Enhancement of the Hydrogen Oxidation Reaction in Alkaline Media via a Bi-functional Effect Using Tantalum as an Oxophilic Agent on NiMo/C
Sang‐Hoon You, Hyejin Lee, Eunji Ahn, Kyu‐Su Kim, Byung‐Jo Lee, Dongwon Shin, Vinod K. Paidi, Donghwa Lee, Byungchan Bae, Kug‐Seung Lee, Yong‐Tae Kim
Abstract
To avoid the increase of cost owing to the use of Pt group metal (PGM) catalysts, anion-exchange membrane fuel cells (AEMFCs) operating in an alkaline electrolyte environment where non-precious metals can be used are promising. However, the performance limitations of PGM-free catalysts still need to be overcome. In this study, Ta-on-NiMo/C fabricated by adding Ta on the surface of commercial NiMo/C via physical vapor deposition was developed as an anodic catalyst for AEMFCs with advanced performance. The high oxophilicity of Ta ensures a continuous OH – supply, and the bifunctional effect between Ta and Ni accelerates the hydrogen oxidation reaction (HOR). Therefore, Ta-on-NiMo/C exhibited 1.5 times more HOR activity than bare NiMo/C in rotating disk electrode experiments. Furthermore, the effect of Ta as the oxophilic agent was demonstrated by verifying the enhanced performance in a membrane electrode assembly in which Ta-on-NiMo/C was applied as an anodic catalyst.