High-performance AEM unitized regenerative fuel cell using Pt-pyrochlore as bifunctional oxygen electrocatalyst

Significance Unitized regenerative fuel cells (URFCs) combine the functionalities of both electrolyzers and fuel cells in a single cell/stack, enabling lower weight, volume, and capital cost. A fixed-gas URFC (FG-URFC) has the advantage of efficient and easy gas management. A highly active and highly stable bifunctional oxygen electrocatalyst with low bifunctionality index (BI) helps in achieving high performance and high round-trip efficiencies (RTE) in a URFC. In this context, Pt-Pb 2 Ru 2 O 7-x electrocatalyst is synthesized and evaluated as bifunctional oxygen electrocatalyst in alkaline medium. This electrocatalyst exhibits a low BI with highly symmetric oxygen reduction and evolution activity. The FG-URFC using Pt-Pb 2 Ru 2 O 7-x shows high RTE for an anion exchange membrane FG-URFC, providing a pathway for the development of FG-URFCs for bidirectional energy and fuel production.