Abstract

Iridium-based bimetallic alloy system with unique performance is of great interest for high-temperature corrosive environment as a barrier layer or for water splitting of hydrogen/oxygen evolution reactions as a highly efficient and stable electrocatalyst. In this work, iridium-cobalt (Ir–Co) thin films were galvanostatically electrodeposited on a copper (Cu) foam electrode as an electrocatalyst for water splitting in 1.0 M KOH alkaline medium. The effects of loading and solution temperature on hydrogen evolution performance of Ir–Co deposits were investigated. The results show that Ir–Co deposits were adhered to substrates, with porous structure and hollow topography. The concentrations of Ir in the deposits with the loadings of 4.6, 3.2 and 0.8 mg·cm−2 were 88, 88 and 75 wt%, respectively. Ir–Co deposit with the loading of 3.2 mg·cm−2 required an overpotential of 108 mV for hydrogen evolution reaction to reach a current density of 30 mA cm−2, having a low Tafel slope value of 36 mV·dec−1. The changes in the solution temperature and catalyst loading had a significant effect on hydrogen evolution performance of Ir–Co/Ir–Co–O electrocatalysts. With the increasing of catalyst loading, the electrocatalytic activity increased firstly and then decreased. As the solution temperature was increased from 20 to 40 °C, the electrocatalytic activity of Ir–Co–O electrocatalyst increased, and then decreased with the rising of temperature. The apparent thermal activation energy obtained from Arrhenius plot was ~13.9 kJ mol−1. Ir–Co/Ir–Co–O deposits exhibited relatively good electrocatalytic stability and durability. The present work demonstrates a possible pathway to develop a highly active and durable substitute for thin film electrocatalysts for water splitting of hydrogen evolution reaction.

Full Text
Paper version not known

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.