Ultrathin YSZ Coating on Pt Cathode for High Thermal Stability and Enhanced Oxygen Reduction Reaction Activity

• Published in: Advanced energy materials Vol. 5; no. 10; pp. np - n/a
• Main Authors: Chang, Ikwhang, Ji, Sanghoon, Park, Joonho, Lee, Min Hwan, Cha, Suk Won
• Format: Journal Article
• Language: English
• Published: Weinheim Blackwell Publishing Ltd 01-05-2015; Wiley Subscription Services, Inc
• Subjects: Agglomeration; atomic layer deposition; Catalysis; cathode; Cathodes; Coating; Deposition; durability; Electrodes; Platinum; solid oxide fuel cell; Yttria stabilized zirconia
• ISSN: 1614-6832; 1614-6840
• DOI: 10.1002/aenm.201402251

A simple, yet effective approach of stabilizing the nanostructure of porous metal‐based electrodes and thus, extending the life of microsolid oxide fuel cells is demonstrated. In an effort to avoid thermal agglomeration of metal electrodes, an ultrathin yttria‐stabilized zirconia (YSZ) is coated on the porous metal (Pt) cathode by the atomic layer deposition, a scalable, and potentially high‐throughput deposition technique. A very thin YSZ coating is found to maintain the morphology of its underlying nanoporous Pt during high temperature operations (500 °C). More interestingly, the YSZ coating is also found to improve oxygen reduction reaction activity by ≈2.5 times. This improvement is attributed to an enhanced triple phase area, especially in the vicinity of the Pt–electrolyte interface; cross‐sectional electron microscopy images indicate that the initially uniform ultrathin YSZ layer becomes a partially agglomerated coating, a favorable structure for a maximized reaction area and fluent oxygen access to the Pt–electrolyte interface.
Porous metal‐based catalysts are prone to agglomeration during operation at elevated temperatures. An ultrathin oxide layer is presented that is coated on metal catalysts using an atomic layer deposition technique, which suppresses the agglomeration process significantly while enhancing electrocatalytic activities. The scheme is demonstrated for cathodes of micro solid oxide fuel cells operating at 500 °C, but it should be generically applicable to other electrochemical catalysis with metal‐based electrodes.