Investigation on IrO2 supported on hydrogenated TiO2 nanotube array as OER electro-catalyst for water electrolysis

IrO2 was electro-deposited on hydrogenated TiO2 nanotube arrays (TNTA) to form IrO2/H-TNTA for oxygen evolution reaction (OER). Hydrogenation by calcining in H-2 atmosphere was conducted to improve the electric conductivity, which was owing to partially reduce of Ti4+ in TNTA. It was found that hydrogenated TiO2 can facilitate the electro-deposition of IrO2, and elevate the OER activity compared to that of non-calcined and air-calcined TNTA, which would be due to the improved conductivity of H-TNTA. IrO2/H-TNTA shows a fivefold higher activity than IrO2/air-TNTA with the same loading amount. The coverage of IrO2 on the surface of hydrogenated TNTA is crucial to the stability of catalyst and with the increased loading amount of IrO2, IrO2/H-TNTA shows much higher stability. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.