Amorphous Cobalt Phyllosilicate with Layered Crystalline Motifs as Water Oxidation Catalyst

The development of a high‐performance oxygen evolution reaction (OER) catalyst is pivotal for the practical realization of a water‐splitting system. Although an extensive search for OER catalysts has been performed in the past decades, cost‐effective catalysts remain elusive. Herein, an amorphous co...

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Bibliographic Details
Published in:Advanced materials (Weinheim) 2017-06, Vol.29 (21), p.n/a
Main Authors: Kim, Ju Seong, Park, Inchul, Jeong, Eun‐Suk, Jin, Kyoungsuk, Seong, Won Mo, Yoon, Gabin, Kim, Hyunah, Kim, Byunghoon, Nam, Ki Tae, Kang, Kisuk
Format: Article
Language:English
Subjects:
Absorption spectroscopy
Amorphous structure
Catalysis
Catalysts
Catalytic activity
Cobalt
Crystal structure
Current density
Density functional theory
electrocatalyst
layered (oxy)hydroxides
Mathematical analysis
Oxidation
oxygen evolution reaction
phyllosilicate
Water splitting
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Summary:The development of a high‐performance oxygen evolution reaction (OER) catalyst is pivotal for the practical realization of a water‐splitting system. Although an extensive search for OER catalysts has been performed in the past decades, cost‐effective catalysts remain elusive. Herein, an amorphous cobalt phyllosilicate (ACP) with layered crystalline motif prepared by a room‐temperature precipitation is introduced as a new OER catalyst; this material exhibits a remarkably low overpotential (η ≈ 367 mV for a current density of 10 mA cm−2). A structural investigation using X‐ray absorption spectroscopy reveals that the amorphous structure contains layered motifs similar to the structure of CoOOH, which is demonstrated to be responsible for the OER catalysis based on density functional theory calculations. However, the calculations also reveal that the local environment of the active site in the layered crystalline motif in the ACP is significantly modulated by the silicate, leading to a substantial reduction of η of the OER compared with that of CoOOH. This work proposes amorphous phyllosilicates as a new group of efficient OER catalysts and suggests that tuning of the catalytic activity by introducing redox‐inert groups may be a new unexplored avenue for the design of novel high‐performance catalysts. The amorphous cobalt phyllosilicate introduced in this study exhibits the basic nature of a phyllosilicate as well as superior oxygen evolution reaction (OER) catalytic activity. Density functional theory calculations on the OER mechanism suggest that the silicate component aids in substantially reducing the η of the catalytic active sites by modulating the local structure.
ISSN:0935-9648
1521-4095
DOI:10.1002/adma.201606893