NiFe水滑石纳米片阵列负载Ru用于提升碱性电催化析氢和析氧性能

通过离子交换的方式将Ru负载到NiFe水滑石（LDH）纳米阵列表面得到（Ru/NiFe LDH）,Ru的引入显著提升了NiFe LDH的活性比表面积,暴露了更多的活性位点,同时调控了其电子结构,大大提升了其本征催化活性。在碱性条件下,催化析氢反应时仅需50 mV的过电位即可达到10 mA·cm^-2的电流密度,Tafel斜率为52.3 mV·dec^-1。而相同条件下原始NiFe LDH达到10mA·cm^-2的电流密度则需要226 mV的过电位,Tafel斜率为157.5 mV·dec^-1。同时制备的Ru/NiFe LDH也展现出了良好的析氧催化活性,在50 mA·cm^-2的电流密度下,过电位仅为231 mV,而NiFe LDH则需237 mV。Ru/NiFe LDH在长时间的电催化条件下依然能保持良好的工作稳定性。     

Bimetallic two-dimensional materials for electrocatalytic oxygen evolution

Electrocatalytic oxygen evolution reaction(OER) is one of the important half reactions of electrocatalytic water splitting. However, the slow kinetic process involving four-electron transfer severely limits its reaction efficiency, which in turn limits the overall electrocatalytic hydrolysis efficiency. In order to improve the activity of the electrocatalytic OER, researchers mainly update the catalyst from three aspects,that is, increase the conductivity of the electrocatalyst, and the quantity...     

Carambola-like metal-organic frameworks for high-performance electrocatalytic oxygen evolution reaction

Hydrogen production by electrocatalytic water splitting promises a green and sustainable technology to address serious energy crisis and environmental pollution [1]. As well known, the process of electrocatalytic water splitting is composed of two half reaction, i.e. oxygen evolution reaction (OER) at the anode and hydrogen evolution reaction (HER) at the cathode [2].     

One-step synthesis of Fe-Ni hydroxide nanosheets derived from bimetallic foam for efficient electrocatalytic oxygen evolution and overall water splitting

For the first time, the Fe-Ni LDH nanosheets were prepared through simple one-step hydrothermal treatment of Fe-Ni bimetallic foam both as the substrate and Fe/Ni sources. The ratio of Ni/Fe elements played the important role in realizing the optimal catalytic activities for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). An alkaline water electrolyzer was constructed with the Fe-Ni hydroxide nanosheets/Fe-Ni alloy foam-60% Fe as anode and Ni(OH)₂/Fe-Ni alloy foam-25% Fe as cathode, which displays superior electrolytic performance (affording 10 mA/cm² at 1.62 V) and lasting durability.     

Transition metal carbides in electrocatalytic oxygen evolution reaction

Oxygen evolution reaction(OER) is admitted to an important half reaction in water splitting for sustainable hydrogen production.The sluggish four-electron process is known to be the bottleneck for enhancing the efficiency of OER.In this regard,tremendous efforts have been devoted to developing effective catalysts for OER.In addition to Ir-or Ru-based oxides taken as the benchmark,transition metal carbides have attracted ever-increasing interest due to the high activity and stability as low-cost OER electrocatalysts.In this review,the transition metal carbides for water oxidation electrocatalysis concerning design strategies and synthesis are briefly summarized.Some typical applications for various carbides are also highlighted.Besides,the development trends and outlook are also discussed.     

Heterostructured composite of NiFe-LDH nanosheets with Ti4O7 for oxygen evolution reaction

Developing oxygen evolution reaction (OER) electrocatalyst based on earth-abundant materials holds great promise for ascertaining water-splitting to surmount its deprived kinetics. In this regard, NiFe-LDH (layered double hydroxide) receives considerable attention owing to their layered structure. However, they still suffer from poor electronic conductivity and structural stability. We combined NiFe-LDH nanosheets with Magnéli phase Ti₄O₇ into a heterostructured composite. A series of analyses reveal that decorating Ti₄O₇ facilitates charge transfer to enhance the conductivity of NiFe-LDH-Ti₄O₇. During electrochemical measurement, Ni²⁺ is transformed to metastable Ni³⁺ (Ni (OH)→ NiOOH) before the OER onset potential. Thus, the presence of Ni³⁺ as the main active sites could improve the chemisorption of OH^? to facilitate OER. As a result, the NiFe-LDH-Ti₄O₇ catalyst delivers as low as onset potential (1.43 V). Combining the holey structure (NiFe-LDH and Ti₄O₇) and the defect engineering generated on NiFe-LDH-Ti₄O₇ as a synergistic effect improves the OER performance. The inclusion of Ti₄O₇ in the composite leads to more vacancy sites, as evidenced by the extended X-ray absorption fine structure (EXAFS) analysis. The obtained defective structure with a low coordination environment would improve the electronic conductivity and facilitate the adsorption process of H₂O onto metal cations, thereby increasing the intrinsic catalytic activity of NiOOH. The strong coupling of NiFe-LDH and Ti₄O₇ also increases the stability, and the heterostructured composite helps maintain the structural robustness of the LDH.     

Electrodeposition of poly-NiFe-alizarin red S complex for efficient electrocatalytic oxygen evolution reactions

Journal of Solid State Electrochemistry - A novel NiFeA/CPE has been fabricated by electrodepositing poly-Ni (II)-Fe (III)-alizarin red (NiFeA) complex on the surface of carbon paste electrode...     

金属-氧共价性增强的缺陷态高熵岩盐型氧化物用于电催化析氧

高熵材料可以在单一晶相中引入五种或五种以上元素以优化电子结构和配位环境,可作为一类新兴的电催化剂.本文制备了一种岩盐型高熵氧化物Mg0.2Co0.2Ni0.2Cu0.2Zn0.2O(HEO)用于催化氧析出反应(OER).由于相邻的不同金属离子晶格失配,所制备的HEO具有丰富的缺陷.此外,电负性更小的Mg和Zn元素的存在...     

Active facet determination of layered double hydroxide for oxygen evolution reaction

Oxygen evolution reaction(OER)plays an indispensable role in developing renewable clean energy resources.One of the critical bottlenecks for the reaction is the...     

CoP@SiO2nanoreactors: A core-shell structure for efficient electrocatalytic oxygen evolution reaction

Metallic phosphides as a crucial class of metal-like compounds show high electric conductivity and electrochemical properties. It is of significant benefit to understanding the relationship between the electrocatalytic performance and phosphating degree of precursors. In this work, using Co₃O₄@SiO₂ as precursor, core-shell structured CoP@SiO₂ nanoreactors with outstanding oxygen evolution reaction performance were synthesized through a facile calcination method. The electrocatalytic performance of CoP@SiO₂ modified electrode that treated with 500 mg NaH₂PO₂ was greatly enhanced. The obtained product displays a low overpotential of 280 mV at a current density of 10 mA/cm² and a Tafel value 89 mV/dec in alkaline conditions. The easy available CoP@SiO₂ with outstanding catalytic performance and stability possesses huge potential in future electrochemical applications.     

硼、磷共掺杂铁钴双金属材料的制备及其电催化析氧性能

采用一步水热法合成了硼、磷共掺杂铁钴材料(Fe-Co-B-P)。借助扫描电子显微镜(SEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)、傅里叶变换红外光谱(FT-IR)等技术对所合成材料的形貌、结构和组成进行表征。利用线性扫描伏安(LSV)、循环伏安(CV)、电化学阻抗谱(EIS)等技术研究材料电化学析氧反应(OER)性能。结果表明,Fe-Co-B-P表面疏松且粗糙,颗粒间有许多空隙。在电流密度为10和100 mA·cm^-2时,其过电势分别为278和309 mV,Tafel斜率为24 mV·dec^-1,说明该材料具有较优的电催化析氧性能。其在连续进行10 h的计时电位测试过程中,电势基本保持在1.55 V (vs RHE),表明该催化剂具有较好的电化学稳定性。这是由于铁钴双金属与硼、磷非金属之间的协同作用促进了电子的传递。     

硼、磷共掺杂铁钴双金属材料的制备及其电催化析氧性能

采用一步水热法合成了硼、磷共掺杂铁钴材料(Fe-Co-B-P)。借助扫描电子显微镜(SEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)、傅里叶变换红外光谱(FT-IR)等技术对所合成材料的形貌、结构和组成进行表征。利用线性扫描伏安(LSV)、循环伏安(CV)、电化学阻抗谱(EIS)等技术研究材料电化学析氧反应(OER)性能。结果表明,Fe-Co-B-P表面疏松且粗糙,颗粒间有许多空隙。在电流密度为10和100 mA·cm^-2时,其过电势分别为278和309 mV,Tafel斜率为24 mV·dec^-1,说明该材料具有较优的电催化析氧性能。其在连续进行10 h的计时电位测试过程中,电势基本保持在1.55 V(vs RHE),表明该催化剂具有较好的电化学稳定性。这是由于铁钴双金属与硼、磷非金属之间的协同作用促进了电子的传递。     

Electrosynthesis of hierarchical NiLa-layered double hydroxide electrode for efficient oxygen evolution reaction

Oxygen evolution reaction(OER) is a key process for electrochemical water splitting due to its intrinsic large overpotential. Recently, layered double hydroxides(LDHs), especially Ni Fe-LDH, have been regarded as highly performed electrocatalysts for OER in alkaline condition. Here we first present a new class of Ni La-LDH electrocatalyst synthesized by an electrochemical process for efficient water splitting. The as-prepared NiL a-LDH nanosheet arrays(NSAs) give remarkable electrochemical activity and durability under alkaline environments, with a low overpotential of 209 mV for OER to deliver a current density of 10 mA cm~(-2), surpassing most of previous reported LDHs eletrocatalysts. The presence of NiLa-LDH in this work extends the studies about LDHs-based electrocatalysts, which will benefit the development of electrochemical energy storage and conversion systems.     

Tetrazole-functionalized two-dimensional covalent organic frameworks coordinated with metal ions for electrocatalytic oxygen evolution reaction

The search for functionalized covalent organic framework (COF) materials is significant on account of their great promise for frontline applications in various fields. Herein, a novel and convenient tactic is developed to design and fabricate the tetrazole-functionalized COF materials with abundant nitrogen atoms, which can provide active sites, facilitating the incorporation of COFs with metal ions. In particular, a β-ketoenamine-linked COF named COF-TpDb is selected as precursor for postsynthetic modification to introduce the tetrazole moieties to coordinate with metal ions cobalt (Co²⁺) and palladium (Pd²⁺), giving two functional metal-coordinated COFs complexes COF-TpDb-TZ-Co and COF-TpDb-TZ-Pd. The resultant COF-TpDb-TZ-Co displays a higher oxygen evolution reaction activity with a lower overpotential of 390 mV at a current density of 10 mA cm^?2, which is much enhanced compared with COF-TpDb-TZ. The tactic for the fabrication of tetrazole-functionalized COFs with abundant nitrogen atoms implements rational design for the construction of functional COFs and expands the promising application of metal-coordinated COF materials in electrocatalysis.     

PVP-assisted synthesis of porous CoO prisms with enhanced electrocatalytic oxygen evolution properties

Hollow metal oxide materials with nanometer-to-micrometer dimensions have attracted tremendous attention because of their potential applications in energy conversion and storage systems. Numerous efforts have been focused on developing versatile methods for the rational synthesis of various hollow structures to act as efficient water oxidation catalysts. In this work, a unique porous and hollow CoO tetragonal prism-like structure has been successfully synthesized via a facile and efficient co-precipitation method with polyvinylpyrrolidone(PVP K30) followed by a heating treatment of the resulted precipitates.The as-prepared porous and hollow CoO microprisms displayed a high activity and stability for water oxidation in 1.0 M KOH solution. To reach a current density of 10 m A/cm~2, a low overpotential of 280 m V is required. The remarkable activity can be attributed to the synergistic effect between two different but well-distributed CoO crystalline phases, uniform particle size, ameliorative crystallinity, high surface area and the low mass transfer resistance benefitted from the unique porous structure.     

Highly exposed NiFeOx nanoclusters supported on boron doped carbon nanotubes for electrocatalytic oxygen evolution reaction

The development of efficient and cost-effective electrocatalysts for oxygen evolution reaction (OER) is crucial for the overall water splitting. Herein, we prepared a highly exposed NiFeO_x ultra-small nanoclusters supported on boron-doped carbon nonotubes catalyst, which achieves a 10 mA/cm² anodic current density at a low overpotential of 213 mV and the Tafel slope of 52 mV/dec in 1.0 mol/L KOH, superior to the pristine NiFeO_x-CNTs and other state-of-the-art OER catalysts in alkaline media. A combination study (XPS, sXAS and XAFS) verifies that the local atomic structure of Ni and Fe atoms in the nanoclusters are similar to NiO and Fe₂O₃, respectively, and the B atoms which are doped into the crystal lattice of CNTs leads to the optimization of Ni 3d e_g orbitals. Furthermore, in-situ X-ray absorption spectroscopies reveal that the high valence state of Ni atoms are served as the real active sites. This work highlights that the precise control of highly exposed multicomponent nanocluster catalysts paves a new way for designing highly efficient catalysts at the atomic scale.     

Ternary NiCoFe-layered double hydroxide hollow polyhedrons as highly efficient electrocatalysts for oxygen evolution reaction

正With exhaustion of fossil fuels and the deterioration of global environment,widespread and intensive researches have been concentrated on clean and sustainable alternative energy sources,such as metal-air batteries ~([1]),fuel cells ~([2]) and water splitting devices [3].Electrocatalytic oxidation of water to O_2 (oxygen     

Nickel iron carbonate hydroxide hydrate decorated with CeOx for highly efficient oxygen evolution reaction

Journal of Solid State Electrochemistry - Highly active, durable, and inexpensive nanostructured catalysts are crucial for achieving efficiently and economically electrochemical water splitting. In...     

碱性介质中碳纳米管FeNi复合物上电催化析氧反应(英文)

Non-noble metals such as Fe and Ni have comparable electrocatalytic activity and stability to that of Ir and Ru in an oxygen evolution reaction (OER). In this study, we synthesized carbon nanofibers with embedded FeNi composites (FeNi-CNFs) as OER electrocatalysts by a facile route comprising electrospinning and the pyrolysis of a mixture of metal precursors and a polymer solution. FeNi-CNFs demonstrated catalytic activity and stability that were better than that of 20 wt% Ir on Vulcan carbon black in oxidizing water to produce oxygen in an alkaline media. Physicochemical and electrochemical characterization revealed that Fe and Ni had synergistic roles that enhanced OER activity by the uniform formation and widening of pores in the carbon structure, while the CNF matrix also contributed to the increased stability of the catalyst.     

Ternary layered double hydroxide oxygen evolution reaction electrocatalyst for anion exchange membrane alkaline seawater electrolysis

Anion exchange membrane(AEM) water electrolyzers are promising energy devices for the production of clean hydrogen from seawater. However, the lack of active and robust electrocatalysts for the oxygen evolution reaction(OER) severely impedes the development of this technology. In this study, a ternary layered double hydroxide(LDH) OER electrocatalyst(NiFeCo-LDH) is developed for high-performance AEM alkaline seawater electrolyzers. The AEM alkaline seawater electrolyzer catalyzed by the NiFeCo L...