Fully Exposed Edge/Corner Active Sites in Fe Substituted-Ni(OH)2 Tube-in-Tube Arrays for Efficient Electrocatalytic Oxygen Evolution

2021 ◽  
pp. 120558
Author(s):  
Zi-Xiao Shi ◽  
Jia-Wei Zhao ◽  
Cheng-Fei Li ◽  
Han Xu ◽  
Gao-Ren Li
Keyword(s):  
Oxygen Evolution ◽  
Active Sites ◽  
Tube Arrays

Towards a Design of Active Oxygen Evolution Catalysts: Insights from Automated Density Functional Theory Calculations and Machine Learning

2019 ◽  
Author(s):  
Seoin Back ◽  
Kevin Tran ◽  
Zachary Ulissi
Keyword(s):  
Machine Learning ◽  
Oxygen Evolution ◽  
Active Sites ◽  
Density Functional ◽  
Chemical Space ◽  
Density Functional Theory Calculations ◽  
Catalyst Design ◽  
Transition Metal Catalysts ◽  
Oxide Materials ◽  
Design Strategies

<div> <div> <div> <div><p>Developing active and stable oxygen evolution catalysts is a key to enabling various future energy technologies and the state-of-the-art catalyst is Ir-containing oxide materials. Understanding oxygen chemistry on oxide materials is significantly more complicated than studying transition metal catalysts for two reasons: the most stable surface coverage under reaction conditions is extremely important but difficult to understand without many detailed calculations, and there are many possible active sites and configurations on O* or OH* covered surfaces. We have developed an automated and high-throughput approach to solve this problem and predict OER overpotentials for arbitrary oxide surfaces. We demonstrate this for a number of previously-unstudied IrO2 and IrO3 polymorphs and their facets. We discovered that low index surfaces of IrO2 other than rutile (110) are more active than the most stable rutile (110), and we identified promising active sites of IrO2 and IrO3 that outperform rutile (110) by 0.2 V in theoretical overpotential. Based on findings from DFT calculations, we pro- vide catalyst design strategies to improve catalytic activity of Ir based catalysts and demonstrate a machine learning model capable of predicting surface coverages and site activity. This work highlights the importance of investigating unexplored chemical space to design promising catalysts.<br></p></div></div></div></div><div><div><div> </div> </div> </div>

scholarly journals Spinel of Nickel-Cobalt Oxide with Rod-Like Architecture as Electrocatalyst for Oxygen Evolution Reaction

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 3918
Author(s):  
Anna Dymerska ◽  
Wojciech Kukułka ◽  
Marcin Biegun ◽  
Ewa Mijowska
Keyword(s):  
Cobalt Oxide ◽  
Oxygen Evolution ◽  
Active Sites ◽  
Solvothermal Reaction ◽  
Step Method ◽  
One Pot ◽  
Widespread Application ◽  
Nickel Cobalt ◽  
Slow Kinetics ◽  
Nickel Cobalt Oxide

The renewable energy technologies require electrocatalysts for reactions, such as the oxygen and/or hydrogen evolution reaction (OER/HER). They are complex electrochemical reactions that take place through the direct transfer of electrons. However, mostly they have high over-potentials and slow kinetics, that is why they require electrocatalysts to lower the over-potential of the reactions and enhance the reaction rate. The commercially used catalysts (e.g., ruthenium nanoparticles—Ru, iridium nanoparticles—Ir, and their oxides: RuO2, IrO2, platinum—Pt) contain metals that have poor stability, and are not economically worthwhile for widespread application. Here, we propose the spinel structure of nickel-cobalt oxide (NiCo2O4) fabricated to serve as electrocatalyst for OER. These structures were obtained by a facile two-step method: (1) One-pot solvothermal reaction and subsequently (2) pyrolysis or carbonization, respectively. This material exhibits novel rod-like morphology formed by tiny spheres. The presence of transition metal particles such as Co and Ni due to their conductivity and electron configurations provides a great number of active sites, which brings superior electrochemical performance in oxygen evolution and good stability in long-term tests. Therefore, it is believed that we propose interesting low-cost material that can act as a super stable catalyst in OER.

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,...

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.

scholarly journals Mononuclear Fe in N-doped carbon: computational elucidation of active sites for electrochemical oxygen reduction and oxygen evolution reactions

2020 ◽  
Vol 10 (4) ◽  
pp. 1006-1014 ◽  
Author(s):  
Rui Shang ◽  
Stephan N. Steinmann ◽  
Bo-Qing Xu ◽  
Philippe Sautet
Keyword(s):  
Oxygen Reduction ◽  
Oxygen Evolution ◽  
Electrostatic Potential ◽  
First Principles ◽  
Active Sites ◽  
High Potential ◽  
Major Influence ◽  
Co Doped ◽  
Electrochemical Oxygen

First principles simulations show that in Fe and N co-doped carbon, Fe coordination controls the activity for oxygen reduction and oxygen evolution reactions, and that including the electrostatic potential has a major influence at high potential.

scholarly journals Ultrathin Co–Fe hydroxide nanosheet arrays for improved oxygen evolution during water splitting

RSC Advances ◽  
2017 ◽  
Vol 7 (37) ◽  
pp. 22818-22824 ◽  
Author(s):  
Tingting Zhou ◽  
Zhen Cao ◽  
Heng Wang ◽  
Zhen Gao ◽  
Long Li ◽  
...  
Keyword(s):  
Surface Area ◽  
Water Splitting ◽  
Oxygen Evolution ◽  
Active Sites ◽  
Three Dimensional ◽  
Fe Doping ◽  
Nanosheet Arrays ◽  
Fe Hydroxide

The Fe-doping of hierarchical Co hydroxide nanosheet arrays (CoyFe1−y(OH)x NSAs) integrated on a three-dimensional electrode is shown to contribute to both increasing the available surface area and number of active sites.

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