Materials For Oxygen Evolution Reaction Research Articles

Electric field driven de-lithiation: A strategy towards comprehensive and efficient recycling of electrode materials from spent lithium ion batteries

Along with the rapidly growing market of lithium-ion batteries, exploration of efficient strategies to recycle the retired lithium-ion batteries has become an imminent issue. Herein, a green and comprehensive recycling method based on the direct current (DC) electric field driven de-lithiation is developed and the feasibility of the strategy is systematically investigated. The results demonstrate that during the recycling process, the lithium ions can be effectively recovered with simultaneous H2 production. Meanwhile, the de-lithiated electrode materials exhibit a remarkable electrocatalytic activity, which is proved to be related to their high specific surface area as well as their large amount of lattice oxygen. Based on the Daedalian combination of efficient lithium recycling and applications of the de-lithiated cathode materials for oxygen evolution reaction, this study provides an effective strategy for recycling and making maximum use of the spent lithium-ion battery electrode materials based on the DC electric field driven de-lithiation process.

Free-standing bimetallic CoNiTe2 nanosheets as efficient catalysts with high stability at large current density for oxygen evolution reaction

Abstract The oxygen evolution reaction (OER) step for water splitting requires highly efficient, low-cost and stable catalysts. As efficient catalytic materials for OER, bimetallic telluride (CoNiTe2/NF) nanosheets are prepared by the combination of hydrothermal and calcination method in this work. The physicochemical characterizations confirm that the surface of CoNiTe2/NF is covered by bimetallic telluride compounds (CoNiTe2) with 3D morphology composed of thin and defective nanosheets that are well-distributed on nickel foam (NF). Notably, it shows very low overpotential at 10 (181 mV), 500 (230 mV) and 1000 (270 mV) mA cm−2 and low Tafel slope (44 mV dec−1). Besides, it also exhibits excellent durability lasting 24 h at 100, 500 and 1000 mA cm−2, respectively, without distinct deactivation. This outstanding performance could be due to the bimetallic telluride and the strong covalency around the CoNi center caused by Te that plays a crucial role for enhancing the activity of catalyst. The unique morphology could provide large electrochemical active area and exposure higher amounts of active sites. Meanwhile, the self-supported structure, without binders, could also enhance the performance for OER. This work thus provides a promising strategy to synthesize multi-metal telluride materials as highly efficient and stable catalyst for OER at large current density.

Electrochemical synergies of Fe–Ni bimetallic MOF CNTs catalyst for OER in water splitting

This work describes electrocatalytic behavior of amiable and economical iron nickel 2-amioterephthalic acid metal organic framework (FeNiNH2BDC MOF) and its 2–6 wt % carbon nanotubes (CNTs) composites for oxygen evolution reaction (OER) in an alkaline media. Systematic structural and morphological analysis of solvothermally fabricated Iron (Fe) and Nickel (Ni) based MOF and their CNTs composites was carried out by Fourier Transform Infrared Spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray powder diffractometry (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, Brunauer–Emmett–Teller (BET) and energy dispersive X-ray spectroscopy (EDX) techniques. Synergetic effect of bimetallic metal organic framework (MOF) and conductive CNTs support improves the catalytic response of MOF. FeNiNH2BDC-5 wt % CNTs composite demonstrated current density of 10 mA/cm2 at an over potential (η) 0.22 V and onset potential of 1.36 V vs RHE, comparable with RuO2 state-of-the-art catalytic material for oxygen evolution reaction in a fuel cell. Furthermore, FeNiNH2BDC-5 wt % CNTs composite tafel slope of 68.50mV/dec and 0.67s−1 turnover frequency (TOF) ascertain it as a promising alternative candidate towards costly Pt, Pd, Ir and Ru based catalysts.

Bimetallic metal–organic framework-derived carbon nanocubes as efficient electrocatalysts for oxygen evolution reaction

The design and synthesis of efficient electrocatalysts are important for electrochemical conversion technologies. The oxygen evolution reaction (OER) is a key process in such conversions, having applications in water splitting and metal–air batteries. Here, bimetallic carbon nanocubes electrocatalysts are derived from Hofmann-type metal–organic frameworks by carbonization and oxidization (FeNi@OCNC). FeNi@OCNC achieved a current density of 10 ​mA ​cm−2 at a low overpotential of 300.4 ​mV with a very small Tafel slope of 55.4 ​mV dec−1 in 1 ​M KOH, and its activity shows 12 ​h stability. We propose that the coupling effect between Fe, Ni metals is crucial for tuning the electrocatalytic activity, which makes FeNi@OCNC have more oxygen vacancies and higher carbon graphitization degree, thus showing excellent activity. The result may illustrate that bimetallic metal–organic framework-derived carbon nanocubes can be prospective materials for oxygen evolution reaction.

In-situ doping of Co in nickel selenide nanoflower for robust electrocatalysis towards oxygen evolution

The state-of-the-art catalytic materials for oxygen evolution reaction (OER) are Ru and Ir precious metals. Despite of high activity in OER, large-scale production and application of these materials are restricted by low abundance and high price. Exploring inexpensive and efficient electrocatalytic materials for OER is a hot spot of research. Herein, Co-doped nickel selenide (Co–NiSe) nanoflowers are solvothermally in-situ grown on nickel foam (NF), which acts as a robust catalytic electrode for OER. In 1.0 M KOH electrolyte, the required overpotential is 380 mV to reach a current density of 100 mA cm−2. The Tafel slope is 111.0 mV dec−1. A long-term catalytic stability for OER is obtained. Cobalt doping not only produces more catalytically active sites for OER, but also promotes charge transport through electronic interaction with NiSe.

FeOOH/Ni heterojunction nanoarrays on carbon cloth as a robust catalyst for efficient oxygen evolution reaction

Developing catalysts based on transition metal-based materials for oxygen evolution reaction (OER), which are cheap and efficient, is one of the keys to increase the rate of electrolysis of water to produce hydrogen. Herein, we successfully synthesize iron hydr(oxy)oxide nano-arrays on carbon cloth (FeOOH@CC), and then metallic nickel is electrodeposited on its surface to fabricate FeOOH/Ni heterojunction nanoarrays. Notably, the optimal FeOOH/Ni heterojunction nanoarrays catalyst shows high electrocatalytic performance toward OER with a small overpotential of 257.8 mV at 50 mA cm−2, a Tafel slope of 30.8 mV dec−1 and outstanding long-term stability in alkaline media. The superior OER performance could be ascribed to the introducing of metallic nickel. The nickel in-situ grows on the surface of FeOOH, which not only can improve the conductivity of FeOOH, but also cooperate with FeOOH to form the FeOOH/Ni heterogeneous interfaces for further enhancing OER electrocatalytic activities. This work provides a simple and efficient strategy of interface engineering to fabricate oxyhydroxide/metal heterojunction nanoarrays as high-efficiency OER catalysts.

Fluorination of ZIF-67 framework templated Prussian blue analogue nano-box for efficient electrochemical oxygen evolution reaction

Efficient oxygen evolution nano-catalyst is significant for hydrogen generation in the water-splitting reaction. Herein, we demonstrate that fluorination of ZIF-67 Framework templated Prussian blue analogue hollow nano-box is highly efficient for the oxygen evolution reaction (OER). The structure and morphology observation shows the degree of structural transformation and morphology are influenced by the fluorination temperature, and the catalytic ability for OER is correspondingly correlated to these characters. The product obtained at the annealed temperature of 250 °C exhibits the highest catalytic performance for OER with an overpotential of 243 mV (No IR correction) to offer 10 mA cm−2 when loaded on the inert glass carbon electrode, which is much better than that of the commercial IrO2 catalysts. High catalytic stability and kinetics are also found for the OER. Moreover, it has the highest intrinsic activity as demonstrated by the specific activity and turnover frequency indicating the intrinsic advantages of fluorination and hollow nano-box structure. This study enriches the application of Prussian blue analogue based hollow materials for OER by facile fluorination at low temperatures.

Enhanced water oxidation activity of 3D porous carbon by incorporation of heterogeneous Ni/NiO nanoparticles

Considering the expensive and rare property of noble-metal based materials, great efforts are made to synthesize high-activity, economical and electrochemically stable catalyst for oxygen evolution reaction (OER) in harsh alkaline. Heterogeneous materials coupled by transition metal and carbon exhibit high capability for OER in recent years. Here, three-dimensional (3D) porous carbon coupled with Ni and NiO hybrid nanoparticles (Ni-Cx-y, x and y are annealing temperature and time, respectively) is synthesized via high temperature pyrolysis and air annealing treatment. Redox reaction between carbon atoms and nickel ions during synthesis could achieve a high-level graphitization, which greatly enhances the corrosion resistance of catalyst in alkaline solution. The overpotential at 10 mA cm−2 and Tafel slope of Ni-C500-20 achieve 353 mV and 97 mV dec–1, respectively. Increased defects and intrinsic activity induced by air annealing process and synergistic effect between carbon, Ni and NiO give rise to the enhanced OER performance of as-prepared catalyst, as confirmed by in-situ Raman spectra. The catalyst conforms to sustainable and economic development concept, being a potential material for OER.

Revealing the effect of phosphorus doping on Co@carbon in boosting oxygen evolution catalytic activity

Oxygen evolution reaction (OER) is a vital process in numerous energy conversion systems, and therefore, considerable attention has been devoted to the fabrication of nonnoble and highly efficient electrode materials for OER. Herein, Co nanoparticles embedded in the N, P-codoped porous carbon (Co/P-N-C) are synthesized using a novel Co-based metal-organic polymer (Co-MOP) as the precursor through carbonization and a subsequent phosphorization treatment process. When the phosphorization treatment is carried out at pH 3, Co/P-N-C exhibits a very low overpotential of 300 mV for a current density of 10 mA cm−2 with a small Tafel slope of 61 mV dec−1 and excellent stability over 20000 s. The electrocatalytic performance of Co/P-N-C was even better than that of the commercial RuO2 material. Density functional theory calculations were used to simulate the electrocatalytic process and to verify the experimental findings, which showed that the superior OER performance was attributed to the active sites of doped P and Co nanoparticles. This viable strategy of using a novel Co-MOP to create a novel phosphorized Co/P-N-C microporous carbon-based material may expand the opportunities for the exploration of high-performance and robust nonnoble metal electrocatalysts for energy-conversion reactions.

Confined Synthesis of Oriented Two-Dimensional Ni3(hexaiminotriphenylene)2 Films for Electrocatalytic Oxygen Evolution Reaction.

Metal-organic frameworks (MOFs) can provide atomically dispersed metal active coordination sites (M-NX, M-SX, and M-OX) for electrocatalytic reactions. Among them, MOFs with motif M-NX or analogues are expected to be promising active electrode materials for oxygen evolution reaction (OER). Contrary to bulk MOFs, two-dimensional (2D) MOFs usually have high surface areas, fully exposed active sites, and specific electrical properties. Herein, we constructed 2D Ni3(hexaiminotriphenylene)2 [Ni3(HITP)2] films on the electrode surface by utilizing the bottom-up liquid/liquid/gel tri-phase interface system and explored their potential applications in electrocatalytic OER. The thickness of the 2D Ni3(HITP)2 films can be controlled to be about 5 nm. The prepared 2D Ni3(HITP)2 films had oriented polycrystalline character and showed excellent performance in OER. A current density of 10 mA cm-2 for 3-layer Ni3(HITP)2 film electrodes was obtained at 1.62 V, which was 20 mV lower than that for the commercial IrO2 catalyst. Electrochemical tests and electrochemical impedance spectroscopy showed that better OER performance of 3-layer Ni3(HITP)2 films was ascribed to their high electrochemically active surface area, better kinetic process, and fast ion diffusion and transport.

Boosting oxygen evolution reaction performance by nickel substituted cobalt-iron oxide nanoparticles embedded over reduced graphene oxide

Designing non-precious-metal (NPM) electrocatalysts for oxygen evolution reaction (OER) from alkaline water is of paramount importance for clean, sustainable and conversion technologies. Herein, we report a facile, scalable and rapid microwave assisted synthesis to produce Ni substituted cobalt-iron oxides Co1-xNixFe2O4 (x = 0, 0.10, 0.25, 0.50, 0.75 and 1) supported over conductive reduced graphene oxide (rGO) and successfully employing them as electrode materials for OER in alkaline medium. Interestingly, by tuning Ni amount in cobalt-iron oxide has a profound influence on the OER activity i.e., Co0.75Ni0.25Fe2O4/rGO exhibits the best OER performance with an overpotential of 440 mV at 10 mA cm−2 and considerable electrochemical stability over 1000 cycles and even up to 10 h in 0.1 M KOH solution.

Synthesis of double perovskite La2MnNiO6 nanoparticles as highly efficient oxygen evolution electro-catalysts

Double perovskite La2MnNiO6 nanoparticles (approximately 30 nm in diameter) were synthesized using a modified sol-gel method followed by a firing process and used as promising electrode materials for oxygen evolution reactions (OERs). The phase purity of the nanoparticles was verified using X-ray diffraction and Raman spectroscopy measurements. La2MnNiO6 nanoparticles crystallize in a monoclinic structure (P21/n space group) with refined lattice parameters of a = 5.461(5) Å, b = 5.512(3) Å, c = 7.760(5) Å, and β = 90.10(2)°. The elemental composition, particle size, size distribution, and surface area of the La2MnNiO6 nanoparticles were also investigated. La2MnNiO6 nanoparticles are ferromagnetic in nature and exhibit hysteresis with a saturation magnetization value of approximately 9 emu/g. La2MnNiO6 nanoparticles exhibit highly efficient electro-catalytic activity for OERs with a low onset over-potential (approximately 65 mV) and low Tafel slope values (120 mV/dec) in alkaline media. The over-potential of La2MnNiO6 nanoparticles at a current density of 10 mA/cm2 is in good agreement with the reported over-potential (ƞ10) of double perovskites, commercial Pt/C and IrO2 electro-catalysts for promoting OERs.

Surface protonation and oxygen evolution activity of epitaxial La1−xSrxCoO3 thin films

As an alternative electrode material, transition metal oxides are promising candidates due to multivalent nature and oxygen vacancies present in the structure with facilitate redox reactions. The aim of this study is to explore the intrinsic mechanism of oxygen evolution reaction (OER) using two-dimensional thin film La1− x Sr x CoO3 electrode as a model. Herein, we report a planar two-dimensional model La1− x Sr x CoO3 electrode grown on a Nb-SrTiO3 single-crystal substrate via pulsed laser deposition. The two-dimensional La1− x Sr x CoO3 films offer different oxygen evolution activities at different pH electrolyte solutions. The mechanisms behind the variations of the oxygen evolution activity were discussed after comparing the oxygen evolution activity before and after treatments of the electrodes and measurements by various test methods. The results of this study offer a promising, low-cost electrode material for the efficient OER and a sustainable production of hydrogen fuel.

Nanocomposites of cobalt benzene tricarboxylic acid MOF with rGO: An efficient and robust electrocatalyst for oxygen evolution reaction (OER)

In this work, electrocatalytic studies of highly active and non-precious metal based Cobalt benzene tricarboxlic acid (Co BTC) metal organic framework (MOF) and its reduced graphene oxide (rGO) composites for oxygen evolution reaction (OER) were performed in an alkaline media by employing cyclic voltammetry. Cobalt based MOF and their rGO composites were solvothermally synthesized. Prepared samples were further characterized for structural and morphological analysis through X-rays diffraction (XRD), scanning electron microscopy (SEM), Fourier transform Infrared (FTIR) spectroscopy and Energy dispersive spectroscopy (EDX) techniques. During CV studies the main emphasis was to observe the effect of rGO concentration on electrochemical response of synthesized materials for OER. Co BTC-5 wt % rGO (Cobalt benzene tricarboxlic acid-reduced graphene oxide) composite with current density of 10 mA/cm2 at over potential 0.29 V vs. RHE proved to be a potential candidate due to its high activity and stability for OER.

Formation of Porous Nanotubes for Simultaneous Improvements of Material Usage Efficiency and Catalytic Performance of Iridium-Based Water Oxidation Reaction Catalysts

Iridium (Ir) is the most widely used material for oxygen evolution reaction (OER) catalyst due to its great catalytic performance. However, Iridium is a very expensive element because it is one of the rarest elements on earth. Therefore, it is necessary to minimize Iridium consumption whilst maintaining the highest possible catalytic performance. One of common strategies to achieve a high catalytic performance is enlarging surface area by forming nanostructures; however, such nanostructures often limit mass transport of both reactants (liquid electrolyte) and products (oxygen gas), nullifying the benefit gained from the large surface area. Here, we developed a porous nanotube catalyst structure which can maximize its performance with a very small amount of Iridium and allow facile mass transport via pores formed on the sidewall of the nanotubes. The synthesis involves the formation of vertically aligned ZnO nanowires that serve as a template. Electrodeposition of Ni follows to conformally coat the ZnO nanowires. Careful control of wet etching conditions results in the complete removal of ZnO and partial removal of Ni shells forming pores on the Ni nanotubes. Finally, Ir is electrodeposited on the porous Ni nanotubes. The porosity of the structure can be controlled to optimize the catalytic performance. It can also be used as a catalyst template for other elements that need high performance while using a small amount of the material. The details of the synthesis and the electrochemical measurements of OER using our nanostructured Ir-based catalysts will be presented.

Operando Raman Spectroscopy Reveals Cr-Induced-Phase Reconstruction of NiFe and CoFe Oxyhydroxides for Enhanced Electrocatalytic Water Oxidation

Nonprecious NiFe, CoFe oxyhydroxide are among the most active materials for oxygen evolution reaction (OER) in basic media. However, phase separation in these composites during water oxidation rema...

Coordination polymers as heterogeneous catalysts in hydrogen evolution and oxygen evolution reactions.

The efficiency of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in the process of electrochemical water oxidation will determine the competence for mass distributions of sustainable energy conversion technologies in the future. Recently, coordination polymers (CPs)/metal-organic frameworks (MOFs) have emerged as desirable hybrid materials for catalysing electrochemical energy conversion processes due to their unique advantages, such as crystalline porous structure, high surface area, and diverse and tunable chemical components. This feature article briefly summarizes the recent part of the fast growing literature on electrocatalysis by pristine MOF/CPs, MOF composites, as well as post-synthetically modified materials for HER, OER and overall water splitting reactions. The article highlights the contributions of various authors in this area and aims to provide a consolidated idea regarding the engineering strategies and composition-structure-activity relationships of these pristine CP based materials for such electrocatalytic applications.

Copper nickel alloy nanorods textured nanoparticles for oxygen evolution reaction

Facile and low-cost synthesis routes of highly competent catalyst materials for applications in oxygen evolution reaction are imperative. In this work, we synthesised bimetallic alloy crystals using nickel nitrate as a metal ions source and trimesic acid as an organic linker. Further annealing at an elevated temperature under a nitrogen atmosphere yielded alloy nanorods textured nanoparticles. Numerous characterization techniques were used, revealing the bimetallic nature of the synthesised product. The product was a highly efficient and stable material for oxygen evolution reaction (OER) in an alkaline medium. In 1.0 M KOH solution, the copper nickel alloy with graphitic carbon (Cu3.8Ni@C) catalyst showed remarkable OER activity, obtaining an overpotential of 233 mV at a current density of 10 mA cm−2 with stability up to 18 h under continuous electrolysis. Consequently, we believe that this work could contribute insights into low-cost electrocatalysts for OER.

Self-supported hierarchical CoFe-LDH/NiCo2O4/NF core-shell nanowire arrays as an effective electrocatalyst for oxygen evolution reaction

Design and synthesis of three-dimension (3D) nanowire arrays (NWAs) electrocatalyst with a core-shell structure have been considered as an efficient way to enhance the performances for the oxygen evolution reaction (OER). In this work, novel hierarchical CoFe-LDH/NiCo2O4/Ni foam (CoFe-LDH/NCO/NF) core-shell nanowire arrays have been fabricated via a facile two-step strategy. The as-obtained nanocomposites were characterized by multiple methods, and their electrocatalytic properties for OER have also been evaluated. The unique structural and component features for the as-prepared 3D nanocomposites facilitate the enhancement of the OER performances. CoFe-LDH/NCO/NF nanocomposites display an excellent OER electrocatalytic activity with a low overpotential of 273 mV at 20 mA cm−2, as well as an outstanding long-term electrochemical stability with a 90% current preservation during a 32 h test. The remarkable electrocatalytic performances of the CoFe-LDH/NCO/NF electrode ascribe to the strong synergistic effect between the NiCo2O4 (NCO) nanowires core and the CoFe-LDH nanosheets shell at the interface. Our work provides a novel sight on the rational design of 3D core/shell nanoarrays electrode materials for OER.

Graphene oxide decorated bimetal (MnNi) oxide nanoflakes used as an electrocatalyst for enhanced oxygen evolution reaction in alkaline media

Precious non-noble metals have been constantly attracting research attention in order to realize an inexpensive, extra active and more stable electrocatalysts in terms of various oxidation states and structures for their applications in oxidation (splitting) of water. In the present work graphene oxide incorporated, MnO2-NiO composite metal oxide nanoflakes were synthesized on the stainless steel substrate using efficient electrodeposition route in alkaline media and drop casting method with further annealing treatment at 400 °C for 4 h. Initially MnO2-NiO nanoflakes were deposited using different cyclic sweep rates, later graphene oxide suspension was drop casted on the MnO2-NiO nanoflakes and subsequently subjected to annealing at 200 °C for 2 h. The prepared electrode material is denoted as GO/MnO2-NiO/SS and used as an electrocatalyst for oxygen evolution. Field emission scanning electron microscopy, transmission electron microscopy, Energy dispersive electron spectroscopy and X-ray diffraction spectroscopy were used to study the crystalline nature and morphologies of the deposited films. The electrochemical properties of the electrode material were investigated using cyclic voltammetry and linear sweep voltammetry. The electrode exhibits low overpotential and small Tafel slope of 379 mV and 47.84 mVdec−1 at the current density of 10 mA cm−2 in alkaline (KOH) medium. In addition, the electrode shows a long time stability of 28800 s. Hence, the present study suggests that the GO incorporated Mn-Ni bimetal oxide modified electrode is suitable electrode material for oxygen evolution reaction (OER), owing to its facile preparation, inexpensive, easy handling and high active nature.