(422c) Teaching an Old Electrocatalyst to Do New Tricks

Electrocatalysis underlies several key clean energy technologies such as fuel cells and electrolyzers that are expected to be key components of a sustainable energy future. However, continued improvements in electrocatalyst activity, durability, and selectivity must be achieved in order to make this future a reality. In this study, we explore the use of electrocatalyst architectures based on metallic electrocatalysts that have been encapsulated by ultra-thin silicon oxide overlayers. These oxide layers are synthesized with a room temperature process and deposited as continuous layers onto metallic thin films and nanoparticles. The catalytic metal used in these studies is Platinum (Pt), an “old catalyst” material that is one of the most commonly used electrocatalysts for electrolyzers and fuel cells. Inspired by past studies on glass microelectrodes¹ and a recent study from our lab on oxide-coated nanoparticles,² we show that well-defined oxide overlayers deposited on smooth metal substrates can be highly permeable to certain electroactive species and thereby enable efficient and selective electrocatalysis at the metal oxide / metal interface. By systematically varying the thickness of the oxide overlayer, we explore its transport properties and influence on the performance of thin film hydrogen evolution electrocatalysts. Our studies show that the properties of an “old catalyst” like Pt can be greatly altered, and perhaps tuned, through the use of the ultra-thin metal oxide overlayers, which can be thought of as nanomembranes that can selectively control transport of reactants and products. These results highlight the potential of this membrane-coated electrocatalyst architecture to serve as a tunable, efficient, and stable platform for a variety of electrochemical reactions.

 References

1. J. Velmurugan, D. Zhan, and M. V. Mirkin, Nature Chemistry, 2, 498-502, 2010.

2. N. Y. Labrador, X. Li, Y. Liu, J. T. Koberstein, R. Wang, H. Tan, T. P. Moffat, and D. V. Esposito, Nano Letters, 16, 6452-6459, 2016.