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Metallic Single-Unit-Cell Orthorhombic Cobalt Diselenide Atomic Layers: Robust Water-Electrolysis Catalysts.
- Source :
-
Angewandte Chemie International Edition . Oct2015, Vol. 54 Issue 41, p12004-12008. 5p. - Publication Year :
- 2015
-
Abstract
- The bottleneck in water electrolysis lies in the kinetically sluggish oxygen evolution reaction (OER). Herein, conceptually new metallic non-metal atomic layers are proposed to overcome this drawback. Metallic single-unit-cell CoSe2 sheets with an orthorhombic phase are synthesized by thermally exfoliating a lamellar CoSe2-DETA hybrid. The metallic character of orthorhombic CoSe2 atomic layers, verified by DFT calculations and temperature-dependent resistivities, allows fast oxygen evolution kinetics with a lowered overpotential of 0.27 V. The single-unit-cell thickness means 66.7 % of the Co2+ ions are exposed on the surface and serve as the catalytically active sites. The lowered Co2+ coordination number down to 1.3 and 2.6, gives a lower Tafel slope of 64 mV dec−1 and higher turnover frequency of 745 h−1. Thus, the single-unit-cell CoSe2 sheets have around 2 and 4.5 times higher catalytic activity compared with the lamellar CoSe2-DETA hybrid and bulk CoSe2. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 14337851
- Volume :
- 54
- Issue :
- 41
- Database :
- Academic Search Index
- Journal :
- Angewandte Chemie International Edition
- Publication Type :
- Academic Journal
- Accession number :
- 110004207
- Full Text :
- https://doi.org/10.1002/anie.201505245