scholarly journals Oxygen evolution reaction: Bifunctional mechanism breaking the linear scaling relationship

2020 ◽  
Vol 152 (10) ◽  
pp. 104712 ◽  
Author(s):  
Patrick Gono ◽  
Alfredo Pasquarello
Keyword(s):  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Linear Scaling ◽  
Bifunctional Mechanism ◽  
Scaling Relationship

scholarly journals A Bifunctional Iron Nickel Catalyst for the Oxygen Evolution Reaction

2018 ◽  
Author(s):  
fang song ◽  
Michael Busch ◽  
Benedikt Lassalle-Kaiser ◽  
Chia-Shuo Hsu ◽  
Elitsa Petkucheva ◽  
...  
Keyword(s):  
Oxygen Evolution ◽  
Transition Metal Oxides ◽  
Oxygen Evolution Reaction ◽  
Density Functional ◽  
Maximum Activity ◽  
Binding Energies ◽  
Alkaline Solutions ◽  
Bifunctional Mechanism ◽  
Scaling Relationship ◽  
Covalently Linked

The oxygen evolution reaction (OER) is a key process that enables the storage of renewable energies in the form of chemical fuels. Although numerous transition metal oxides have been explored as OER catalysts, the scaling relationship of the binding energies of various surface-bound intermediates imposes a limit on the maximum activity of these oxides. While previous computational studies have suggested bifunctional catalysts might be capable of overcoming this limit, stable and non-precious catalysts of this type remain elusive. Here, we describe a catalyst that exhibits activity significantly higher than current state-of-the-art catalysts that operate in alkaline solutions, including the benchmark nickel iron oxide. This new catalyst is both easy to prepare and stable for many hours. Operando X-ray absorption spectroscopic data reveal that the catalyst is made of nanoclusters of gamma-FeOOH covalently linked to the edge sites of a gamma-NiOOH support. According to density functional theory computations, this structure allows a reaction path involving iron as the oxygen evolving center and a nearby terrace O site on the gamma-NiOOH support oxide as a hydrogen acceptor. This bifunctional mechanism circumvents the aforementioned maximum activity limit associated with the scaling relationship and leads to superior OER activity.<br>

scholarly journals A Bifunctional Iron Nickel Catalyst for the Oxygen Evolution Reaction

2018 ◽  
Author(s):  
fang song ◽  
Michael Busch ◽  
Benedikt Lassalle-Kaiser ◽  
Chia-Shuo Hsu ◽  
Elitsa Petkucheva ◽  
...  
Keyword(s):  
Oxygen Evolution ◽  
Transition Metal Oxides ◽  
Oxygen Evolution Reaction ◽  
Density Functional ◽  
Maximum Activity ◽  
Binding Energies ◽  
Alkaline Solutions ◽  
Bifunctional Mechanism ◽  
Scaling Relationship ◽  
Covalently Linked

The oxygen evolution reaction (OER) is a key process that enables the storage of renewable energies in the form of chemical fuels. Although numerous transition metal oxides have been explored as OER catalysts, the scaling relationship of the binding energies of various surface-bound intermediates imposes a limit on the maximum activity of these oxides. While previous computational studies have suggested bifunctional catalysts might be capable of overcoming this limit, stable and non-precious catalysts of this type remain elusive. Here, we describe a catalyst that exhibits activity significantly higher than current state-of-the-art catalysts that operate in alkaline solutions, including the benchmark nickel iron oxide. This new catalyst is both easy to prepare and stable for many hours. Operando X-ray absorption spectroscopic data reveal that the catalyst is made of nanoclusters of gamma-FeOOH covalently linked to the edge sites of a gamma-NiOOH support. According to density functional theory computations, this structure allows a reaction path involving iron as the oxygen evolving center and a nearby terrace O site on the gamma-NiOOH support oxide as a hydrogen acceptor. This bifunctional mechanism circumvents the aforementioned maximum activity limit associated with the scaling relationship and leads to superior OER activity.<br>

scholarly journals Spectroscopic and Electrokinetic Evidence for a Bifunctional Mechanism of the Oxygen Evolution Reaction

2020 ◽  
Author(s):  
Lichen Bai ◽  
seunghwa lee ◽  
Xile Hu
Keyword(s):  
Hydrogen Atom ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Hydrogen Atom Transfer ◽  
Atom Transfer ◽  
Oxygen Intermediates ◽  
Bifunctional Mechanism ◽  
Bond Forming ◽  
Highly Active ◽  
Scaling Relationship

The oxygen evolution reaction (OER) is an essential anodic reaction in many energy storage processes. OER is most often proposed to occur via a mechanism involving four consecutive proton-coupled electron transfer (PCET) steps, which imposes a performance limit due to the scaling relationship of various oxygen intermediates. A bifunctional OER mechanism, in which the energetically demanding step of the attack of hydroxide on a metal oxo unit is facilitated by a hydrogen atom transfer to a second site, has the potential to circumvent the scaling relationship. However, the bifunctional mechanism has hitherto only been supported by theoretical computations. Here we describe an operando Raman spectroscopic and electrokinetic study of two highly active OER catalysts, FeOOH-NiOOH and NiFe layered double hydroxide (LDH). The data support two distinct mechanisms for the two catalysts: FeOOH-NiOOH operates by a bifunctional mechanism where the rate-determining O-O bond forming step is the OH- attack on a Fe=O coupled with a hydrogen atom transfer to a NiIII-O site, whereas NiFe LDH operates by a conventional mechanism of four consecutive PCET steps. The experimental validation of the bifunctional mechanism enhances the understanding of OER catalysts.<br>

scholarly journals Spectroscopic and Electrokinetic Evidence for a Bifunctional Mechanism of the Oxygen Evolution Reaction

2020 ◽  
Author(s):  
Lichen Bai ◽  
seunghwa lee ◽  
Xile Hu
Keyword(s):  
Hydrogen Atom ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Hydrogen Atom Transfer ◽  
Atom Transfer ◽  
Oxygen Intermediates ◽  
Bifunctional Mechanism ◽  
Bond Forming ◽  
Highly Active ◽  
Scaling Relationship

The oxygen evolution reaction (OER) is an essential anodic reaction in many energy storage processes. OER is most often proposed to occur via a mechanism involving four consecutive proton-coupled electron transfer (PCET) steps, which imposes a performance limit due to the scaling relationship of various oxygen intermediates. A bifunctional OER mechanism, in which the energetically demanding step of the attack of hydroxide on a metal oxo unit is facilitated by a hydrogen atom transfer to a second site, has the potential to circumvent the scaling relationship. However, the bifunctional mechanism has hitherto only been supported by theoretical computations. Here we describe an operando Raman spectroscopic and electrokinetic study of two highly active OER catalysts, FeOOH-NiOOH and NiFe layered double hydroxide (LDH). The data support two distinct mechanisms for the two catalysts: FeOOH-NiOOH operates by a bifunctional mechanism where the rate-determining O-O bond forming step is the OH- attack on a Fe=O coupled with a hydrogen atom transfer to a NiIII-O site, whereas NiFe LDH operates by a conventional mechanism of four consecutive PCET steps. The experimental validation of the bifunctional mechanism enhances the understanding of OER catalysts.<br>

scholarly journals Spectroscopic and Electrokinetic Evidence for a Bifunctional Mechanism of the Oxygen Evolution Reaction

2020 ◽  
Author(s):  
Lichen Bai ◽  
seunghwa lee ◽  
Xile Hu
Keyword(s):  
Hydrogen Atom ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Hydrogen Atom Transfer ◽  
Atom Transfer ◽  
Oxygen Intermediates ◽  
Bifunctional Mechanism ◽  
Bond Forming ◽  
Highly Active ◽  
Scaling Relationship

The oxygen evolution reaction (OER) is an essential anodic reaction in many energy storage processes. OER is most often proposed to occur via a mechanism involving four consecutive proton-coupled electron transfer (PCET) steps, which imposes a performance limit due to the scaling relationship of various oxygen intermediates. A bifunctional OER mechanism, in which the energetically demanding step of the attack of hydroxide on a metal oxo unit is facilitated by a hydrogen atom transfer to a second site, has the potential to circumvent the scaling relationship. However, the bifunctional mechanism has hitherto only been supported by theoretical computations. Here we describe an operando Raman spectroscopic and electrokinetic study of two highly active OER catalysts, FeOOH-NiOOH and NiFe layered double hydroxide (LDH). The data support two distinct mechanisms for the two catalysts: FeOOH-NiOOH operates by a bifunctional mechanism where the rate-determining O-O bond forming step is the OH- attack on a Fe=O coupled with a hydrogen atom transfer to a NiIII-O site, whereas NiFe LDH operates by a conventional mechanism of four consecutive PCET steps. The experimental validation of the bifunctional mechanism enhances the understanding of OER catalysts.<br>

Engineering NiO/NiFe LDH Intersection to Bypass Scaling Relationship for Oxygen Evolution Reaction via Dynamic Tridimensional Adsorption of Intermediates

2019 ◽  
Vol 31 (11) ◽  
pp. 1804769 ◽  
Author(s):  
Zhi‐Wen Gao ◽  
Jie‐Yu Liu ◽  
Xue‐Min Chen ◽  
Xue‐Li Zheng ◽  
Jing Mao ◽  
...  
Keyword(s):  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Scaling Relationship

An Fe-doped NiTe bulk crystal as a robust catalyst for the electrochemical oxygen evolution reaction

2019 ◽  
Vol 55 (63) ◽  
pp. 9347-9350 ◽  
Author(s):  
Lei Zhong ◽  
Yufei Bao ◽  
Xu Yu ◽  
Ligang Feng
Keyword(s):  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Bulk Crystal ◽  
Stable Performance ◽  
Electrochemical Oxygen

An Fe doped NiTe bulk crystal was demonstrated to exhibit an extremely active and stable performance for the electrochemical oxygen evolution reaction.

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