Amorphous Nanocages of Cu‐Ni‐Fe Hydr(oxy)oxide Prepared by Photocorrosion For Highly Efficient Oxygen Evolution

Cai, Zhi; Li, Lidong; Zhang, Youwei; Yang, Zhao; Yang, Jie; Guo, Yingjie; Guo, Lin

doi:10.1002/anie.201812601

Cited by 200 publications

(107 citation statements)

References 25 publications

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“…Where R s is the series resistance of the system. All potentials measurements were converted to the reversible hydrogen electrode (RHE) based on the following formula: The reaction overpotential (η) was calculated according to the following formula: h V ð Þ ¼ E RHE À 1:23 (9) Long-term stability cyclic voltammetry tests were performed in alkaline solution (1 M KOH) at room temperature at a scan rate of 100 mV s À 1 , carbon paper electrode were used as working electrode with a loading amount about 0.2 mg cm À 2 . Electrochemical impedance spectroscopy (EIS) measurements were performed at an applied potential of 0.7 V (vs. Hg/HgO) in the frequency range of 100 kHz to 0.01 Hz.…”

Section: Electrochemical Measurementsmentioning

confidence: 99%

“…[6] Yunmin Zhu et al exhibited that controlling oxygen vacancies in PrBa 0.5 Sr 0.5 Co 1.5 Fe 0.5 O 5 + δ (PBSCF) can significantly improve in OER performance. In addition, cationic metal doping [9] and supported nanomaterials [10] have also been widely recognized to tune electronic structure, resulting in a synergistic effect from metal ions and metal-support interactions. Moreover, the catalyst surface state during OER is still a non-negligible factor in catalyst design process.…”

Section: Introductionmentioning

confidence: 99%

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Tuning Surface Electronic Structure of Two‐Dimensional Cobalt‐Based Hydroxide Nanosheets for Highly Efficient Water Oxidation

et al. 2020

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Highly exposing active sites and well tuning their electronic configuration are great challenges toward highly efficient oxygen evolution reaction (OER) catalysts. Herein, we demonstrate an in situ surface modification strategy for α and β-Co (OH) 2 nanosheets to boost their OER activities via a simple substitution of their surface hydroxyl functional groups by carboxylate or acetic anhydridate ones, respectively. This in situ surface modification can increase the areal densities of active sites and reduce the OER energy barriers while maintaining initial structure and morphology. Experimental results show that the modified catalysts can present much larger electro-chemical active surface area (ECSA) and lower OER onset overpotential in comparison with the fresh ones. In case of carboxylate-modified α-Co(OH) 2 nanosheets, the onset overpotential has decreased from 266 to 233 mV and the required overpotential at 10 mA cm À 2 has decreased from 309 to 288 mV on glassy carbon electrode. Density of states (DOS) calculations reveal an optimized adsorption energy of reaction intermediates. Remarkably, tuning surface electronic structure of catalyst by appropriately choosing highly electronegative functional groups can be considered as an efficient approach to enhance its OER activity.

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Section: Electrochemical Measurementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Tuning Surface Electronic Structure of Two‐Dimensional Cobalt‐Based Hydroxide Nanosheets for Highly Efficient Water Oxidation

et al. 2020

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“…Considering that all the three samples (FeCo(Mn)−O/NF, FeCoMn/NF and FeCo−O/NF) were prepared from the analogous procedures, the incorporation of Mn species has significantly tuned the crystal phase of the resulting product, inducing crystalline‐to‐amorphous structural conversion. The amorphous FeCo(Mn)−O/NF can potentially decrease the grain boundaries resistance and maximize the exposure of accessible active sites …”

Section: Figurementioning

confidence: 99%

“…The amorphous FeCo(Mn)À O/NF can potentially decrease the grain boundaries resistance and maximize the exposure of accessible active sites. [9,26,27] Scanning electron microscopy (SEM) images reveal that surface of the bare NF is uniformly covered with nanoclusters of FeCo(Mn)À O ( Figure S1). The direct growth of FeCo(Mn)À O on the conductive substrate has enabled good mechanical adhesion, promoted the contact with electrolyte and reduced both the mass and charge transfer resistance.…”

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confidence: 99%

Nickel Foam‐Supported Amorphous FeCo(Mn)−O Nanoclusters with Abundant Oxygen Vacancies through Selective Dealloying for Efficient Electrocatalytic Oxygen Evolution

Wang

et al. 2020

ChemElectroChem

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Developing earth‐abundant, cost‐effective and high‐performance electrocatalyst towards the oxygen evolution reaction (OER) is a great challenge for large‐scale hydrogen production from electrochemical water splitting. Nickel‐foam‐supported amorphous hierarchical nanoclusters of metal/metal (hydr)oxides with abundant oxygen defects (FeCo(Mn)−O/NF) were prepared from an FeCoMn/NF precursor through chemical dealloying. The FeCo(Mn)−O/NF electrode exhibits enhanced OER activity in alkaline electrolyte with an overpotential of only 235 mV to drive a current density of 10 mA cm−2, a small Tafel slope of 44.5 mV dec−1 and excellent durability over 100 h. The superior OER performance is attributed to the synergistic effect of abundant oxygen vacancies, hierarchical morphology and amorphous structure, which essentially modulate the electronic structures and create more active sites. These interesting findings highlight the significance of dealloying strategy on the structural defects and improved catalytic performance of the electrocatalysts.

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“…In comparison with crystal materials, amorphous materials have the following characteristics. First, amorphous materials have long‐range disorder and short‐range order intrinsic structural characteristics and possess rich defects and active sites . Second, the chemical composition of amorphous materials can be regulated in a wide range, thereby fine tuning the electronic structure of catalysts.…”

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Amorphous Intermediate Derivative from ZIF‐67 and Its Outstanding Electrocatalytic Activity

Zhou

Zheng

Tang

et al. 2019

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137

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Increasing the amount of active sites and enhancing their intrinsic activity are two basic strategies for designing electrocatalytic materials. [3,18] Nanostructured electrocatalytic materials have been extensively studied because of their high specific surface area. [6,9,10] Amorphous materials have also been widely explored in the field of electrocatalysis because of their specific structure and property. [19][20][21][22][23] In comparison with crystal materials, amorphous materials have the following characteristics. First, amorphous materials have long-range disorder and short-range order intrinsic structural characteristics and possess rich defects and active sites. [19][20][21][22][23][24][25] Second, the chemical composition of amorphous materials can be regulated in a wide range, [26] thereby fine tuning the electronic structure of catalysts. Third, amorphous materials possess isotropic property and can provide homogenous active sites during chemical reaction, [27] thereby favoring the regulation of reactant selectivity. Lastly, amorphous materials are usually prepared under mild conditions, which are conducive to the large-scale application of these materials. [28] Metal-organic frameworks (MOFs) are novel coordination compound materials with periodic and porous structures in which metal cations act as a coordination center and organic molecules serve as ligands. [29][30][31][32][33][34][35][36][37][38] Various MOF-derived materials, such as metal oxides, metal sulfides, and metal/carbon composites, have been prepared by heat treatment, hydrothermal/solvothermal treatment, or other treatment approaches for an MOF precursor. [39][40][41][42][43][44][45] The composition, morphological characteristics, and structure of MOF-derived materials can be effectively regulated. [39,40] MOF-derived materials can maintain the structural diversity and porosity characteristics of MOFs and effectively improve their conductivity and stability. [39,40] The structure and chemical property of MOF-derived materials can be regulated by MOF precursor design and treatment control. [39,40] Therefore, MOF-derived materials have good application prospects in electrochemical energy storage, electrochemical energy conversion, and electrochemical sensors. [46][47][48][49] As a typical representative of zeolitic imidazolate framework MOF material, ZIF-67 has been extensively studied as a precursor for derivative preparation. [50] Moreover, ZIF-67 derivatives have received more and more attentions in the field of electrocatalysis. [51][52][53][54][55][56] In the present study, an amorphous intermediate derivative was prepared using a ZIF-67 hollow sphere (HS-ZIF-67) as a precursor via low-temperature heat treatment Increasing active sites is an effective method to enhance the catalytic activity of catalysts. Amorphous materials have attracted considerable attention in catalysis because of their abundant catalytic active sites. Herein, a series of derivatives is prepared via the low-temperature heat treatment of ZIF-67 hollow sphere at ...

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Amorphous Nanocages of Cu‐Ni‐Fe Hydr(oxy)oxide Prepared by Photocorrosion For Highly Efficient Oxygen Evolution

Cited by 200 publications

References 25 publications

Tuning Surface Electronic Structure of Two‐Dimensional Cobalt‐Based Hydroxide Nanosheets for Highly Efficient Water Oxidation

Tuning Surface Electronic Structure of Two‐Dimensional Cobalt‐Based Hydroxide Nanosheets for Highly Efficient Water Oxidation

Nickel Foam‐Supported Amorphous FeCo(Mn)−O Nanoclusters with Abundant Oxygen Vacancies through Selective Dealloying for Efficient Electrocatalytic Oxygen Evolution

Amorphous Intermediate Derivative from ZIF‐67 and Its Outstanding Electrocatalytic Activity

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