Valence- and element-dependent water oxidation behaviors: in situ X-ray diffraction, absorption and electrochemical impedance spectroscopies

2017 ◽  
Vol 19 (13) ◽  
pp. 8681-8693 ◽  
Author(s):  
Chia-Shuo Hsu ◽  
Nian-Tzu Suen ◽  
Ying-Ya Hsu ◽  
Hsuan-Yu Lin ◽  
Ching-Wei Tung ◽  
...  
Keyword(s):  
Metal Oxides ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Water Oxidation ◽  
Electrochemical Impedance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Oxidation Behaviors

Various metal oxides of the spinel family have shown great potential towards the oxygen evolution reaction, but this behavior only works in specific cases.

Revealing the structural transformation of rutile RuO2via in situ X-ray absorption spectroscopy during the oxygen evolution reaction

2019 ◽  
Vol 48 (21) ◽  
pp. 7122-7129 ◽  
Author(s):  
Chia-Jui Chang ◽  
You-Chiuan Chu ◽  
Hao-Yu Yan ◽  
Yen-Fa Liao ◽  
Hao Ming Chen
Keyword(s):  
Oxygen Evolution ◽  
Structural Transformation ◽  
Absorption Spectroscopy ◽  
Oxygen Evolution Reaction ◽  
The State ◽  
X Ray ◽  
Alkaline Conditions ◽  
X Ray Absorption ◽  
State Of Art

The state-of-art RuO2 catalyst for the oxygen evolution reaction (OER) is measured by using in situ X-ray absorption spectroscopy (XAS) to elucidate the structural transformation during catalyzing the reaction in acidic and alkaline conditions.

Improving the performance of porous nickel foam for water oxidation using hydrothermally prepared Ni and Fe metal oxides

2017 ◽  
Vol 1 (1) ◽  
pp. 207-216 ◽  
Author(s):  
Michelle P. Browne ◽  
Joana M. Vasconcelos ◽  
João Coelho ◽  
Maria O'Brien ◽  
Aurelie A. Rovetta ◽  
...  
Keyword(s):  
Transition Metal ◽  
Metal Oxides ◽  
Oxygen Evolution ◽  
Transition Metal Oxides ◽  
Oxygen Evolution Reaction ◽  
Water Oxidation ◽  
Nickel Foam ◽  
Research Trends ◽  
Porous Nickel

Recent research trends have seen a rise in the interest in Transition Metal Oxides (TMO's) as catalysts for the Oxygen Evolution Reaction (OER).

scholarly journals Generation and Reactivity of a NiIII2(μ-1,2-peroxo) Complex

2020 ◽  
Author(s):  
Norman Zhao ◽  
Alexander S. Filatov ◽  
Jiaze Xie ◽  
Ethan A. Hill ◽  
John Anderson
Keyword(s):  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Oxidation States ◽  
Peroxo Complex ◽  
Intermediate Species ◽  
X Ray Diffraction ◽  
X Ray ◽  
Tetrabutylammonium Chloride ◽  
High Valent ◽  
X Ray Absorption

Ni-based oxide materials are promising candidates for catalyzing the oxygen evolution reaction. The detailed mechanism of water splitting in these systems has been of interest with a goal of understanding the intermediate species vital for catalytic activity. A potential intermediate species prior to release of oxygen is a bridging Ni<sup>III</sup><sub>2</sub>(<i>μ</i>-1,2-peroxo) complex. However, Ni<sub>2</sub>(<i>μ</i>-1,2-peroxo) complexes are rare in general and are unknown with oxidation states higher than Ni<sup>II</sup>. Herein, we report the isolation of such an unusual high-valent species in a Ni<sup>III</sup><sub>2</sub>(<i>μ</i>-1,2-peroxo) complex, which has been characterized using single-crystal X-ray diffraction and X-ray absorption, NMR, and UV-vis spectroscopies. In addition, treatment with excess tetrabutylammonium chloride results in regeneration of the precursor Ni–Cl species, implicating the reversible release of oxygen or a reactive oxygen species. Taken together, this suggests that Ni<sup>III</sup><sub>2</sub>(<i>μ</i>-1,2-peroxo) species are accessible and may be viable intermediates during the oxygen evolution reaction.

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.

Structural, electrochemical and mechanical studies of ultrasonic irradiation enhanced electroplating Ni coating

2018 ◽  
Vol 65 (4) ◽  
pp. 333-339 ◽  
Author(s):  
Chaolei Ban ◽  
Shuqin Zhu ◽  
Jie Ma ◽  
Fangreng Wang ◽  
Zhengfeng Jia ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Ultrasonic Irradiation ◽  
Design Methodology ◽  
Electrochemical Impedance ◽  
Steel Substrate ◽  
X Ray Diffraction ◽  
Content Type ◽  
X Ray ◽  
Mechanical Studies

Purpose Ni coating was electroplated on carbon steel substrate to protect carbon steel. Design/methodology/approach During electroplating, the ultrasonic irradiation (UI) (1 kHz) action was in situ used with different frequency. The influence of UI on the microstructure, mechanical and electrochemical performance of the coating was studied with scanning electron microscopy, X-ray diffraction, microhardness measurement, polarization curves and electrochemical impedance spectroscopy. Findings The results show that comparing that without UI imposition, UI during electroplating can refine the coating grain and decrease the micro-pores in the coating, resulting in improvement of the coating corrosion and hardness. Originality/value The imposition of UI action during electroplating Ni coating can remove intrinsic pores in the coating and compact the coating. The potential bimetallic cell between substrate and plating layer can be insulated to enhance the corrosion resistance of Ni coating. The imposition of UI action during electroplating Ni coating can refine Ni coating grain size and improve the coating haredness.

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.

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