Co3O4 polyhedrons with enhanced electric conductivity as efficient water oxidation electrocatalysts in alkaline medium

• Published in: Journal of materials science 2018-03, Vol.53 (6), p.4323-4333
• Main Authors: Zhang, Shi-Yuan, Li, Ting-Ting, Zhu, Hong-Lin, Zheng, Yue-Qing
• Format: Article
• Language: English
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Classical Mechanics; Cobalt oxides; Crystallography and Scattering Methods; Electrical resistivity; Electrocatalysts; Electronic Materials; Materials Science; Oxidation; Oxygen evolution reactions; Polyhedra; Polymer Sciences; Solid Mechanics; Tafel slopes; Vacancies
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-017-1855-2

It is a great challenge to develop Co 3 O 4 -based electrocatalysts of excellent performance for oxygen evolution reaction, because of its poor electrical conductivity. In this paper, we have prepared pristine Co 3 O 4 (P-Co 3 O 4 ) and Co 3 O 4 -C polyhedrons via two different calcination strategies. Then we have also displayed a simple and green reduction method to synthesize reduced Co 3 O 4 (R-Co 3 O 4 ) polyhedron with abundant surface oxygen vacancies. Oxygen vacancies and the doping of carbon species can enhance conductivity of electrocatalysts, thus, improving their electrocatalytic activities obviously. R-Co 3 O 4 and Co 3 O 4 -C polyhedrons show lower overpotentials of 380 and 420 mV, respectively, compared to P-Co 3 O 4 polyhedron (520 mV) at the current density of 10 mA cm −2 in 1 M KOH solution (pH 13.7). And they also have smaller Tafel slopes of 86 and 78 mV dec −1 than that of P-Co 3 O 4 polyhedron (93 mV dec −1 ), respectively. The integrated strategy reported here provides the way to design high-performance electrocatalysts for water oxidation.