA/Zn3(PO4)2/Cr2O3 catalysts to improve the kinetics of the oxygen evolution reaction (OER) in electrocatalytic water splitting for sustainable energy generation. This approach utilizes BSA in the synthesis process and is environmentally friendly. By adjusting the BSA quantity, we could control the yield of BSA/Zn3(PO4)2/Cr2O3 mesoporous. We employed various techniques, including FE-SEM, XRD, and FTIR, to analyze the morphology and structural characteristics of the biogenic BSA/Zn3(PO4)2/Cr2O3 electrocatalyst. Our comprehensive evaluation of the electrocatalytic OER activity of the BSA/Zn3(PO4)2/Cr2O3 hybrid structure demonstrated its remarkable performance. The biologically synthesized catalyst exhibited exceptional OER efficiency, maintaining a high current density of 10 mA cm−2 at very low overpotentials (only 216 mV) under alkaline conditions. The elongated peptide backbone of BSA significantly facilitated ion and electron transport, contributing to improved OER activity. The synergistic interaction between various amino acids from BSA and the metal ions within Zn3(PO4)2/Cr2O3 can be attributed to this enhancement, highlighting the potential of this hybrid structure in electrocatalytic OER applications.

Effects of Ir‐Incorporation and Nanostructuring in β‐MnO2 for an Enhanced Electrocatalytic Oxygen Evolution Reaction

Effects of Ir‐Incorporation and Nanostructuring in β‐MnO2 for an Enhanced Electrocatalytic Oxygen Evolution Reaction

Lignin-assisted electronic modulation on NiSe/FeOx heterointerface for boosting electrocatalytic oxygen evolution reaction

The development of productive and durable non-precious metal catalysts for the sluggish oxygen evolution reaction (OER) is critical for water splitting. Herein, a novel NiSe-FeOx heterojunction encapsulated in lignin-derived carbon layer (NiSe-FeOx@LC) was synthesized via hydrothermal self-assembly and in-situ pyrolysis. NiSe-FeOx@LC exhibited excellent OER performance with an overpotential of 265 mV at 50 mA·cm−2, a Tafel slope of 83 mV·dec−1, as well as long-term stability. Both experimental and DFT calculation results indicated that the doping of FeOx into NiSe@LC successfully optimized the dual interface structure between NiSe and FeOx, thereby promoted the d-bands orbital hybridization, that facilitated electron transfer. Besides, the carbon coating effectively protected the NiSe-FeOx components from leaching and agglomerating during the reaction. This study provides insight into the significance of lignin-derived carbon-encapsulated metallic catalyst for electrocatalytic OER process.

Mn incorporated RuO2 nanocrystals as an efficient and stable bifunctional electrocatalyst for oxygen evolution reaction and hydrogen evolution reaction in acid and alkaline

The development of efficient and stable bifunctional overall water-splitting is a crucial goal for clean and renewable energy, which is a challenging task. Herein, we report an Mn-incorporated RuO2 (Mn-RuO2) catalyst for highly efficient electrocatalytic oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in acid and alkaline media. Benefiting from a more electrochemical active area with the incorporation of Mn, the Mn-RuO2 required an overpotential of 200 mV to attain a current density of 10 mA/cm2 for OER in acid. DFT result indicates that the doping of Mn into RuO2 can enhance the OER activity. An acidic overall water-splitting electrolyzer with good stability constructed by bifunctional Mn-RuO2 only requires a cell voltage of 1.50 V to afford 10 mA/cm2 and can operate stably for 50 h at 50 mA/cm2, which is better than the state-of-the-art Ru-based catalyst. Additionally, the Mn-RuO2 exhibits excellent HER and OER activity in alkaline media, and it shows superior activity and durability for overall water-splitting, only needing a cell voltage of 1.49 V to attain 10 mA/cm2. The present work provides an efficient approach to designing and constructing efficient Ru-based electrocatalysts for overall water-splitting.

ZIF‐67 Derived Co‐LDH Nanocubes for Oxygen Evolution Reaction

AbstractTo address the substantial energy needs of the quickly evolving modern civilization, efforts are still needed to provide sustainable renewable energy sources. The electrocatalytic Oxygen evolution reaction (OER) is one of the essential technologies used in the various hydrogen production techniques. ZIF‐67 nanocubes (ZIF‐67 NCs) were synthesized in an aqueous solution and used as sacrificial templates. Cobalt nitrate hexahydrate was added under water bath conditions, resulting in the evolution of numerous small layered layers of cobalt hydroxide. This ultimately led to the formation of multilayered, three‐dimensionally crosslinked Co‐LDH with a porous networked cubic morphology. Hydrolysis of Co2+ at different concentrations produces different degrees of weak acidic environments, and the loose LDH on the cubic structure of the best catalyst, Co‐LDH‐1, exposes more active cobalt sites for the OER, which results in a high electrochemically active surface area, with an overpotential of 354 mV and a Tafel slope of 79.06 mV dec−1 at a current density of 10 mA cm−2, and good stability and low activation under alkaline condition also has good stability and low activation energy. It provides us an easy and practical plan for logically creating ZIF‐derived hydroxide materials, leading to the development of affordable and effective electrocatalysts.