Spectroscopic identification of active sites for the oxygen evolution reaction on iron-cobalt oxides

Smith, Rodney D. L.; Pasquini, Chiara; Loos, Stefan; Chernev, Petko; Klingan, Katharina; Kubella, Paul; Mohammadi, Mohammad Reza; González-Flores, Diego; Dau, Holger

doi:10.1038/s41467-017-01949-8

Cited by 174 publications

(193 citation statements)

References 45 publications

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“…Understanding the role of Fe in these catalysts is important to elucidate design principles. Operando X‐ray absorption spectroscopy (XAS) has been used to probe the atomic and electronic structure of catalysts during the OER to understand the nature of the catalytic active site . Friebel et al .…”

Section: Figurementioning

confidence: 99%

Operando X‐Ray Absorption Spectroscopy Shows Iron Oxidation Is Concurrent with Oxygen Evolution in Cobalt–Iron (Oxy)hydroxide Electrocatalysts

et al. 2018

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Iron cations are essential for the high activity of nickel and cobalt-based (oxy)hydroxides for the oxygen evolution reaction, but the role of iron in the catalytic mechanism remains under active investigation. Operando Xray absorption spectroscopya nd density functional theory calculations are used to demonstrate partial Fe oxidation and ashortening of the FeÀObond length during oxygen evolution on Co(Fe)O x H y .C obalt oxidation during oxygen evolution is only observed in the absence of iron. These results demonstrate adifferent mechanism for water oxidation in the presence and absence of iron and support the hypothesis that oxidized iron species are involved in water-oxidation catalysis on Co-(Fe)O x H y .

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Section: Figurementioning

confidence: 99%

Operando X‐Ray Absorption Spectroscopy Shows Iron Oxidation Is Concurrent with Oxygen Evolution in Cobalt–Iron (Oxy)hydroxide Electrocatalysts

et al. 2018

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“…Moreover, the Fourier transform (FT)‐EXAFS curve of Co 0.7 Fe 0.3 CB‐A exhibits an obvious scattering feature CoO bond at 1.47 Å, which provides the fingerprint of di‐µ‐oxo bridged cobalt octahedral (Figure 4b). Notably, the less coordination number of CoCo (at 2.46 Å) backscattering pair on Co 0.7 Fe 0.3 CB‐A, compared to the CoCo in standard CoOOH, indicates that CoO x motif located at the edges or corners of CoOOH or defects may exist in Co 0.7 Fe 0.3 CB‐A sample.…”

Section: Resultsmentioning

confidence: 99%

Physically Adsorbed Metal Ions in Porous Supports as Electrocatalysts for Oxygen Evolution Reaction

Liu

Shen

et al. 2020

Adv Funct Materials

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Developing highly efficient and earth‐abundant electrocatalysts for the oxygen evolution reaction (OER) is significantly important for water‐splitting. Here, for the first time it is reported that the physically adsorbed metal ions (PAMI) in porous materials can be served as highly efficient OER electrocatalysts, which provides a universal PAMI method to develop electrocatalysts. This PAMI method can be applied to almost all porous supports, including graphene, carbon nanotubes, C3N4, CaCO3, and porous organic polymers and all the systems exhibit excellent OER performance. In particular, the as‐synthesized Co0.7Fe0.3CB exhibits a small overpotential of 295 mV and 350 mV at the current density of 10 mA cm−2 and 100 mA cm−2, respectively, which exceeds commercial 40 wt% IrO2/CB and most reported non‐noble metal‐based OER catalysts. Moreover, the mass activity of Co0.7Fe0.3CB reaches 643.4 A g−1 at the overpotential of 320 mV, which is nearly 4.7 times higher than that of 40 wt% IrO2/CB. In addition, the advanced ex situ and in situ synchrotron X‐ray characterizations are carried out to unravel the PAMI synthetic process. In short, this PAMI method will break the conversional understanding, i.e., the most OER catalysts are synthesized chemically, because the new PAMI method does not require any chemical synthesis, which therefore opens a new avenue for the development of OER electrocatalysts.

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“…Chemical etching agents can also be applied to particles to remove certain atoms on the surface of particles to create defects. Although this process destroys the crystalline structure of the material, defects created through this method are mostly on the surface . Recent studies have also shown that the intrinsic site activity of catalyst active sites can significantly affect overall catalytic performances.…”

Section: Approaches To Enhancing the Activitymentioning

confidence: 99%

A review of transition metal‐based bifunctional oxygen electrocatalysts

Ibrahim

Tsai

Chala

et al. 2019

J Chinese Chemical Soc

105

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Electrochemical energy storage and conversion devices play a key role in the development of clean, sustainable, and efficient energy systems to meet the sustainable growth of our society. However, challenging issues including the sluggish kinetics of oxygen electrode reactions involving the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) are present, limiting the implementation of devices such as metal‐air batteries, water electrolyzers, and regenerative fuel cells. In this review, various monometallic and bimetallic transition metal oxides (TMOs) and hydroxides are summarized in terms of their application for ORR/OER, in which the merits and demerits of various precious metal and carbon‐based metal oxide materials are discussed, with requirements for better electrocatalysts and catalyst support being introduced as well. Following this, different approaches to improve catalytic activity such as the introduction of doping and defects, the manipulation of crystal facets, and the engineering of supports, compositions, and morphologies are summarized in which TMOs with improved ORR/OER catalytic activities can be synthesized, further improving the speed, stability, and polarization of electrochemical energy storage and conversion devices. Finally, perspectives into the improvement of performance and the better understanding of ORR/OER mechanisms for bifunctional electrocatalysts using in situ spectroscopic techniques and density functional theory calculations are also discussed.

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Spectroscopic identification of active sites for the oxygen evolution reaction on iron-cobalt oxides

Cited by 174 publications

References 45 publications

Operando X‐Ray Absorption Spectroscopy Shows Iron Oxidation Is Concurrent with Oxygen Evolution in Cobalt–Iron (Oxy)hydroxide Electrocatalysts

Operando X‐Ray Absorption Spectroscopy Shows Iron Oxidation Is Concurrent with Oxygen Evolution in Cobalt–Iron (Oxy)hydroxide Electrocatalysts

Physically Adsorbed Metal Ions in Porous Supports as Electrocatalysts for Oxygen Evolution Reaction

A review of transition metal‐based bifunctional oxygen electrocatalysts

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