Fe2O3 hollow nanorods/CNT composites as an efficient electrocatalyst for oxygen evolution reaction

Abstract

Oxygen evolution reaction is a key half reaction in overall water splitting process and metal air batteries. However, this reaction is kinetically unfavorable and requires a large overpotential when conducted in the absence of a precious metal catalyst. Substituting these precious metal catalysts with more abundant transition metal oxide such as Fe2O3 is a key challenge for widespread applications of water splitting. The catalytic activity of the Fe2O3 for water oxidation is mostly limited by the poor electric conductivity and low electrolyte permeability on catalyst surface. To overcome these limitations in this work, we have synthesized a composite between Fe2O3 nanorods and oxidized multi-walled carbon nanotubes via a simple urea assisted co-precipitation method. The Fe2O3 nanorods with hollow interior and low crystallinity provided improved electrochemically active surface area and larger number of transportation channels for diffusion of electrolyte. While, introduction of the carbon nanotube caused significant drop in resistance associated with faradic process. Consequently, the Fe2O3/carbon nanotube composite displayed excellent catalytic activity which is superior to Fe2O3, carbon nanotubes and their physical mixture. It is noted that the present work provides a simple strategy for the development of high performance oxygen evolution catalyst based on Fe2O3.