scholarly journals Atom-by-atom electrodeposition of single isolated cobalt oxide molecules and clusters for studying the oxygen evolution reaction

2020 ◽  
Vol 117 (23) ◽  
pp. 12651-12656 ◽  
Author(s):  
Zhaoyu Jin ◽  
Allen J. Bard
Keyword(s):  
Cobalt Oxide ◽  
Oxygen Evolution ◽  
Single Molecule ◽  
Oxygen Evolution Reaction ◽  
Relative Rate ◽  
Alkaline Media ◽  
Limiting Current ◽  
Equivalent Radius ◽  
Molecular Catalyst ◽  
Oxygen Evolving

We report an electrodeposition protocol for preparing isolated cobalt oxide single molecules (Co1Ox) and clusters (ConOy) on a carbon fiber nanoelectrode. The as-prepared deposits are able to produce well-defined steady-state voltammograms for the oxygen evolution reaction (OER) in alkaline media, where the equivalent radius (rd) is estimated by the limiting current of hydroxide oxidation in accordance with the electrocatalytic amplification model. The size of isolated clusters obtained from the femtomolar Co2+solution through an atom-by-atom technique can reach as small as 0.21 nm (rd) which is approximately the length of Co–O bond in cobalt oxide. Therefore, the deposit was close to that of a Co1Oxsingle molecule with only one cobalt ion, the minimum unit of the cobalt-based oxygen-evolving catalyst. Additionally, the size-dependent catalysis of the OER on ConOydeposits shows a faster relative rate on the smaller cluster in terms of the potential at a given current density, implying the single molecular catalyst shows a superior OER activity.

scholarly journals The Influence of Fe Substitution in Lanthanum Calcium Cobalt Oxide on the Oxygen Evolution Reaction in Alkaline Media

2016 ◽  
Vol 163 (9) ◽  
pp. F1124-F1132 ◽  
Author(s):  
Maria A. Abreu-Sepulveda ◽  
Chetan Dhital ◽  
Ashfia Huq ◽  
Ling Li ◽  
Craig A. Bridges ◽  
...  
Keyword(s):  
Cobalt Oxide ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Alkaline Media ◽  
Calcium Cobalt Oxide ◽  
Fe Substitution

Chemically Coupled Cobalt Oxide Nanosheets Decorated onto the Surface of Multiwall Carbon Nanotubes for Favorable Oxygen Evolution Reaction

2021 ◽  
Vol 21 (4) ◽  
pp. 2660-2667
Author(s):  
Abdul Qayoom Mugheri ◽  
Aneela Tahira ◽  
Umair Aftab ◽  
Adeel Liaquat Bhatti ◽  
Ramesh Lal ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Composite Material ◽  
Cobalt Oxide ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Electrochemical Impedance ◽  
Multiwall Carbon Nanotubes ◽  
Alkaline Media ◽  
Transfer Resistance ◽  
Multiwall Carbon

Cobalt oxide has been widely investigated among potential transition metal oxides for the electrochemical energy conversion, storage, and water splitting. However, they have inherently low electronic conductivity and high corrosive nature in alkaline media. Herein, we propose a promising and facile approach to improve the conductivity and charge transport of cobalt oxide Co3O4 through chemical coupling with well-dispersed multiwall carbon nanotubes (MWCNTs) during hydrothermal treatment. The morphology of prepared composite material consisting of nanosheets which are anchored on the MWCNTs as confirmed by scanning electron microscopy (SEM). A cubic crystalline system is exhibited by the cobalt oxide as confirmed by the X-ray diffraction study. The Co, O, and C are the only elements present in the composite material. FTIR study has indicated the successful coupling of cobalt oxide with MWCNTs. The chemically coupled cobalt oxide onto the surface of MWCNTs composite is found highly active towards oxygen evolution reaction (OER) with a low onset potential 1.44 V versus RHE, low overpotential 262 mV at 10 mAcm-2 and small Tafel slope 81 mV dec-1. For continuous operation of 40 hours during durability test, no decay in activity was recorded. Electrochemical impedance study further revealed a low charge transfer resistance of 70.64 Ohms for the composite material during the electrochemical reaction and which strongly favored OER kinetics. This work provides a simple, low cost, and smartly designing electrocatalysts via hydrothermal reaction for the catalysis and energy storage applications.

Microwave-assisted synthesis of a nanoamorphous (Ni0.8,Fe0.2) oxide oxygen-evolving electrocatalyst containing only “fast” sites

2017 ◽  
Vol 5 (23) ◽  
pp. 11661-11670 ◽  
Author(s):  
Joseph M. Barforoush ◽  
Dylan T. Jantz ◽  
Tess E. Seuferling ◽  
Kelly R. Song ◽  
Laura C. Cummings ◽  
...  
Keyword(s):  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Precious Metal ◽  
High Efficiency ◽  
Alkaline Media ◽  
Microwave Assisted Synthesis ◽  
Iron Oxyhydroxides ◽  
Nickel Iron ◽  
Microwave Assisted ◽  
Oxygen Evolving

Nickel–iron oxyhydroxides (Ni1−xFexOOH) are non-precious metal electrocatalysts for the oxygen evolution reaction (OER) that have high efficiency in alkaline media.

scholarly journals Effects of Annealing Temperature on the Oxygen Evolution Reaction Activity of Copper–Cobalt Oxide Nanosheets

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 657
Author(s):  
Geul Han Kim ◽  
Yoo Sei Park ◽  
Juchan Yang ◽  
Myeong Je Jang ◽  
Jaehoon Jeong ◽  
...  
Keyword(s):  
High Activity ◽  
Cobalt Oxide ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
Cobalt Hydroxide ◽  
Ni Foam ◽  
Electron Conduction

Developing high performance, highly stable, and low-cost electrodes for the oxygen evolution reaction (OER) is challenging in water electrolysis technology. However, Ir- and Ru-based OER catalysts with high OER efficiency are difficult to commercialize as precious metal-based catalysts. Therefore, the study of OER catalysts, which are replaced by non-precious metals and have high activity and stability, are necessary. In this study, a copper–cobalt oxide nanosheet (CCO) electrode was synthesized by the electrodeposition of copper–cobalt hydroxide (CCOH) on Ni foam followed by annealing. The CCOH was annealed at various temperatures, and the structure changed to that of CCO at temperatures above 250 °C. In addition, it was observed that the nanosheets agglomerated when annealed at 300 °C. The CCO electrode annealed at 250 °C had a high surface area and efficient electron conduction pathways as a result of the direct growth on the Ni foam. Thus, the prepared CCO electrode exhibited enhanced OER activity (1.6 V at 261 mA/cm2) compared to those of CCOH (1.6 V at 144 mA/cm2), Co3O4 (1.6 V at 39 mA/cm2), and commercial IrO2 (1.6 V at 14 mA/cm2) electrodes. The optimized catalyst also showed high activity and stability under high pH conditions, demonstrating its potential as a low cost, highly efficient OER electrode material.

Thermally Prepared Mn2O3/RuO2/Ru Thin Films as Highly Active Catalysts for the Oxygen Evolution Reaction in Alkaline Media

2016 ◽  
Vol 3 (11) ◽  
pp. 1847-1855 ◽  
Author(s):  
Michelle P. Browne ◽  
Hugo Nolan ◽  
Brendan Twamley ◽  
Georg S. Duesberg ◽  
Paula E. Colavita ◽  
...  
Keyword(s):  
Thin Films ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Alkaline Media ◽  
Highly Active

Carbazole modification of Ruthenium Bipyridine–dicarboxylate Oxygen Evolution Molecular Catalyst

2021 ◽  
Author(s):  
Hiroki Otsuka ◽  
Atsushi Kobayashi ◽  
Masaki Yoshida ◽  
Masako Kato
Keyword(s):  
Oxygen Evolution ◽  
Pyridyl Ligands ◽  
Molecular Catalyst ◽  
Oxygen Evolving

We newly synthesised oxygen-evolving molecular Ru(II) catalysts with one or two carbazole moieties on the axial pyridyl ligands, namely [Ru(bda)(cbz-py)(py)] and [Ru(bda)(cbz-py)2] [C1 and C2; bdaH2 = 2, 2’-bipyridyl-6, 6’-dicarboxylic...

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