Galvanic displacement as a route to highly active and durable extended surface electrocatalysts

Abstract

Spontaneous galvanic displacement has been utilized in the development of novel electrocatalysts. The process occurs when a less noble metal template contacts a more noble metal cation and combines aspects of corrosion and electrodeposition. The cost of platinum (Pt) limits the commercial deployment of proton exchange membrane fuel cells. Although carbon-supported Pt typically has a moderate mass activity for oxygen reduction, it is limited by a relatively modest specific activity (activity per unit surface area). Conversely, extended Pt surfaces typically have high specific activity for oxygen reduction but commonly have low surface areas. Catalysts formed by spontaneous galvanic displacement are ideally situated, being able to take advantage of the specific activities generally associated with the catalyst type while significantly improving upon the surface area. In addition to acidic oxygen reduction, spontaneous galvanic displacement has been used in the development of catalysts for a variety of electrochemical reactions: hydrogen oxidation, alcohol oxidation, and basic oxygen reduction. Materials for these reactions have been incorporated into this perspective. Spontaneous galvanic displacement is a promising route in catalyst synthesis and cases exist where these electrocatalysts have demonstrated state-of-the-art performance.