Patterned Electrodeposition of Cobalt Selenide Nanostructure Arrays As a Highly Efficient Bifunctional Catalyst for Oxygen Reduction Reaction (ORR) and Oxygen Evolution Reaction (OER)

There is a growing interest in oxygen electrode catalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), as they play a key role in a wide range of renewable energy technologies such as fuel cells, metal-air batteries, and water splitting. Nevertheless, the development of highly-active bifunctional catalysts at low cost for both ORR and OER still remains a huge challenge [1]. Herein, we report, a cost effective alternative, viz. cobalt selenide Co­_x­Se­­_y nanotube and nanorod arrays which shows considerable catalytic activity afor OER and/or ORR., The Co_xSe_y nanostructure arrays were produced by a protocol developed recently in the Nath laboratory [2] which involves confined electrodeposition on lithographically created nanoelectrodes. ORR activity of catalysts were evaluated in acidic medium (Fig. 1). Coating the Co_xSe_y nanostructures with a thin layer of Pt (Co_xSe_y-Pt) also exhibits enhanced catalytic efficiency. ORR current densities of Co_xSe_y and Co_xSe_y-Pt are comparable with Pt which indicate the four electron reduction process of all catalysts. Besides ORR, Co_xSe_y exhibits excellent activity towards OER. The polarization curve (inset of Fig. 1) for Co_xSe_yin linear sweep voltammetry (LSV) conditions show higher current and earlier onset (ca. 330 mV) of catalytic current in comparison with Pt in 1M KOH solution. Detailed characterization and analysis of ORR/OER activity of catalyst will be presented along with structural and morphological characterization of the active catalyst surface and the relationship between morphology and the observed catalytic activity.

References:

1. N.I. Andersen, A. Serov, P. Atanassov Applied Catalysis B: Environmental, 2015, 163, 623.
2. S. Mishra and Manashi Nath, Nano Energy, 2013, 2, 1207