Polyaniline Coating Enables Electronic Structure Engineering in Fe3O4 to Promote Alkaline Oxygen Evolution Reaction

2021 ◽  
Author(s):  
Yang Zou ◽  
Yuan Huang ◽  
Liwen Jiang ◽  
Arindam Indra ◽  
Yongqing Wang ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Active Sites ◽  
Simple Process ◽  
Molecular Modification ◽  
Mild Conditions ◽  
Novel Strategy ◽  
Structure Engineering

Abstract The electronic structure of active sites is of importance for catalysts to achieve an optimized interaction with the intermediates. In this study, a unique organic-inorganic hybrid oxygen evolution reaction (OER) electrocatalyst composed of electrochemically inactive conducting polyaniline (PANI) and non-precious Fe-based oxide Fe3O4 is presented. PANI molecules were in-situ loaded on Fe3O4 nanoparticles through an efficient and simple process under mild conditions. The electronic structure of Fe3O4 was modulated by creating a strong interaction with PANI molecules, leading to enhanced activity and stability of the catalyst to achieve 10 mA cm-2 geometrical current density at overpotential of 265 mV in 1 M aqueous KOH solution. This work demonstrates that a highly efficient electrocatalyst can be achieved by molecular modification and provides a novel strategy for the optimization of the inactive non-precious catalysts.

A novel strategy to boost the oxygen evolution reaction activity of NiFe-LDHs with in situ synthesized 3D porous reduced graphene oxide matrix as both the substrate and electronic carrier

2019 ◽  
Vol 43 (17) ◽  
pp. 6555-6562 ◽  
Author(s):  
Yanfang Gu ◽  
Yuanqiang Wang ◽  
Wei An ◽  
Yong Men ◽  
Yichuan Rui ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Stable Operating ◽  
Reduced Graphene ◽  
Oxide Matrix ◽  
Novel Strategy ◽  
Operating Potential

NiFe-LDHs anchored on a 3D rGO matrix achieved a small overpotential and a relatively stable operating potential.

scholarly journals A Cobalt-Iron Double-Atom Catalyst for the Oxygen Evolution Reaction

2019 ◽  
Author(s):  
Lichen Bai ◽  
Chia-Shuo Hsu ◽  
Duncan Alexander ◽  
Hao Ming Chen ◽  
Xile Hu
Keyword(s):  
Oxygen Evolution ◽  
Active Site ◽  
Oxygen Evolution Reaction ◽  
Active Sites ◽  
Single Atom ◽  
X Ray ◽  
Highly Active ◽  
Cobalt Iron ◽  
X Ray Absorption

Single atom catalysts exhibit well-defined active sites and potentially maximum atomic efficiency. However, they are unsuitable for reactions that benefit from bimetallic promotion such as the oxygen evolution reaction (OER) in alkaline medium. Here we show that a single atom Co precatalyst can be in-situ transformed into a Co-Fe double atom catalyst for OER. This catalyst exhibits one of the highest turnover frequencies among metal oxides. Electrochemical, microscopic, and spectroscopic data including those from operando X-ray absorption spectroscopy, reveal a dimeric Co-Fe moiety as the active site of the catalyst. This work demonstrates double-atom catalysis as a promising approach for the developed of defined and highly active OER catalysts.

scholarly journals A Cobalt-Iron Double-Atom Catalyst for the Oxygen Evolution Reaction

2019 ◽  
Author(s):  
Lichen Bai ◽  
Chia-Shuo Hsu ◽  
Duncan Alexander ◽  
Hao Ming Chen ◽  
Xile Hu
Keyword(s):  
Oxygen Evolution ◽  
Active Site ◽  
Oxygen Evolution Reaction ◽  
Active Sites ◽  
Single Atom ◽  
X Ray ◽  
Highly Active ◽  
Cobalt Iron ◽  
X Ray Absorption

Single atom catalysts exhibit well-defined active sites and potentially maximum atomic efficiency. However, they are unsuitable for reactions that benefit from bimetallic promotion such as the oxygen evolution reaction (OER) in alkaline medium. Here we show that a single atom Co precatalyst can be in-situ transformed into a Co-Fe double atom catalyst for OER. This catalyst exhibits one of the highest turnover frequencies among metal oxides. Electrochemical, microscopic, and spectroscopic data including those from operando X-ray absorption spectroscopy, reveal a dimeric Co-Fe moiety as the active site of the catalyst. This work demonstrates double-atom catalysis as a promising approach for the developed of defined and highly active OER catalysts.

scholarly journals Surface reconstruction establishing Mott-Schottky heterojunction and built-in space-charging effect accelerating oxygen evolution reaction

Nano Research ◽  
2021 ◽  
Author(s):  
Yao Kang ◽  
Shuo Wang ◽  
Kwan San Hui ◽  
Shuxing Wu ◽  
Duc Anh Dinh ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Oxygen Evolution ◽  
Surface Reconstruction ◽  
Oxygen Evolution Reaction ◽  
Active Sites ◽  
Density Functional ◽  
Electrochemical Process ◽  
Ex Situ ◽  
Catalytic Activities ◽  
Spectroscopy Studies

AbstractStructural reconstruction of nanomaterials offers a fantastic way to regulate the electronic structure of active sites and promote their catalytic activities. However, how to properly facilitate surface reconstruction to overcome large overpotential that stimulate the surface reconstruction has remained elusive. Herein, we adopt a facile approach to activate surface reconstruction on Ni(OH)2 by incorporating F anions to achieve electro-derived structural oxidation process and further boost its oxygen evolution reaction (OER) activity. Ex situ Raman and X-ray photoemission spectroscopy studies indicate that F ions incorporation facilitated surface reconstruction and promotes the original Ni(OH)2 transformed into a mesoporous and amorphous F-NiOOH layer during the electrochemical process. Density functional theory (DFT) calculation reveals that this self-reconstructed NiOOH induces a space-charge effect on the p-n junction interface, which not only promotes the absorption of intermediates species (*OH, *O, and *OOH) and charge-transfer process during catalysis, but also leads to a strong interaction of the p-n junction interface to stabilize the materials. This work opens up a new possibility to regulate the electronic structure of active sites and promote their catalytic activities.

Unveiling the active sites of Ni–Fe phosphide/metaphosphate for efficient oxygen evolution under alkaline conditions

2019 ◽  
Vol 55 (53) ◽  
pp. 7687-7690 ◽  
Author(s):  
Can Huang ◽  
Ying Zou ◽  
Ya-Qian Ye ◽  
Ting Ouyang ◽  
Kang Xiao ◽  
...  
Keyword(s):  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Active Sites ◽  
Highly Active ◽  
Alkaline Conditions ◽  
Stable Oxygen

The highly active and stable oxygen evolution reaction (OER) performance of Ni–Fe phosphide/metaphosphate (Ni1−xFex-P/PO3) can originate from in situ generated Fe doped γ-NiOOH.

Interface modulation of a layer-by-layer electrodeposited FexCo(1−x)P/NiP@CC heterostructure for high-performance oxygen evolution reaction

2020 ◽  
Vol 4 (4) ◽  
pp. 1863-1874 ◽  
Author(s):  
Bezawit Z. Desalegn ◽  
Harsharaj S. Jadhav ◽  
Jeong Gil Seo
Keyword(s):  
Catalytic Activity ◽  
Transition Metal ◽  
Oxygen Evolution ◽  
Alkaline Medium ◽  
Oxygen Evolution Reaction ◽  
Active Sites ◽  
High Performance ◽  
Layer By Layer ◽  
Interface Modulation

Heterostructuring assisted trimetallic transition metal phoshide with in situ generated active sites, exhibits superior catalytic activity towards oxygen evolution reaction in alkaline medium.

A facile preparation of CoFe2O4 nanoparticles on polyaniline-functionalised carbon nanotubes as enhanced catalysts for the oxygen evolution reaction

2016 ◽  
Vol 4 (12) ◽  
pp. 4472-4478 ◽  
Author(s):  
Yang Liu ◽  
Jing Li ◽  
Feng Li ◽  
Wenzhu Li ◽  
Haidong Yang ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
High Performance ◽  
Cofe2o4 Nanoparticles ◽  
Multiwalled Carbon ◽  
Mild Conditions ◽  
Facile Preparation

A polyaniline-multiwalled carbon nanotube supported, high performance CoFe2O4 nanoparticle loaded electrocatalyst is synthesized through a novel and simple in situ process under mild conditions.

scholarly journals Quantum chemistry of the oxygen evolution reaction on cobalt(ii,iii) oxide – implications for designing the optimal catalyst

2016 ◽  
Vol 188 ◽  
pp. 199-226 ◽  
Author(s):  
Craig P. Plaisance ◽  
Karsten Reuter ◽  
Rutger A. van Santen
Keyword(s):  
Electronic Structure ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Active Sites ◽  
Density Functional ◽  
Oxidation Potential ◽  
Water Addition ◽  
Wide Range ◽  
A Site ◽  
Intrinsic Reactivity

Density functional theory is used to examine the changes in electronic structure that occur during the oxygen evolution reaction (OER) catalyzed by active sites on three different surface terminations of Co3O4. These three active sites have reactive oxo species with differing degrees of coordination by Co cations – a μ3-oxo on the (311) surface, a μ2-oxo on the (110)-A surface, and an η-oxo on the (110)-B surface. The kinetically relevant step on all surfaces over a wide range of applied potentials is the nucleophilic addition of water to the oxo, which is responsible for formation of the O–O bond. The intrinsic reactivity of a site for this step is found to increase as the coordination of the oxo decreases with the μ3-oxo on the (311) surface being the least reactive and the η-oxo on the (110)-B surface being the most reactive. A detailed analysis of the electronic changes occurring during water addition on the three sites reveals that this trend is due to both a decrease in the attractive local Madelung potential on the oxo and a decrease in electron withdrawal from the oxo by Co neighbors. Applying a similar electronic structure analysis to the oxidation steps preceding water addition in the catalytic cycle shows that analogous electronic changes occur during this process, explaining a correlation observed between the oxidation potential of a site and its intrinsic reactivity for water addition. This concept is then used to specify criteria for the design of an optimal OER catalyst at a given applied potential.

scholarly journals Perovskite With Tunable Active-Sites Oxidation State by High-Valence W for Enhanced Oxygen Evolution Reaction

2022 ◽  
Vol 9 ◽  
Author(s):  
Jiabiao Yan ◽  
Mingkun Xia ◽  
Chenguang Zhu ◽  
Dawei Chen ◽  
Fanglin Du
Keyword(s):  
Electronic Structure ◽  
Water Splitting ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Precious Metal ◽  
Active Sites ◽  
Perovskite Oxides ◽  
Intrinsic Activity ◽  
Excellent Activity ◽  
The Stability

Perovskite oxides have been established as a promising kind of catalyst for alkaline oxygen evolution reactions (OER), because of their regulated non-precious metal components. However, the surface lattice is amorphous during the reaction, which gradually decreases the intrinsic activity and stability of catalysts. Herein, the precisely control tungsten atoms substituted perovskite oxides (Pr0.5Ba0.5Co1-xWxO3-δ) nanowires were developed by electrostatic spinning. The activity and Tafel slope were both dependent on the W content in a volcano-like fashion, and the optimized Pr0.5Ba0.5Co0.8W0.2O3-δ exhibits both excellent activity and superior stability compared with other reported perovskite oxides. Due to the outermost vacant orbitals of W6+, the electronic structure of cobalt sites could be efficiently optimized. Meanwhile, the stronger W-O bond could also significantly improve the stability of latticed oxide atoms to impede the generation of surface amorphous layers, which shows good application value in alkaline water splitting.

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