Electrocatalytic Performance For Oxygen Evolution Reaction Research Articles

Application of heteroatom doping strategy in electrolyzed water catalytic materials

• Mainly reviews the design and synthesis methods of the latest heteroatom-doped water electrolysis catalysts. • Focusing on the design, synthesis strategies and the mechanism of improving catalytic activity. • The reaction mechanism of water electrolysis at different pH and general methods for evaluating catalytic performance are briefly reviewed. The development of clean and renewable new energy to solve the shortage of fossil energy and environmental pollution is an important research direction in the future. Hydrogen energy has been regarded as a kind of future energy because of its excellent characteristics of pollution-free and high calorific value. In addition, the electrolyzed water technology can also be combined with renewable energy sources such as solar energy to achieve complete recycling of hydrogen energy. In actual production, the realization of efficient water splitting relies to a large extent on the low-cost, high-activity and durable hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) reaction catalysts. Recently, heteroatom-doped transition metal-based water electrolysis catalyst materials have shown excellent electrocatalytic performance and durability for HER and OER, showing great potential for replacing precious metal-based catalysts. This article reviews the application of heteroatom doping strategies in transition metal-based catalytic materials and their latest research progress. First, summarize the internal relationship of heteroatom doping strategy to the morphology and catalytic activity of electrolyzed water catalytic materials. Then, the preparation process of heteroatom-doped transition metal-based catalytic materials for water electrolysis and the reasons for the improved performance and related mechanisms are discussed. Finally, the opportunities and challenges for the future development of heteroatom-doped transition metal-based catalytic materials are emphasized from the perspectives of catalytic mechanism and improvement measures.

Advances in anion vacancy for electrocatalytic oxygen evolution reaction

• Anion vacancy plays a critical role in determining the activity of catalysts. • Anion vacancy engineering can modify the electronic structure and improve the intrinsic activity. • Some advanced methods for the effective anion vacancy engineering are summarized. • The challenges and future directions of anion vacancy engineering are discussed. Electrocatalytic oxygen evolution reaction (OER), as a central process of many important energy conversion devices, is a very dynamic process. Understanding the characteristics of the materials that affect OER performance is of vital significance for the development of more advanced OER electrocatalysts. Anion vacancy engineering, with the functions of improving the intrinsic activity, exposing more accessible surface active sites, improving electrical conductivity and mechanical stability, plays an extra role in enhancing the electrocatalytic OER performance of transition metal compounds. Although the great endeavors made, the intrinsic reaction mechanism and dynamic behavior of anion vacancy sites are still unclear. Therefore, studying the structure–activity relationship of defective electrocatalysts is favorable for gaining a better understanding on the specific reaction mechanism and dynamic behavior. Herein, in this review, a systematic overview of the effect of anion vacancies, such as oxygen, sulfur, phosphorous, selenium vacancies on electrocatalytic OER performance of transition metal compounds is summarized, along with some advanced synthetic strategies and characterizations. Moreover, the challenges and future directions of anion vacancies engineering toward OER are also briefly discussed.

Defect and Interface Engineering of Three-Dimensional Open Nanonetcage Electrocatalysts for Advanced Electrocatalytic Oxygen Evolution Reaction.

Defect engineering and interface engineering are two efficient approaches to promote the electrocatalytic performance of transition metal oxides (TMOs) by modulating the local electronic structure and inducing a synergistic effect but usually require costly and complicated processes. Herein, a facile electrochemical etching method is proposed for the controllable tailoring of the defects in a three-dimensional (3D) open nanonetcage CoZnRuOx heterostructure via the in situ electrochemical etching to remove partial ZnO. The highly open 3D nanostructures, numerous defects, and multicomponent heterointerfaces endow the CoZnRuOx nanonetcages with more accessible active sites, moderated local electronic structure, and strong synergistic effect, thereby enabling them to not only deliver an ultralow overpotential (244 mV @ 10 mA cm-2) for oxygen evolution reaction (OER) but also high-performance overall water electrolysis by coupling with commercial Pt/C, with a potential of 1.52 V at 10 mA cm-2. Moreover, experiments and characterizations also reveal that the remaining Zn2+ can facilitate OH- adsorption and charge transfer, which also further improves the electrocatalytic OER performance. This work proposes a promising strategy for creating surface defects in heterostructured TMOs and provides insights to understand the defect- and interface-induced enhancement of OER electrocatalysis.

Local photothermal and photoelectric effect synergistically boost hollow CeO2/CoS2 heterostructure electrocatalytic oxygen evolution reaction

Solar-assisted electrocatalytic oxygen evolution reaction (OER) plays a key role in energy conversion and storage technology. Herein, we provide the novel design and synthesis of an advanced category of CeO2/CoS2 heterostructures, which combines the local photothermal effect (LPTE) action of CeO2 and the photoelectric effect CoS2 to boost OER. Interestingly, the hollow framework, rich heterointerface, coupled local photothermal effect and photoelectric effect equip CeO2/CoS2 with remarkably excellent electrocatalytic OER performance. As a result, the optimized CeO2/CoS2-6 only needs an overpotential of 283 mV to reach 10 mA cm−2 as well as a smaller Tafel slop of 33.2 mV dec-1, outperforming the RuO2 catalyst (323 mA @ 10 mA cm−2). Upon combination of experimental data and mechanistic study, it is revealed that the enhanced OER performance is primarily ascribed to the photo-induced local thermal. partly resulting from photoelectric effect, where the photogenerated electron flow from CeO2 to CoS2 can photogenerated holes in CeO2 to boost water oxidation. This work is extremely expected to offer a novel avenue for the rational design and fabrication of outstanding OER electrocatalysts upon LPTE.

Interface-Coupling of NiFe-LDH on Exfoliated Black Phosphorus for the High-Performance Electrocatalytic Oxygen Evolution Reaction.

Electrochemical oxygen evolution reaction (OER) always plays an important role in many electrochemical energy storage and conversion systems. Owing to the slow kinetics mainly brought from multiple proton-coupled electron transfer steps, the design and exploit low-cost, highly active, durable OER electrocatalysts are of significant importance. Although the black phosphorus (BP) shows good electrocatalytic OER performance, it still faces the problems of poor intrinsic activity and low stability due to its instability under ambient conditions. The NiFe-LDH was assembled onto the surfaces of exfoliated BP (EBP) nanoflakes to realize the interfacial coupling between them, achieving an effective improvement in electrocatalytic activity and stability. Benefitting from the interfacial P-O bonding, the NiFe-LDH@EBP hybrid shows high OER activity with a low overpotential of ∼240 mV@10 mA cm−2 toward OER under alkaline conditions, as well as the good stability. Density functional theory (DFT) calculations proved that the interface-coupling of NiFe-LDH on BP promotes charge transfer kinetics and balances the adsorption/desorption of reaction intermediates, ultimately imparting excellent OER electrocatalytic activity.

Flower-shaped Fe–CoP@C composites derived from MOFs as an efficient electrocatalyst for oxygen evolution reaction

<p indent="0mm">Sluggish kinetics of oxygen evolution reaction (OER) dramatically hampers the large-scale application of electrochemical water splitting. It is of great importance to develop efficient and stable non-precious metal catalysts for OER. Using a hydrothermal-ion-exchange-high-temperature-phosphating approach, a novel 3D micron-flower-shaped composite (Fe–CoP@C) with strong coupling of iron-doped cobalt phosphide and carbon-based material was firstly prepared based on flower-like Co₃O₄@Co–MOF precursors. Fe–CoP nanoparticles loaded on functionalized carbon nanosheets can facilitate sufficient contact with the electrolyte and expose more catalytic active sites. The incorporation of Fe optimizes the electronic structure of the material and enables the material to exhibit excellent OER activity. In an alkaline electrolyte, Fe–CoP@C catalysts manifest superior electrocatalytic performance for OER with an overpotential of 259 mV at <sc>10 mA cm⁻²,</sc> a Tafel slope of 48.24 mV dec⁻¹. Benefiting from the strong coupling between nanoparticles and the carbon layer, the catalysts also exhibit faster reaction kinetics and higher structural stability. The composites display excellent long-term stability, with 108 h of continuous operation in alkaline solutions.

Molecular Regulation Based on Functional Trimetallic Metal-Organic Frameworks for Efficient Oxygen Evolution Reaction.

Metal-organic frameworks (MOFs) as classic crystalline porous materials have attracted great interest in the catalytic field. However, how to realize molecular regulation of the MOF structure to achieve a remarkable oxygen evolution reaction (OER) electrocatalyst is still a challenge. Herein, we designed several series of special MOF materials to explore the relationship between the structure and properties as well as the related reactive mechanism. First, various metal centers, including Fe, Co, Ni, Zn, and Mg, were utilized to construct the first series of trimetallic MOF materials, namely, M3-MOF-BDC, where BDC = 1,4-benzenedicarboxylic acid, also known as terephthalic acid. Among of them, Fe3-MOF-BDC shows the best OER performance and only needs an overpotential of 312 mV at 10 mA cm-2. Then, functional BDC-X ligands (X = NH2, OH, NO2, DH) with various characteristic groups were selected to construct a new series, namely, Fe3-MOF-BDC-X, to further improve its OER electrocatalytic performance. As expected, Fe3-MOF-BDC-NH2 exhibited a greatly enhanced OER performance with ultralow Tafel slopes of 45 mV dec-1 and overpotentials of 280 mV at 10 mA cm-2 when the BDC-NH2 ligand was adopted, even superior to commercial IrO2 (323 mV) and most of the reported pristine MOFs as OER electrodes. Much higher structural stability was proven. The detailed structure-property relationship and mechanism are discussed. In a word, this work provides a very important theoretical basis for the design and exploration of new MOF electrocatalysts.

High-Performance A-Site Deficient Perovskite Electrocatalyst for Rechargeable Zn–Air Battery

Zinc–air batteries are one of the most excellent of the next generation energy devices. However, their application is greatly hampered by the slow kinetics of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) of air electrode. It is of great importance to develop good oxygen electrocatalysts with long durability as well as low cost. Here, A-site deficient (SmSr)0.95Co0.9Pt0.1O3 perovskites have been studied as potential OER electrocatalysts prepared by EDTA–citrate acid complexing method. OER electrocatalytic performance of (SmSr)0.95Co0.9Pt0.1O3 was also evaluated. (SmSr)0.95Co0.9Pt0.1O3 electrocatalysts exhibited good OER activities in 0.1 M KOH with onset potential and Tafel slope of 1.50 V and 87 mV dec−1, similar to that of Ba0.5Sr0.5Co0.8Fe0.2O3 (BSCF-5582). Assembled rechargeable Zn–air batteries exhibited good discharge potential and charge potential with high stability, respectively. Overall, all results illustrated that (SmSr)0.95Co0.9Pt0.1O3 is an excellent OER electrocatalyst for zinc–air batteries. Additionally, this work opens a good way to synthesize highly efficient electrocatalysts from A-site deficient perovskites.

Development of Electrolyzer Using NiCo(OH)2 Layered Double Hydroxide Catalyst for Efficient Water Oxidation Reaction.

Over the past decade, layered double hydroxides (LDH) have been the subject of extensive investigations owing to their remarkable water splitting catalytic activity. Stability and porosity are several of the features of LDH which help them to serve as efficient oxygen evolution reaction (OER) catalysts. Based on these considerations, we synthesized NiCo(OH)2 LDH and probed its OER electrocatalytic performance. The synthesized catalyst was subjected to X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy for structural analysis and investigation of its surface morphology, surface composition, and oxidation states. The LDH-NiCo(OH)2 was anchored over the FTO surface and the fabricated electrode was found to exhibit a much lower OER onset potential of 265 mV, a much higher current density of 300 mAcm−2 and a smaller Tafel slope of 41 mVdec−1. Moreover, the designed catalyst was found to be stable up to 2500 repeated voltametric scans. These figures of merit regarding the structure and performance of the designed LDH are expected to provide useful insights into the fundamental understanding of the OER catalysts and their mechanisms of action, thus enabling the more rational design of cost effective and highly efficient electrocatalysts for use in water splitting.

A tin‐incorporated multi‐phase perovskite nanocomposite for efficiently catalyzing oxygen evolution reaction

The rational design of effective and specific catalysts for oxygen evolution reaction (OER) is of vital importance for the implementation of electrochemical water oxidation as a sustainable route to produce hydrogen. Perovskite oxides have attracted considerable interests in view of the highly tunable structural, electronic, and catalytic properties associated with their compositions. Herein, an efficient Sn-incorporated nominal perovskite nanocomposite, SrCo0.7Sn0.3O3−δ (SCS), derived from a facile one-pot self-assembly process, is designed as an outstanding electrocatalyst to catalyze OER in alkaline conditions. Benefiting from the unique structure, increased active oxygen intermediates, and favorable electrical conductivity, the optimized SCS exhibits superior OER electrocatalytic performance, including low overpotential of only 309 mV at 10 mA cm−2, fast kinetics with a small Tafel slope of 56 mV dec−1, and 72-fold improvement in mass activity and 108-fold enhancement in specific activity relative to the pristine SrCoO3−δ catalyst. The SCS catalyst also demonstrates excellent OER durability with negligible potential fluctuation for 30 hours continuous operation. This work highlights a promising strategy to develop high-performance perovskite nanocomposites to perform efficient OER electrocatalysis.

Oxygen vacancy-rich amorphous FeNi hydroxide nanoclusters as an efficient electrocatalyst for water oxidation

In this work, a one-pot strategy is presented to directly synthesize amorphous FexNiy hydroxide nanoclusters (denoted as ANC-FexNiy, <2 nm) with oxygen vacancies induced by ionic liquids. The ANC-FexNiy catalyst presents abundant catalytic sites and high intrinsic conductivity. As such, the optimized ANC-Fe1Ni2 exhibits high activity in oxygen evolution reaction (OER) with a Tafel slope of 39 mV dec–1 and an overpotential of 266 mV at 10 mA cm−2. Notably, the optimized ANC-Fe1Ni2 shows an extraordinarily large mass activity of 3028 A gFeNi–1 at the overpotential of 300 mV, which is ∼24-fold of commercial RuO2 catalyst. The superior activity of these FexNiy hydroxide nanoclusters is ascribed to (i) the amorphous and distorted structure with abundant oxygen vacancies, and (ii) enhanced active site density by downsizing the ANC-FexNiy clusters. This strategy provides a novel route for enhancing OER electrocatalytic performance and highly encouraging for the future application of amorphous metal hydroxides in catalysis.

Engineering the Electronic Structures of Metal-Organic Framework Nanosheets via Synergistic Doping of Metal Ions and Counteranions for Efficient Water Oxidation.

Metal-organic framework (MOF) nanosheets with attractive chemical and structural properties have been considered as prominent oxygen evolution reaction (OER) electrocatalysts, while the insufficient exposed active sites and low electrical conductivity of MOFs limit their electrocatalytic activity and further industrial applications. Herein, a unique strategy to remarkably boost electrocatalytic OER activity of one Ni-based MOF is developed by the simultaneous incorporation of Fe3+ ions and BF4- anions within its layer structure. The optimized electrocatalyst NiFe-MOF-BF4--0.3 NSs shows superior OER activity with a required ultralow overpotential of 237 mV at 10 mA cm-2, a small Tafel slope of 41 mV dec-1, and outstanding stability in an alkaline medium. The experimental and density functional theory (DFT) calculation results verify that the interactions between metal (M) ions and BF4- anions (defined as M···F, M = Ni or Fe) in this catalyst can adjust the adsorption abilities of oxygen intermediates and lower the free energy barrier of the potential-determining step by tailoring its electronic structure, thereby remarkably boosting its OER activity. This protocol provides new insights into surface and structure engineering of 2D MOFs, leading to greatly enhanced electrocatalytic OER performance.

Iron single-atom catalysts confined in covalent organic frameworks for efficient oxygen evolution reaction

The exploration of environmentally friendly and highly efficient oxygen evolution reaction (OER) catalysts is vital to large-scale, electrochemical renewable-fuels generation. Here, we report an iron single-atom catalyst (SAC) confined in a covalent organic framework (Fe-SAC@COF), which constitutes an unusual Fe–NO coordination in the skeleton. The as-prepared Fe-SAC@COF exhibits a high mass activity of 9.20 A mg −1 , which is 1.95 times higher than Ni species of the same coordination and 5.05 times higher than nanoparticulate Fe counterpart. Moreover, it shows, to the best of our knowledge, a record-low overpotential (290 mV) and Tafel slope (40 mV dec −1 ) among the reported atomically dispersed Fe-based catalysts and surpasses the benchmark Ir/C catalyst. The density functional theory calculation shows that the Fe–NO coordination exhibits low binding energy of oxygenated intermediates, which leads to an outstanding electrocatalytic OER performance. This work provides design strategies toward unusually coordinated SACs by prudent COF confinement for advanced electrocatalysis. • Iron single atoms are confined in covalent organic frameworks • Specific Fe–NO coordination is verified • Iron single-atom catalysts show notable oxygen evolution activity Wang et al. report single-atom iron catalysts confined in covalent organic frameworks with an unusual Fe–NO coordination mode. They exhibit notable electrocatalytic performance for oxygen evolution.

Ni3S2 nanostrips@FeNi-NiFe2O4 nanoparticles embedded in N-doped carbon microsphere: An improved electrocatalyst for oxygen evolution reaction

The designing and preparing of low-cost and easily available electrocatalyst for oxygen evolution reaction (OER) are crucial for many advanced energy technologies. Herein, the Ni3S2 nanostrips@FeNi-NiFe2O4 nanoparticles embedded in N-doped carbon (Ni3S2@FeNi-NiFe2O4/C) microspheres were synthesized as improved electrocatalyst for OER, using a facile heat-treatment method. The optimized Ni3S2@FeNi-NiFe2O4/C-3 sample exhibits enhanced electrocatalytic activity toward OER performance with an overpotential of 280 mV at 10 mA cm−2 and a small Tafel slope of 33.9 mV dec−1. Furthermore, Ni3S2@FeNi-NiFe2O4/C-3 composite shows good stability in alkaline media. The outstanding electrocatalytic OER performance of composites was attributed due to the synergetic effect between Ni3S2 nanostrips and FeNi-NiFe2O4 nanoparticles and it is believed that the heterointerfaces between them act as active centers for OER. Additionally, N-doped carbon prevents the aggregation of Ni3S2@FeNi-NiFe2O4 species and enhances the conductivity of composites during the OER process.

Boosting the Electrocatalytic Activity of Nickel-Iron Layered Double Hydroxide for the Oxygen Evolution Reaction byTerephthalic Acid

The development of a new type of oxygen evolution reaction (OER) catalyst to reduce the energy loss in the process of water electrolysis is of great significance to the realization of the industrialization of hydrogen energy storage. Herein, we report the catalysts of NiFe double-layer hydroxide (NiFe-LDH) mixed with different equivalent terephthalic acid (TPA), synthesized by the hydrothermal method. The catalyst synthesized with the use of the precursor solution containing one equivalent of TPA shows the best performance with the current density of 2 mA cm−2 at an overpotential of 270 mV, the Tafel slope of 40 mV dec−1, and excellent stable electrocatalytic performance for OER. These catalysts were characterized in a variety of methods. X-ray diffraction (XRD), Fourier Transform Infrared Spectrometer (FTIR), and Raman spectrum proved the presence of TPA in the catalysts. The lamellar structure and the uniform distribution of Ni and Fe in the catalysts were observed by a scanning electron microscope (SEM) and a transmission electron microscope (TEM). In X-ray photoelectron spectroscopy (XPS) of NiFe-LDH with and without TPA, the changes in the peak positions of Ni and Fe spectra indicate strong electronic interactions between TPA and Ni and Fe atoms. These results suggest that a certain amount of TPA can boost catalytic activity.

Laser in situ synthesis of NiFe2O4 nanoparticle-anchored NiFe(OH)x nanosheets as advanced electrocatalysts for the oxygen evolution and urea oxidation reactions

The in situ growth of oxygen-vacancy-rich hybrid electrocatalysts with a high surface area is considered to be an effective strategy for enhancing the oxygen evolution reaction (OER) and urea oxidation reaction (UOR) performance. However, in situ synthesis is often difficult due to multistep procedures and harsh conditions. Herein, NiFe2O4 nanoparticles are successfully grown in situ on NiFe(OH)x nanosheets via using unique laser ablation in liquids technology. The quenching effect of the pulsed laser and the reduction of BH4− promote the generation of oxygen-vacancy-abundant NiFe(OH)x/NiFe2O4 nanocomposites, and the weak alkalinity of the NaBH4 solutions accelerates the production of NiFe(OH)x nanosheets. Profited from the affluent oxygen vacancies and enhancive surface areas, the NiFe(OH)x/NiFe2O4 nanocomposites reveal enhancement in electrocatalytic OER performance with small overpotential of 249 mV at 10 mA cm−2 and a Tafel slope of 40.1 mV dec−1, accompanied by superior stability (the current density retention after 150 h is 98.5% of the initial value). In addition, the NiFe(OH)x/NiFe2O4 hybrid electrocatalysts also exhibit excellent electrocatalytic performance for the urea oxidation reaction (a potential of 1.343 V at 10 mA cm−2 and a Tafel slope of 19.9 mV dec−1). This work can provide guidance for exploring other hydroxide/oxide materials with abundant oxygen vacancies and high surface areas.

Bifunctional Ni-Fe/NiMoNx nanosheets on Ni foam for high-efficiency and durable overall water splitting

Fabricating bifunctional electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is challengeable. Herein, an efficient and durable bifunctional Ni-Fe/NiMoNx electrocatalyst has been synthesized on nickel foam. This electrocatalytic system exhibits significant HER and OER performances with overpotentials of 49 and 260 mV at 20 mA cm−2, respectively. For overall water splitting, Ni-Fe/NiMoNx electrodes require only 1.54 V for 10 mA cm−2. This enhanced HER and OER electrocatalytic performance is due to the combined effect of multiple active components formed after NH3 treatment. This work provides a new strategy for the rational design of bifunctional electrocatalysts for overall water splitting.

Hybrid electrocatalyst of CoFe2O4 decorating carbon spheres for alkaline oxygen evolution reaction

The exploration of highly effective, durable, and affordable electrocatalysts for the oxygen evolution reaction (OER) is vital in developing an alkaline electrolyzer for H 2 generation. Although binary transition metal oxides, particularly spinel ferrites with a general chemical formula MFe 2 O 4, are a promising class of candidates for OER, their intrinsically low electrical conductivity has a significant negative impact on their electrochemical performances. Herein, we report a simple one-step method for tailoring carbon spheres (CSs) with CoFe 2 O 4 (CFO) to form a CFO@CSs composite as a cost-effective electrocatalyst. The as-synthesized CFO@CSs features a high specific surface area of 56.94 m 2 /g and exhibits decently high OER catalytic activity with a relatively small overpotential of 390 mV at 10 mA/cm 2 , fast kinetics, and high durability in alkaline medium. Moreover, the pairing of the bare Ni mesh electrode as the cathode and the CFO@CSs on Ni mesh as the anode is set up to illustrate its feasibility for the overall alkaline water splitting. This study offers a cost-effective electrocatalyst for OER that can be used instead of precious metals in various renewable energy storage and conversion applications. CoFe 2 O 4 @carbon spheres nanohybrid (CFO@CSs) electrocatalyst was successfully prepared with a facile one-step solvothermal method, which shows excellent electrocatalytic OER performance with low overpotentials of 390 mV at 10 mA cm −2 OER. The assembled system CFO@CSs/NM||bare NM also shows good catalytic performance and excellent stability of the overall water splitting in alkaline media.

Dynamic dissolution and re-adsorption of molybdate ion in iron incorporated nickel-molybdenum oxyhydroxide for promoting oxygen evolution reaction

Transition metal-based pre-catalysts undergo drastic reconstruction to form the active catalysts during the alkaline oxygen evolution reaction (OER). However, the effect of escaped inactive ion from pre-catalysts themselves is usually ignored during reconstruction processes. Here, we investigate the effect of inactive MoO42- escaped from a pre-catalyst of Fe incorporated nickel-molybdenum oxyhydroxide (NiMo-Fe) on OER performance. The results of in-situ Raman and X-ray photoelectron spectroscopy reveal that MoO42- can be easily dissolved into KOH electrolyte and re-adsorbed on surface of catalyst during OER processes, which delivers a promoting effect on OER performance. The dissolution of MoO42- is beneficial for increasing the reconstruction degree of NiMo-Fe to form the active phase of NiFeOOH. Theoretical calculations demonstrate that the re-adsorbed MoO42- is favorable for the adsorption of the OOH* intermediate, thus boosts the OER activity. As expected, the NiMo-Fe shows a superior electrocatalytic performance for OER, outperforming the pre-catalyst without Mo species. This finding enriches the knowledge of inactive-ion effect on alkaline OER performance and offers a path for developing efficient electrocatalysts.

A Superior and Stable Electrocatalytic Oxygen Evolution Reaction by One-Dimensional FeCoP Colloidal Nanostructures.

Transition metal phosphides (TMPs) are expected to be excellent electrocatalysts for oxygen evolution reaction (OER) because of their high stability, highly conducting metalloid nature, highly abundant constituting elements, and the ability to act as a precatalyst due to in situ surface-formed oxy-hydroxide species. Herein, a "one-pot" colloidal approach has been used to develop a rod-shaped one-dimensional non-noble metal FeCoP electrocatalyst, which exhibits an excellent OER activity with an exceptionally high current density of 950 mA cm-2, a turnover frequency value of 7.43 s-1, and a low Tafel slope value of 54 mV dec-1. The FeCoP electrocatalyst affords OER ultralow overpotentials of 230 and 260 mV at current densities of 50 and 100 mA cm-2, respectively, in 1.0 M KOH, and demonstrates a superior catalytic stability of 10,000 cycles and durability up to 60 h at 50 mA cm-2. An insight into the superior and stable electrocatalytic OER performance by the FeCoP nanorods is obtained by extensive X-ray photoelectron spectroscopy, X-ray diffraction, Raman and infrared spectroscopy, and cyclic voltammetry analyses for a mechanistic study. This reveals that a high number of electrocatalytically active sites enhance the oxygen evolution and kinetics by offering metal ion sites for utilitarian in situ surface formation and adsorption of *O, *OH, and *OOH reactive species for OER catalysis.