scholarly journals 3D atomic-scale imaging of mixed Co-Fe spinel oxide nanoparticles during oxygen evolution reaction

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Weikai Xiang ◽  
Nating Yang ◽  
Xiaopeng Li ◽  
Julia Linnemann ◽  
Ulrich Hagemann ◽  
...  
Keyword(s):  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Active Sites ◽  
3D Structure ◽  
Three Dimensional ◽  
Atom Probe ◽  
Vital Role ◽  
Atomic Scale ◽  
Hydroxyl Groups ◽  
Compositional Distribution

AbstractThe three-dimensional (3D) distribution of individual atoms on the surface of catalyst nanoparticles plays a vital role in their activity and stability. Optimising the performance of electrocatalysts requires atomic-scale information, but it is difficult to obtain. Here, we use atom probe tomography to elucidate the 3D structure of 10 nm sized Co2FeO4 and CoFe2O4 nanoparticles during oxygen evolution reaction (OER). We reveal nanoscale spinodal decomposition in pristine Co2FeO4. The interfaces of Co-rich and Fe-rich nanodomains of Co2FeO4 become trapping sites for hydroxyl groups, contributing to a higher OER activity compared to that of CoFe2O4. However, the activity of Co2FeO4 drops considerably due to concurrent irreversible transformation towards CoIVO2 and pronounced Fe dissolution. In contrast, there is negligible elemental redistribution for CoFe2O4 after OER, except for surface structural transformation towards (FeIII, CoIII)2O3. Overall, our study provides a unique 3D compositional distribution of mixed Co-Fe spinel oxides, which gives atomic-scale insights into active sites and the deactivation of electrocatalysts during OER.

Nickel nitride–black phosphorus heterostructure nanosheets for boosting the electrocatalytic activity towards the oxygen evolution reaction

2019 ◽  
Vol 7 (38) ◽  
pp. 22063-22069 ◽  
Author(s):  
Tong Wu ◽  
Shaoning Zhang ◽  
Kejun Bu ◽  
Wei Zhao ◽  
Qingyuan Bi ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Transfer Rate ◽  
Active Sites ◽  
Hydroxyl Groups ◽  
High Electron ◽  
Electron Transfer Rate ◽  
Alkaline Fuel Cells ◽  
Nickel Nitride

The extraordinary oxygen evolution reaction (OER) in alkaline fuel cells and water-splitting systems demands a high electron transfer rate and catalysts with numerous active sites and massive hydroxyl groups.

scholarly journals The Effect of Iron Impurities on Transition Metal Catalysts for the Oxygen Evolution Reaction in Alkaline Environment: Activity Mediators or Active Sites?

2020 ◽  
Author(s):  
Ioannis Spanos ◽  
Justus Masa ◽  
Aleksandar Zeradjanin ◽  
Robert Schlögl
Keyword(s):  
Transition Metal ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Active Sites ◽  
Water Electrolysis ◽  
Metal Catalysts ◽  
Transition Metal Catalysts ◽  
Alkaline Water Electrolysis ◽  
Co Catalysts ◽  
Model Transition

AbstractThere is an ongoing debate on elucidating the actual role of Fe impurities in alkaline water electrolysis, acting either as reactivity mediators or as co-catalysts through synergistic interaction with the main catalyst material. This perspective summarizes the most prominent oxygen evolution reaction (OER) mechanisms mostly for Ni-based oxides as model transition metal catalysts and highlights the effect of Fe incorporation on the catalyst surface in the form of impurities originating from the electrolyte or co-precipitated in the catalyst lattice, in modulating the OER reaction kinetics, mechanism and stability. Graphic Abstract

Oriental and robust anchoring of Fe via anodic interfacial coordination assembly on ultrathin Co hydroxides for efficient water oxidation

Nanoscale ◽  
2021 ◽  
Author(s):  
Ya-Nan Zhou ◽  
Ruo-Yao Fan ◽  
Yu-Ning Cao ◽  
Hui-Ying Wang ◽  
Bin Dong ◽  
...  
Keyword(s):  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Water Oxidation ◽  
Active Sites

The oriental distribution and strong conjunction of Fe active sites in multiple metals hydroxides are very crucial to modulate the activity and stability for efficient oxygen evolution reaction (OER). Whereas,...

Cathodic Corrosion Activated Fe-based Nanoglass as Highly-Active and -Stable Oxygen Evolution Catalyst for Water Splitting

2021 ◽  
Author(s):  
Kaiyao Wu ◽  
Fei Chu ◽  
Yuying Meng ◽  
Kaveh Edalati ◽  
Qingsheng Gao ◽  
...  
Keyword(s):  
Water Splitting ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Amorphous Alloys ◽  
Precious Metal ◽  
Active Sites ◽  
Metal Free ◽  
Highly Active ◽  
Stable Oxygen ◽  
Surface Active

Transition metal-based amorphous alloys have attracted increasing attention as precious-metal-free electrocatalysts for oxygen evolution reaction (OER) of water splitting due to their high macro-conductivity and abundant surface active sites. However,...

A Co3O4/MnCO3 heterojunction on three-dimensional nickel foam for an enhanced oxygen evolution reaction

CrystEngComm ◽  
2020 ◽  
Vol 22 (23) ◽  
pp. 3984-3990 ◽  
Author(s):  
Guijin Yang ◽  
Botao Zhu ◽  
Daqiang Gao ◽  
Yujun Fu ◽  
Jing Zhao ◽  
...  
Keyword(s):  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Nickel Foam ◽  
Three Dimensional

A Co3O4/MnCO3 heterojunction on NF with a unique architecture exhibits prominent OER activity and stability that is superior to most Co3O4-based catalysts.

scholarly journals Intrinsic activity modulation and structural design of NiFe alloy catalysts for an efficient oxygen evolution reaction

2021 ◽  
Author(s):  
Qiaoling Kang ◽  
Dawei Lai ◽  
Wenyin Tang ◽  
Qingyi Lu ◽  
Feng Gao
Keyword(s):  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Structural Design ◽  
Active Sites ◽  
Intrinsic Activity ◽  
Effective Strategies ◽  
Alloy Catalysts

Effective strategies to increase the intrinsic activity by electronic modulation and to increase the number of active sites by structural design are discussed for improving the oxygen evolution activities of NiFe alloys.

scholarly journals Spin-sate reconfiguration induced by alternating magnetic field for efficient oxygen evolution reaction

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Gang Zhou ◽  
Peifang Wang ◽  
Hao Li ◽  
Bin Hu ◽  
Yan Sun ◽  
...  
Keyword(s):  
Reaction Kinetics ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Active Sites ◽  
Reaction Pathway ◽  
Low Cost ◽  
Orbital Interaction ◽  
New Paradigm ◽  
Metal Organic ◽  
Energy Conversion Devices

AbstractOxygen evolution reaction (OER) plays a determining role in electrochemical energy conversion devices, but challenges remain due to the lack of effective low-cost electrocatalysts and insufficient understanding about sluggish reaction kinetics. Distinguish from complex nano-structuring, this work focuses on the spin-related charge transfer and orbital interaction between catalysts and intermediates to accelerate catalytic reaction kinetics. Herein, we propose a simple magnetic-stimulation approach to rearrange spin electron occupation in noble-metal-free metal-organic frameworks (MOFs) with a feature of thermal-differentiated superlattice, in which the localized magnetic heating in periodic spatial distribution makes the spin flip occur at particular active sites, demonstrating a spin-dependent reaction pathway. As a result, the spin-rearranged Co0.8Mn0.2 MOF displays mass activities of 3514.7 A gmetal−1 with an overpotential of ~0.27 V, which is 21.1 times that of pristine MOF. Our findings provide a new paradigm for designing spin electrocatalysis and steering reaction kinetics.

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