Structure and Valency of a Cobalt−Phosphate Water Oxidation Catalyst Determined by in Situ X-ray Spectroscopy

2010 ◽  
Vol 132 (39) ◽  
pp. 13692-13701 ◽  
Author(s):  
Matthew W. Kanan ◽  
Junko Yano ◽  
Yogesh Surendranath ◽  
Mircea Dincă ◽  
Vittal K. Yachandra ◽  
...  
Keyword(s):  
Water Oxidation ◽  
Oxidation Catalyst ◽  
X Ray ◽  
Cobalt Phosphate

The Key RuV=O Intermediate of Site-Isolated Mononuclear Water Oxidation Catalyst Detected by in Situ X-ray Absorption Spectroscopy

2017 ◽  
Vol 140 (1) ◽  
pp. 451-458 ◽  
Author(s):  
Dmitry Lebedev ◽  
Yuliana Pineda-Galvan ◽  
Yuki Tokimaru ◽  
Alexey Fedorov ◽  
Nicolas Kaeffer ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Water Oxidation ◽  
Oxidation Catalyst ◽  
X Ray ◽  
X Ray Absorption

Direct Observation of Active Nickel Oxide Cluster in Nickel–Borate Electrocatalyst for Water Oxidation by In Situ O K-Edge X-ray Absorption Spectroscopy

2015 ◽  
Vol 119 (33) ◽  
pp. 19279-19286 ◽  
Author(s):  
Masaaki Yoshida ◽  
Yosuke Mitsutomi ◽  
Takehiro Mineo ◽  
Masanari Nagasaka ◽  
Hayato Yuzawa ◽  
...  
Keyword(s):  
Nickel Oxide ◽  
Absorption Spectroscopy ◽  
Direct Observation ◽  
Water Oxidation ◽  
Oxide Cluster ◽  
X Ray ◽  
X Ray Absorption

scholarly journals In Situ EPR Characterization of a Cobalt Oxide Water Oxidation Catalyst at Neutral pH

Catalysts ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 926 ◽  
Author(s):  
Yury Kutin ◽  
Nicholas Cox ◽  
Wolfgang Lubitz ◽  
Alexander Schnegg ◽  
Olaf Rüdiger
Keyword(s):  
Cobalt Oxide ◽  
Water Oxidation ◽  
Large Scale ◽  
Low Cost ◽  
Operating Conditions ◽  
Oxidation Catalyst ◽  
O2 Evolution ◽  
Ligand Field ◽  
Neutral Ph

Here we report an in situ electron paramagnetic resonance (EPR) study of a low-cost, high-stability cobalt oxide electrodeposited material (Co-Pi) that oxidizes water at neutral pH and low over-potential, representing a promising system for future large-scale water splitting applications. Using CW X-band EPR we can follow the film formation from a Co(NO3)2 solution in phosphate buffer and quantify Co uptake into the catalytic film. As deposited, the film shows predominantly a Co(II) EPR signal, which converts into a Co(IV) signal as the electrode potential is increased. A purpose-built spectroelectrochemical cell allowed us to quantify the extent of Co(II) to Co(IV) conversion as a function of potential bias under operating conditions. Consistent with its role as an intermediate, Co(IV) is formed at potentials commensurate with electrocatalytic O2 evolution (+1.2 V, vs. SHE). The EPR resonance position of the Co(IV) species shifts to higher fields as the potential is increased above 1.2 V. Such a shift of the Co(IV) signal may be assigned to changes in the local Co structure, displaying a more distorted ligand field or more ligand radical character, suggesting it is this subset of sites that represents the catalytically ‘active’ component. The described spectroelectrochemical approach provides new information on catalyst function and reaction pathways of water oxidation.

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.

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