Indexed on: 03 Jul '18Published on: 03 Jul '18Published in: Chemistry - An Asian Journal
The relationship between controllable morphology and electrocatalytic activity of Co3O4 as well as CoSe2 for oxygen evolution reaction was explored in alkaline medium. Based on the time-dependent growth process of cobalt precursors, 1D Co3O4 nanorods and 2D Co3O4 nanosheets were successfully synthesized via a facile hydrothermal process at 180 oC by different reaction times, followed by calcination at 300 oC for 2h. Subsequently, 1D and 2D CoSe2 nanostructures were derived by seleniding Co3O4, which achieved the controllable synthesis of CoSe2 without templating agents. By comparing the electrocatalytic behavior of these Co-based catalysts in 1 M KOH electrolyte toward oxygen evolution reaction, it is found that both 2D Co3O4 and 2D CoSe2 nanocrystals have relative lower overpotential and better electrocatalysis stability than 1D nanostructures. 2D CoSe2 nanosheets require overpotentials of 372 mV to reach a current density of 50 mA cm-2 with a small Tafel slope of 74 mV decade-1. A systematic contrast of the electrocatalytic performance for OER increase in the order: 1D Co3O4 < 2D Co3O4 < 1D CoSe2 < 2D CoSe2. This work provides fundamental insights into the morphology-performance relationship of both Co3O4 and CoSe2 synthesized from the same approach, providing a solid guiding for designing OER catalysts. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.